Configuration Reference for Kong Gateway

Kong will operate with default settings should all the values in your configuration be commented out. Upon starting, Kong looks for several default locations that might contain a configuration file:

/etc/kong/kong.conf
/etc/kong.conf

You can override this behavior by specifying a custom path for your configuration file using the -c / --conf argument in the CLI:

kong start --conf /path/to/kong.conf

The configuration format is straightforward: simply uncomment any property (comments are defined by the # character) and modify it to your needs. Boolean values can be specified as on/off or true/false for convenience.

Verifying your configuration

You can verify the integrity of your settings with the check command:

kong check {PATH/TO/kong.conf}
configuration at {PATH/TO/kong.conf} is valid

This command will take into account the environment variables you have currently set, and will error out in case your settings are invalid.

Additionally, you can also use the CLI in debug mode to have more insight as to what properties Kong is being started with:

kong start -c {kong.conf} --vv
2016/08/11 14:53:36 [verbose] no config file found at /etc/kong.conf
2016/08/11 14:53:36 [verbose] no config file found at /etc/kong/kong.conf
2016/08/11 14:53:36 [debug] admin_listen = "0.0.0.0:8001"
2016/08/11 14:53:36 [debug] database = "postgres"
2016/08/11 14:53:36 [debug] log_level = "notice"
[...]

When loading properties out of a configuration file, Kong will also look for environment variables of the same name. This allows you to fully configure Kong via environment variables, which is very convenient for container-based infrastructures, for example.

To override a setting using an environment variable, declare an environment variable with the name of the setting, prefixed with KONG_ and capitalized.

For example:

log_level = debug # in kong.conf

can be overridden with:

export KONG_LOG_LEVEL=error

Injecting Nginx directives

Tweaking the Nginx configuration of your Kong instances allows you to optimize its performance for your infrastructure.

When Kong starts, it builds an Nginx configuration file. You can inject custom Nginx directives to this file directly via your Kong configuration.

Any entry added to your kong.conf file that is prefixed by nginx_http_, nginx_proxy_ or nginx_admin_ will be converted into an equivalent Nginx directive by removing the prefix and added to the appropriate section of the Nginx configuration:

• Entries prefixed with nginx_http_ will be injected to the overall http block directive.

• Entries prefixed with nginx_proxy_ will be injected to the server block directive handling Kong’s proxy ports.

• Entries prefixed with nginx_admin_ will be injected to the server block directive handling Kong’s Admin API ports.

For example, if you add the following line to your kong.conf file:

nginx_proxy_large_client_header_buffers=16 128k

it will add the following directive to the proxy server block of Kong’s Nginx configuration:

Like any other entry in kong.conf, these directives can also be specified using environment variables as shown above. For example, if you declare an environment variable like this:

export KONG_NGINX_HTTP_OUTPUT_BUFFERS="4 64k"

This will result in the following Nginx directive being added to the http block:

output_buffers 4 64k;

As always, be mindful of your shell’s quoting rules specifying values containing spaces.

For more details on the Nginx configuration file structure and block directives, see .

For a list of Nginx directives, see https://nginx.org/en/docs/dirindex.html. Note however that some directives are dependent of specific Nginx modules, some of which may not be included with the official builds of Kong.

Including files via injected Nginx directives

For more complex configuration scenarios, such as adding entire new server blocks, you can use the method described above to inject an include directive to the Nginx configuration, pointing to a file containing your additional Nginx settings.

For example, if you create a file called my-server.kong.conf with the following contents:

# custom server
server {
  listen 2112;
  location / {
    # ...more settings...
    return 200;
  }
}

You can make the Kong node serve this port by adding the following entry to your kong.conf file:

nginx_http_include = /path/to/your/my-server.kong.conf

or, alternatively, by configuring it via an environment variable:

export KONG_NGINX_HTTP_INCLUDE="/path/to/your/my-server.kong.conf"

Now, when you start Kong, the server section from that file will be added to that file, meaning that the custom server defined in it will be responding, alongside the regular Kong ports:

curl -I http://127.0.0.1:2112
HTTP/1.1 200 OK
...

Note that if you use a relative path in an nginx_http_include property, that path will be interpreted relative to the value of the prefix property of your kong.conf file (or the value of the -p flag of kong start if you used it to override the prefix when starting Kong).

For the vast majority of use-cases, using the Nginx directive injection system explained above should be sufficient for customizing the behavior of Kong’s Nginx instance. This way, you can manage the configuration and tuning of your Kong node from a single kong.conf file (and optionally your own included files), without having to deal with custom Nginx configuration templates.

There are two scenarios in which you may want to make use of custom Nginx configuration templates directly:

• In the rare occasion that you may need to modify some of Kong’s default Nginx configuration that are not adjustable via its standard kong.conf properties, you can still modify the template used by Kong for producing its Nginx configuration and launch Kong using your customized template.

• If you need to embed Kong in an already running OpenResty instance, you can reuse Kong’s generated configuration and include it in your existing configuration.

Custom Nginx templates

Kong can be started, reloaded and restarted with an --nginx-conf argument, which must specify an Nginx configuration template. Such a template uses the templating engine, which is compiled using the given Kong configuration, before being dumped in your Kong prefix directory, moments before starting Nginx.

The default template for Kong Gateway can be found by entering the following command on the system running your Kong instance: find / -type d -name "templates" | grep kong. For open-source Kong Gateway, you can also see the .

The template is split in two Nginx configuration files: nginx.lua and nginx_kong.lua. The former is minimalistic and includes the latter, which contains everything Kong requires to run. When kong start runs, right before starting Nginx, it copies these two files into the prefix directory, which looks like so:

/usr/local/kong
├── nginx-kong.conf
└── nginx.conf

If you must tweak global settings that are defined by Kong but not adjustable via the Kong configuration in kong.conf, you can inline the contents of the nginx_kong.lua configuration template into a custom template file (in this example called custom_nginx.template) like this:

You can then start Kong with:

kong start -c kong.conf --nginx-conf custom_nginx.template

Embedding Kong in OpenResty

If you are running your own OpenResty servers, you can also easily embed Kong by including the Kong Nginx sub-configuration using the include directive. If you have an existing Nginx configuration, you can simply include the Kong-specific portion of the configuration which is output by Kong in a separate nginx-kong.conf file:

# my_nginx.conf
# ...your nginx settings...
http {
    include 'nginx-kong.conf';
    # ...your nginx settings...
}

You can then start your Nginx instance like so:

nginx -p /usr/local/openresty -c my_nginx.conf

and Kong will be running in that instance (as configured in nginx-kong.conf).

A common use case for API providers is to make Kong serve both a website and the APIs themselves over the Proxy port — 80 or 443 in production. For example, https://example.net (Website) and https://example.net/api/v1 (API).

To achieve this, we cannot simply declare a new virtual server block, like we did in the previous section. A good solution is to use a custom Nginx configuration template which inlines nginx_kong.lua and adds a new location block serving the website alongside the Kong Proxy location block:

# ---------------------
# custom_nginx.template
# ---------------------
worker_processes ${{NGINX_WORKER_PROCESSES}}; # can be set by kong.conf
daemon ${{NGINX_DAEMON}};                     # can be set by kong.conf
pid pids/nginx.pid;                      # this setting is mandatory
error_log logs/error.log ${{LOG_LEVEL}}; # can be set by kong.conf
events {}
http {
  # here, we inline the contents of nginx_kong.lua
  charset UTF-8;
  # any contents until Kong's Proxy server block
  ...
  # Kong's Proxy server block
  server {
    server_name kong;
    # any contents until the location / block
    # here, we declare our custom location serving our website
    # (or API portal) which we can optimize for serving static assets
    location / {
      root /var/www/example.net;
      index index.htm index.html;
      ...
    }
    # Kong's Proxy location / has been changed to /api/v1
    location /api/v1 {
      set $upstream_host nil;
      set $upstream_scheme nil;
      set $upstream_uri nil;
      # Any remaining configuration for the Proxy location
      ...
    }
  }
  # Kong's Admin server block goes below
  # ...
}

Properties reference

General section

prefix

Working directory. Equivalent to Nginx’s prefix path, containing temporary files and logs.

Each Kong process must have a separate working directory.

Default: /usr/local/kong/

log_level

Log level of the Nginx server. Logs are found at <prefix>/logs/error.log.

See for a list of accepted values.

Default: notice

proxy_access_log

Path for proxy port request access logs. Set this value to off to disable logging proxy requests.

If this value is a relative path, it will be placed under the prefix location.

Default: logs/access.log

proxy_error_log

Path for proxy port request error logs. The granularity of these logs is adjusted by the log_level property.

Default: logs/error.log

proxy_stream_access_log

Path for tcp streams proxy port access logs. Set this value to off to disable logging proxy requests.

If this value is a relative path, it will be placed under the prefix location.

basic is defined as '$remote_addr [$time_local] ' '$protocol $status $bytes_sent $bytes_received ' '$session_time'

Default: logs/access.log basic

proxy_stream_error_log

Path for tcp streams proxy port request error logs. The granularity of these logs is adjusted by the log_level property.

Default: logs/error.log

admin_access_log

Path for Admin API request access logs. If Hybrid Mode is enabled and the current node is set to be the Control Plane, then the connection requests from Data Planes are also written to this file with server name “kong_cluster_listener”.

Set this value to off to disable logging Admin API requests.

If this value is a relative path, it will be placed under the prefix location.

Default: logs/admin_access.log

admin_error_log

Path for Admin API request error logs. The granularity of these logs is adjusted by the log_level property.

Default: logs/error.log

status_access_log

Path for Status API request access logs. The default value of off implies that logging for this API is disabled by default.

If this value is a relative path, it will be placed under the prefix location.

Default: off

status_error_log

Path for Status API request error logs. The granularity of these logs is adjusted by the log_level property.

Default: logs/status_error.log

plugins

Comma-separated list of plugins this node should load. By default, only plugins bundled in official distributions are loaded via the bundled keyword.

Loading a plugin does not enable it by default, but only instructs Kong to load its source code, and allows to configure the plugin via the various related Admin API endpoints.

The specified name(s) will be substituted as such in the Lua namespace: kong.plugins.{name}.*.

When the off keyword is specified as the only value, no plugins will be loaded.

bundled and plugin names can be mixed together, as the following examples suggest:

• plugins = bundled,custom-auth,custom-log will include the bundled plugins plus two custom ones
• plugins = custom-auth,custom-log will only include the custom-auth and custom-log plugins.
• plugins = off will not include any plugins

Note: Kong will not start if some plugins were previously configured (i.e.

have rows in the database) and are not specified in this list. Before disabling a plugin, ensure all instances of it are removed before restarting Kong.

Note: Limiting the amount of available plugins can improve P99 latency when experiencing LRU churning in the database cache (i.e. when the configured mem_cache_size) is full.

Default: bundled

pluginserver_names

Comma-separated list of names for pluginserver processes. The actual names are used for log messages and to relate the actual settings.

Default: none

pluginserver_XXX_socket

Path to the unix socket used by the pluginserver.

Default: <prefix>/<XXX>.socket

pluginserver_XXX_start_cmd

Full command (including any needed arguments) to start the pluginserver

Default: /usr/local/bin/<XXX>

pluginserver_XXX_query_cmd

Full command to “query” the pluginserver. Should produce a JSON with the dump info of all plugins it manages

Default: /usr/local/bin/query_<XXX>

port_maps

With this configuration parameter, you can let the Kong to know about the port from which the packets are forwarded to it. This is fairly common when running Kong in a containerized or virtualized environment.

For example, port_maps=80:8000, 443:8443 instructs Kong that the port 80 is mapped to 8000 (and the port 443 to 8443), where 8000 and 8443 are the ports that Kong is listening to.

This parameter helps Kong set a proper forwarded upstream HTTP request header or to get the proper forwarded port with the Kong PDK (in case other means determining it has failed). It changes routing by a destination port to route by a port from which packets are forwarded to Kong, and similarly it changes the default plugin log serializer to use the port according to this mapping instead of reporting the port Kong is listening to.

Default: none

anonymous_reports

Send anonymous usage data such as error stack traces to help improve Kong.

Default: on

Hybrid Mode section

role

Use this setting to enable Hybrid Mode, This allows running some Kong nodes in a control plane role with a database and have them deliver configuration updates to other nodes running to DB-less running in a Data Plane role.

Valid values to this setting are:

• traditional: do not use Hybrid Mode.
• control_plane: this node runs in a control plane role. It can use a database and will deliver configuration updates to data plane nodes.
• data_plane: this is a data plane node. It runs DB-less and receives configuration updates from a control plane node.

Default: traditional

cluster_mtls

Sets the verification between nodes of the cluster.

Valid values to this setting are:

• shared: use a shared certificate/key pair specified with the cluster_cert and cluster_cert_key settings. Note that CP and DP nodes have to present the same certificate to establish mTLS connections.
• pki: use cluster_ca_cert, cluster_server_name and cluster_cert for verification. These are different certificates for each DP node, but issued by a cluster-wide common CA certificate: cluster_ca_cert.

Default: shared

cluster_cert

Filename of the cluster certificate to use when establishing secure communication between control and data plane nodes.

You can use the kong hybrid command to generate the certificate/key pair.

Under shared mode, it must be the same for all nodes. Under pki mode it should be a different certificate for each DP node.

Default: none

cluster_cert_key

Filename of the cluster certificate key to use when establishing secure communication between control and data plane nodes.

You can use the kong hybrid command to generate the certificate/key pair.

Under shared mode, it must be the same for all nodes. Under pki mode it should be a different certificate for each DP node.

Default: none

cluster_ca_cert

The trusted CA certificate file in PEM format used for Control Plane to verify Data Plane’s certificate and Data Plane to verify Control Plane’s certificate.

Required on data plane if cluster_mtls is set to pki.

If Control Plane certificate is issued by a well known CA, user can set lua_ssl_trusted_certificate=system on Data Plane and leave this field empty.

This field is ignored if cluster_mtls is set to shared.

Default: none

Hybrid Mode Data Plane section

cluster_server_name

The server name used in the SNI of the TLS connection from a DP node to a CP node.

Must match the Common Name (CN) or Subject Alternative Name (SAN) found in the CP certificate.

If cluster_mtls is set to shared, this setting is ignored and kong_clustering is used.

Default: none

cluster_control_plane

To be used by data plane nodes only: address of the control plane node from which configuration updates will be fetched, in host:port format.

Default: none

cluster_telemetry_endpoint

To be used by data plane nodes only: telemetry address of the control plane node to which telemetry updates will be posted in host:port format.

Default: none

Hybrid Mode Control Plane section

cluster_listen

Comma-separated list of addresses and ports on which the cluster control plane server should listen for data plane connections.

The cluster communication port of the control plane must be accessible by all the data planes within the same cluster. This port is mTLS protected to ensure end-to-end security and integrity.

This setting has no effect if role is not set to control_plane.

Connection made to this endpoint are logged to the same location as Admin API access logs.

See admin_access_log config description for more information.

Default: 0.0.0.0:8005

cluster_telemetry_listen

Comma-separated list of addresses and ports on which the cluster control plane server should listen for data plane telemetry connections.

The cluster communication port of the control plane must be accessible by all the data planes within the same cluster.

This setting has no effect if role is not set to control_plane.

Default: 0.0.0.0:8006

cluster_data_plane_purge_delay

How many seconds must pass from the time a DP node becomes offline to the time its entry gets removed from the database, as returned by the /clustering/data-planes Admin API endpoint.

This is to prevent the cluster data plane table from growing indefinitely. The default is set to 14 days. That is, if CP haven’t heard from a DP for 14 days, its entry will be removed.

Default: 1209600

cluster_ocsp

Whether to check for revocation status of DP certificates using OCSP (Online Certificate Status Protocol).

If enabled, the DP certificate should contain the “Certificate Authority Information Access” extension and the OCSP method with URI of which the OCSP responder can be reached from CP.

OCSP checks are only performed on CP nodes, it has no effect on DP nodes.

Valid values to this setting are:

• on: OCSP revocation check is enabled and DP must pass the check in order to establish connection with CP.
• off: OCSP revocation check is disabled.
• optional: OCSP revocation check will be attempted, however, if the required extension is not found inside DP provided certificate or communication with the OCSP responder failed, then DP is still allowed through.

Default: off

cluster_max_payload

This sets the maximum payload size allowed to be sent across from CP to DP in Hybrid mode.

Default is 4Mb - 4 * 1024 * 1024 due to historical reasons.

Default: 4194304

NGINX section

proxy_listen

Comma-separated list of addresses and ports on which the proxy server should listen for HTTP/HTTPS traffic.

The proxy server is the public entry point of Kong, which proxies traffic from your consumers to your backend services. This value accepts IPv4, IPv6, and hostnames.

Some suffixes can be specified for each pair:

• ssl will require that all connections made through a particular address/port be made with TLS enabled.
• http2 will allow for clients to open HTTP/2 connections to Kong’s proxy server.
• proxy_protocol will enable usage of the PROXY protocol for a given address/port.
• deferred instructs to use a deferred accept on Linux (the TCP_DEFER_ACCEPT socket option).
• bind instructs to make a separate bind() call for a given address:port pair.
• reuseport instructs to create an individual listening socket for each worker process allowing the Kernel to better distribute incoming connections between worker processes
• backlog=N sets the maximum length for the queue of pending TCP connections. This number should not be too small in order to prevent clients seeing “Connection refused” error connecting to a busy Kong instance. Note: on Linux, this value is limited by the setting of net.core.somaxconn Kernel parameter. In order for the larger backlog set here to take effect it is necessary to raise net.core.somaxconn at the same time to match or exceed the backlog number set.

This value can be set to off, thus disabling the HTTP/HTTPS proxy port for this node.

If stream_listen is also set to off, this enables ‘control-plane’ mode for this node (in which all traffic proxying capabilities are disabled). This node can then be used only to configure a cluster of Kong nodes connected to the same datastore.

Example: proxy_listen = 0.0.0.0:443 ssl, 0.0.0.0:444 http2 ssl

See for a description of the accepted formats for this and other *_listen values.

See https://www.nginx.com/resources/admin-guide/proxy-protocol/ for more details about the proxy_protocol parameter.

Not all *_listen values accept all formats specified in nginx’s documentation.

Default: 0.0.0.0:8000 reuseport backlog=16384, 0.0.0.0:8443 http2 ssl reuseport backlog=16384

proxy_url

Kong Proxy URL

The lookup, or balancer, address for your Kong Proxy nodes.

This value is commonly used in a microservices or service-mesh oriented architecture.

Accepted format (parts in parentheses are optional):

<scheme>://<IP / HOSTNAME>(:<PORT>(/<PATH>))

Examples:

• <scheme>://<IP>:<PORT> -> proxy_url = http://127.0.0.1:8000
• SSL <scheme>://<HOSTNAME> -> proxy_url = https://proxy.domain.tld
• <scheme>://<HOSTNAME>/<PATH> -> proxy_url = http://dev-machine/dev-285

By default, Kong Manager, and Dev Portal will use the window request host and append the resolved listener port depending on the requested protocol.

Default: none

stream_listen

Comma-separated list of addresses and ports on which the stream mode should listen.

This value accepts IPv4, IPv6, and hostnames.

Some suffixes can be specified for each pair:

• ssl will require that all connections made through a particular address/port be made with TLS enabled.
• proxy_protocol will enable usage of the PROXY protocol for a given address/port.
• bind instructs to make a separate bind() call for a given address:port pair.
• reuseport instructs to create an individual listening socket for each worker process allowing the Kernel to better distribute incoming connections between worker processes
• backlog=N sets the maximum length for the queue of pending TCP connections. This number should not be too small in order to prevent clients seeing “Connection refused” error connecting to a busy Kong instance. Note: on Linux, this value is limited by the setting of net.core.somaxconn Kernel parameter. In order for the larger backlog set here to take effect it is necessary to raise net.core.somaxconn at the same time to match or exceed the backlog number set.

Examples:

stream_listen = 127.0.0.1:7000 reuseport backlog=16384
stream_listen = 0.0.0.0:989 reuseport backlog=65536, 0.0.0.0:20
stream_listen = [::1]:1234 backlog=16384

By default this value is set to off, thus disabling the stream proxy port for this node.

See for a description of the formats that Kong might accept in stream_listen.

Default: off

admin_api_uri

Hierarchical part of a URI which is composed optionally of a host, port, and path at which the Admin API accepts HTTP or HTTPS traffic. When this config is disabled, Kong Manager will use the window protocol + host and append the resolved admin_listen HTTP/HTTPS port.

Default: none

admin_listen

Comma-separated list of addresses and ports on which the Admin interface should listen.

The Admin interface is the API allowing you to configure and manage Kong.

Access to this interface should be restricted to Kong administrators only. This value accepts IPv4, IPv6, and hostnames.

Some suffixes can be specified for each pair:

• ssl will require that all connections made through a particular address/port be made with TLS enabled.
• http2 will allow for clients to open HTTP/2 connections to Kong’s proxy server.
• proxy_protocol will enable usage of the PROXY protocol for a given address/port.
• deferred instructs to use a deferred accept on Linux (the TCP_DEFER_ACCEPT socket option).
• bind instructs to make a separate bind() call for a given address:port pair.
• reuseport instructs to create an individual listening socket for each worker process allowing the Kernel to better distribute incoming connections between worker processes
• backlog=N sets the maximum length for the queue of pending TCP connections. This number should not be too small in order to prevent clients seeing “Connection refused” error connecting to a busy Kong instance. Note: on Linux, this value is limited by the setting of net.core.somaxconn Kernel parameter. In order for the larger backlog set here to take effect it is necessary to raise net.core.somaxconn at the same time to match or exceed the backlog number set.

This value can be set to off, thus disabling the Admin interface for this node, enabling a ‘data-plane’ mode (without configuration capabilities) pulling its configuration changes from the database.

Example: admin_listen = 127.0.0.1:8444 http2 ssl

Default: 127.0.0.1:8001 reuseport backlog=16384, 127.0.0.1:8444 http2 ssl reuseport backlog=16384

status_listen

Comma-separated list of addresses and ports on which the Status API should listen.

The Status API is a read-only endpoint allowing monitoring tools to retrieve metrics, healthiness, and other non-sensitive information of the current Kong node.

The following suffix can be specified for each pair:

• ssl will require that all connections made through a particular address/port be made with TLS enabled.

This value can be set to off, disabling the Status API for this node.

Example: status_listen = 0.0.0.0:8100

Default: off

nginx_user

Defines user and group credentials used by worker processes. If group is omitted, a group whose name equals that of user is used.

Example: nginx_user = nginx www

Note: If the kong user and the kong group are not available, the default user and group credentials will be nobody nobody.

Default:

nginx_worker_processes

Determines the number of worker processes spawned by Nginx.

See for detailed usage of the equivalent Nginx directive and a description of accepted values.

Default: auto

nginx_daemon

Determines whether Nginx will run as a daemon or as a foreground process. Mainly useful for development or when running Kong inside a Docker environment.

See .

Default: on

mem_cache_size

Size of each of the two in-memory caches for database entities. The accepted units are k and m, with a minimum recommended value of a few MBs.

Note: As this option controls the size of two different cache entries, the total memory Kong uses to cache entities might be double this value.

Default: 128m

ssl_cipher_suite

Defines the TLS ciphers served by Nginx.

Accepted values are modern, intermediate, old, or custom.

See https://wiki.mozilla.org/Security/Server\_Side\_TLS for detailed descriptions of each cipher suite.

Default: intermediate

ssl_ciphers

Defines a custom list of TLS ciphers to be served by Nginx. This list must conform to the pattern defined by openssl ciphers.

This value is ignored if ssl_cipher_suite is not custom.

Default: none

ssl_protocols

Enables the specified protocols for client-side connections. The set of supported protocol versions also depends on the version of OpenSSL Kong was built with. This value is ignored if ssl_cipher_suite is not custom.

See

Default: TLSv1.1 TLSv1.2 TLSv1.3

ssl_prefer_server_ciphers

Specifies that server ciphers should be preferred over client ciphers when using the SSLv3 and TLS protocols. This value is ignored if ssl_cipher_suite is not custom.

See

Default: on

ssl_dhparam

Defines DH parameters for DHE ciphers from the predefined groups: ffdhe2048, ffdhe3072, ffdhe4096, ffdhe6144, ffdhe8192, or from the absolute path to a parameters file.

This value is ignored if ssl_cipher_suite is modern or intermediate. The reason is that modern has no ciphers that needs this, and intermediate uses ffdhe2048.

See

Default: none

ssl_session_tickets

Enables or disables session resumption through TLS session tickets. This has no impact when used with TLSv1.3.

Kong enables this by default for performance reasons, but it has security implications:

See http://nginx.org/en/docs/http/ngx\_http\_ssl\_module.html#ssl\_session\_tickets

Default: on

ssl_session_timeout

Specifies a time during which a client may reuse the session parameters. See the rationale: https://github.com/mozilla/server-side-tls/issues/198

See

Default: 1d

ssl_cert

Comma-separated list of the absolute path to the certificates for proxy_listen values with TLS enabled.

If more than one certificates are specified, it can be used to provide alternate type of certificate (for example, ECC certificate) that will be served to clients that supports them. Note to properly serve using ECC certificates, it is recommended to also set ssl_cipher_suite to modern or intermediate.

Unless this option is explicitly set, Kong will auto-generate a pair of default certificates (RSA + ECC) first time it starts up and use it for serving TLS requests.

Default: none

ssl_cert_key

Comma-separated list of the absolute path to the keys for proxy_listen values with TLS enabled.

If more than one certificate was specified for ssl_cert, then this option should contain the corresponding key for all certificates provided in the same order.

Unless this option is explicitly set, Kong will auto-generate a pair of default private keys (RSA + ECC) first time it starts up and use it for serving TLS requests.

Default: none

client_ssl

Determines if Nginx should attempt to send client-side TLS certificates and perform Mutual TLS Authentication with upstream service when proxying requests.

Default: off

client_ssl_cert

If client_ssl is enabled, the absolute path to the client certificate for the proxy_ssl_certificate directive.

This value can be overwritten dynamically with the client_certificate attribute of the Service object.

Default: none

client_ssl_cert_key

If client_ssl is enabled, the absolute path to the client TLS key for the proxy_ssl_certificate_key directive.

This value can be overwritten dynamically with the client_certificate attribute of the Service object.

Default: none

admin_ssl_cert

Comma-separated list of the absolute path to the certificates for admin_listen values with TLS enabled.

See docs for ssl_cert for detailed usage.

Default: none

admin_ssl_cert_key

Comma-separated list of the absolute path to the keys for admin_listen values with TLS enabled.

See docs for ssl_cert_key for detailed usage.

Default: none

status_ssl_cert

Comma-separated list of the absolute path to the certificates for status_listen values with TLS enabled.

See docs for ssl_cert for detailed usage.

Default: none

status_ssl_cert_key

Comma-separated list of the absolute path to the keys for status_listen values with TLS enabled.

See docs for ssl_cert_key for detailed usage.

Default: none

headers

Comma-separated list of headers Kong should inject in client responses.

Accepted values are:

• Server: Injects Server: kong/x.y.z on Kong-produced response (e.g. Admin API, rejected requests from auth plugin).
• Via: Injects Via: kong/x.y.z for successfully proxied requests.
• X-Kong-Proxy-Latency: Time taken (in milliseconds) by Kong to process a request and run all plugins before proxying the request upstream.
• X-Kong-Response-Latency: time taken (in millisecond) by Kong to produce a response in case of e.g. plugin short-circuiting the request, or in in case of an error.
• X-Kong-Upstream-Latency: Time taken (in milliseconds) by the upstream service to send response headers.
• X-Kong-Admin-Latency: Time taken (in milliseconds) by Kong to process an Admin API request.
• X-Kong-Upstream-Status: The HTTP status code returned by the upstream service. This is particularly useful for clients to distinguish upstream statuses if the response is rewritten by a plugin.
• server_tokens: Same as specifying both Server and Via.
• latency_tokens: Same as specifying X-Kong-Proxy-Latency, X-Kong-Response-Latency, X-Kong-Admin-Latency and X-Kong-Upstream-Latency

In addition to those, this value can be set to off, which prevents Kong from injecting any of the above headers. Note that this does not prevent plugins from injecting headers of their own.

Example: headers = via, latency_tokens

Default: server_tokens, latency_tokens

trusted_ips

Defines trusted IP addresses blocks that are known to send correct X-Forwarded-* headers.

Requests from trusted IPs make Kong forward their X-Forwarded-* headers upstream.

Non-trusted requests make Kong insert its own X-Forwarded-* headers.

This property also sets the set_real_ip_from directive(s) in the Nginx configuration. It accepts the same type of values (CIDR blocks) but as a comma-separated list.

To trust all /!\ IPs, set this value to 0.0.0.0/0,::/0.

If the special value unix: is specified, all UNIX-domain sockets will be trusted.

See for examples of accepted values.

Default: none

real_ip_header

Defines the request header field whose value will be used to replace the client address.

This value sets the ngx_http_realip_module directive of the same name in the Nginx configuration.

If this value receives proxy_protocol:

• at least one of the proxy_listen entries must have the proxy_protocol flag enabled.
• the proxy_protocol parameter will be appended to the listen directive of the Nginx template.

See for a description of this directive.

Default: X-Real-IP

real_ip_recursive

See for a description of this directive.

Default: off

error_default_type

Default MIME type to use when the request Accept header is missing and Nginx is returning an error for the request.

Accepted values are text/plain, text/html, application/json, and application/xml.

Default: text/plain

upstream_keepalive_pool_size

Sets the default size of the upstream keepalive connection pools.

Upstream keepalive connection pools are segmented by the dst ip/dst port/SNI attributes of a connection.

A value of 0 will disable upstream keepalive connections by default, forcing each upstream request to open a new connection.

Default: 60

upstream_keepalive_max_requests

Sets the default maximum number of requests than can be proxied upstream through one keepalive connection.

After the maximum number of requests is reached, the connection will be closed.

A value of 0 will disable this behavior, and a keepalive connection can be used to proxy an indefinite number of requests.

Default: 100

upstream_keepalive_idle_timeout

Sets the default timeout (in seconds) for which an upstream keepalive connection should be kept open. When the timeout is reached while the connection has not been reused, it will be closed.

A value of 0 will disable this behavior, and an idle keepalive connection may be kept open indefinitely.

Default: 60

Nginx directives can be dynamically injected in the runtime nginx.conf file without requiring a custom Nginx configuration template.

All configuration properties respecting the naming scheme nginx_<namespace>_<directive> will result in <directive> being injected in the Nginx configuration block corresponding to the property’s <namespace>.

Example: nginx_proxy_large_client_header_buffers = 8 24k

Will inject the following directive in Kong’s proxy server {} block:

large_client_header_buffers 8 24k;

The following namespaces are supported:

• nginx_main_<directive>: Injects <directive> in Kong’s configuration main context.
• nginx_events_<directive>: Injects <directive> in Kong’s events {} block.
• nginx_http_<directive>: Injects <directive> in Kong’s http {} block.
• nginx_proxy_<directive>: Injects <directive> in Kong’s proxy server {} block.
• nginx_upstream_<directive>: Injects <directive> in Kong’s proxy upstream {} block.
• nginx_admin_<directive>: Injects <directive> in Kong’s Admin API server {} block.
• nginx_status_<directive>: Injects <directive> in Kong’s Status API server {} block (only effective if status_listen is enabled).
• nginx_stream_<directive>: Injects <directive> in Kong’s stream module stream {} block (only effective if stream_listen is enabled).
• nginx_sproxy_<directive>: Injects <directive> in Kong’s stream module server {} block (only effective if stream_listen is enabled).
• nginx_supstream_<directive>: Injects <directive> in Kong’s stream module upstream {} block.

As with other configuration properties, Nginx directives can be injected via environment variables when capitalized and prefixed with KONG_.

Example: KONG_NGINX_HTTP_SSL_PROTOCOLS -> nginx_http_ssl_protocols

Will inject the following directive in Kong’s http {} block:

ssl_protocols <value>;

If different sets of protocols are desired between the proxy and Admin API server, you may specify nginx_proxy_ssl_protocols and/or nginx_admin_ssl_protocols, both of which taking precedence over the http {} block.

nginx_main_worker_rlimit_nofile

Changes the limit on the maximum number of open files for worker processes.

The special and default value of auto sets this value to ulimit -n with the upper bound limited to 16384 as a measure to protect against excess memory use.

See

Default: auto

nginx_events_worker_connections

Sets the maximum number of simultaneous connections that can be opened by a worker process.

The special and default value of auto sets this value to ulimit -n with the upper bound limited to 16384 as a measure to protect against excess memory use.

See

Default: auto

nginx_http_client_header_buffer_size

Sets buffer size for reading the client request headers.

See

Default: 1k

nginx_http_large_client_header_buffers

Sets the maximum number and size of buffers used for reading large clients requests headers.

See

Default: 4 8k

nginx_http_client_max_body_size

Defines the maximum request body size allowed by requests proxied by Kong, specified in the Content-Length request header. If a request exceeds this limit, Kong will respond with a 413 (Request Entity Too Large). Setting this value to 0 disables checking the request body size.

See

Default: 0

nginx_admin_client_max_body_size

Defines the maximum request body size for Admin API.

Default: 10m

nginx_http_client_body_buffer_size

Defines the buffer size for reading the request body. If the client request body is larger than this value, the body will be buffered to disk. Note that when the body is buffered to disk, Kong plugins that access or manipulate the request body may not work, so it is advisable to set this value as high as possible (e.g., set it as high as client_max_body_size to force request bodies to be kept in memory). Do note that high-concurrency environments will require significant memory allocations to process many concurrent large request bodies.

See http://nginx.org/en/docs/http/ngx\_http\_core\_module.html#client\_body\_buffer\_size

Default: 8k

nginx_admin_client_body_buffer_size

Defines the buffer size for reading the request body on Admin API.

Default: 10m

nginx_http_lua_regex_match_limit

Global MATCH_LIMIT for PCRE regex matching. The default of 100000 should ensure at worst any regex Kong executes could finish within roughly 2 seconds.

Default: 100000

Datastore section

Kong can run with a database to store coordinated data between Kong nodes in a cluster, or without a database, where each node stores its information independently in memory.

When using a database, Kong will store data for all its entities (such as Routes, Services, Consumers, and Plugins) in either Cassandra or PostgreSQL, and all Kong nodes belonging to the same cluster must connect themselves to the same database.

Kong supports the following database versions:

• PostgreSQL: 9.5 and above.
• Cassandra: 2.2 and above.

When not using a database, Kong is said to be in “DB-less mode”: it will keep its entities in memory, and each node needs to have this data entered via a declarative configuration file, which can be specified through the declarative_config property, or via the Admin API using the /config endpoint.

When using Postgres as the backend storage, you can optionally enable Kong to serve read queries from a separate database instance.

When the number of proxies is large, this can greatly reduce the load on the main Postgres instance and achieve better scalability. It may also reduce the latency jitter if the Kong proxy node’s latency to the main Postgres instance is high.

The read-only Postgres instance only serves read queries and write queries still goes to the main connection. The read-only Postgres instance can be eventually consistent while replicating changes from the main instance.

At least the pg_ro_host config is needed to enable this feature.

By default, all other database config for the read-only connection are inherited from the corresponding main connection config described above but may be optionally overwritten explicitly using the pg_ro_* config below.

database

Determines which of PostgreSQL or Cassandra this node will use as its datastore.

Accepted values are postgres, cassandra, and off.

Default: postgres

Postgres settings

Cassandra settings

declarative_config

The path to the declarative configuration file which holds the specification of all entities (Routes, Services, Consumers, etc.) to be used when the database is set to off.

Entities are stored in Kong’s in-memory cache, so you must ensure that enough memory is allocated to it via the mem_cache_size property. You must also ensure that items in the cache never expire, which means that db_cache_ttl should preserve its default value of 0.

If the Hybrid mode role is set to data_plane and there’s no configuration cache file, this configuration is used before connecting to the Control Plane node as a user-controlled fallback.

Default: none

declarative_config_string

The declarative configuration as a string

Default: none

Datastore Cache section

In order to avoid unnecessary communication with the datastore, Kong caches entities (such as APIs, Consumers, Credentials…) for a configurable period of time. It also handles invalidations if such an entity is updated.

This section allows for configuring the behavior of Kong regarding the caching of such configuration entities.

db_update_frequency

Frequency (in seconds) at which to check for updated entities with the datastore.

When a node creates, updates, or deletes an entity via the Admin API, other nodes need to wait for the next poll (configured by this value) to eventually purge the old cached entity and start using the new one.

Default: 5

db_update_propagation

Time (in seconds) taken for an entity in the datastore to be propagated to replica nodes of another datacenter.

When in a distributed environment such as a multi-datacenter Cassandra cluster, this value should be the maximum number of seconds taken by Cassandra to propagate a row to other datacenters.

When set, this property will increase the time taken by Kong to propagate the change of an entity.

Single-datacenter setups or PostgreSQL servers should suffer no such delays, and this value can be safely set to 0.

Default: 0

db_cache_ttl

Time-to-live (in seconds) of an entity from the datastore when cached by this node.

Database misses (no entity) are also cached according to this setting if you do not configure db_cache_neg_ttl.

If set to 0 (default), such cached entities or misses never expire.

Default: 0

db_cache_neg_ttl

Time-to-live (in seconds) of a datastore miss (no entity).

If not specified (default), db_cache_ttl value will be used instead.

If set to 0, misses will never expire.

Default: none

db_resurrect_ttl

Time (in seconds) for which stale entities from the datastore should be resurrected for when they cannot be refreshed (e.g., the datastore is unreachable). When this TTL expires, a new attempt to refresh the stale entities will be made.

Default: 30

db_cache_warmup_entities

Entities to be pre-loaded from the datastore into the in-memory cache at Kong start-up.

This speeds up the first access of endpoints that use the given entities.

When the services entity is configured for warmup, the DNS entries for values in its host attribute are pre-resolved asynchronously as well.

Cache size set in mem_cache_size should be set to a value large enough to hold all instances of the specified entities.

If the size is insufficient, Kong will log a warning.

Default: services

DNS Resolver section

By default, the DNS resolver will use the standard configuration files /etc/hosts and /etc/resolv.conf. The settings in the latter file will be overridden by the environment variables LOCALDOMAIN and RES_OPTIONS if they have been set.

Kong will resolve hostnames as either SRV or A records (in that order, and CNAME records will be dereferenced in the process).

In case a name was resolved as an SRV record it will also override any given port number by the port field contents received from the DNS server.

The DNS options SEARCH and NDOTS (from the /etc/resolv.conf file) will be used to expand short names to fully qualified ones. So it will first try the entire SEARCH list for the SRV type, if that fails it will try the SEARCH list for A, etc.

For the duration of the ttl, the internal DNS resolver will loadbalance each request it gets over the entries in the DNS record. For SRV records the weight fields will be honored, but it will only use the lowest field entries in the record.

dns_resolver

Comma separated list of nameservers, each entry in ip[:port] format to be used by Kong. If not specified the nameservers in the local resolv.conf file will be used.

Port defaults to 53 if omitted. Accepts both IPv4 and IPv6 addresses.

Default: none

dns_hostsfile

The hosts file to use. This file is read once and its content is static in memory.

To read the file again after modifying it, Kong must be reloaded.

Default: /etc/hosts

dns_order

The order in which to resolve different record types. The LAST type means the type of the last successful lookup (for the specified name). The format is a (case insensitive) comma separated list.

Default: LAST,SRV,A,CNAME

dns_valid_ttl

By default, DNS records are cached using the TTL value of a response. If this property receives a value (in seconds), it will override the TTL for all records.

Default: none

dns_stale_ttl

Defines, in seconds, how long a record will remain in cache past its TTL. This value will be used while the new DNS record is fetched in the background.

Stale data will be used from expiry of a record until either the refresh query completes, or the dns_stale_ttl number of seconds have passed.

Default: 4

dns_not_found_ttl

TTL in seconds for empty DNS responses and “(3) name error” responses.

Default: 30

dns_error_ttl

TTL in seconds for error responses.

Default: 1

dns_no_sync

If enabled, then upon a cache-miss every request will trigger its own dns query.

When disabled multiple requests for the same name/type will be synchronised to a single query.

Default: off

Tuning & Behavior section

worker_consistency

Defines whether this node should rebuild its state synchronously or asynchronously (the balancers and the router are rebuilt on updates that affects them, e.g., updates to Routes, Services or Upstreams, via the Admin API or loading a declarative configuration file).

Accepted values are:

• strict: the router will be rebuilt synchronously, causing incoming requests to be delayed until the rebuild is finished.
• eventual: the router will be rebuilt asynchronously via a recurring background job running every second inside of each worker.

Note that strict ensures that all workers of a given node will always proxy requests with an identical router, but that increased long tail latency can be observed if frequent Routes and Services updates are expected.

Using eventual will help preventing long tail latency issues in such cases, but may cause workers to route requests differently for a short period of time after Routes and Services updates.

Default: strict

worker_state_update_frequency

Defines how often the worker state changes are checked with a background job. When a change is detected, a new router or balancer will be built, as needed. Raising this value will decrease the load on database servers and result in less jitter in proxy latency, but it might take more time to propagate changes to each individual worker.

Default: 5

Miscellaneous section

Additional settings inherited from lua-nginx-module allowing for more flexibility and advanced usage.

See the lua-nginx-module documentation for more information:

lua_ssl_trusted_certificate

Comma-separated list of paths to certificate authority files for Lua cosockets in PEM format.

The special value system attempts to search for the “usual default” provided by each distro, according to an arbitrary heuristic. In the current implementation, The following pathnames will be tested in order, and the first one found will be used:

• /etc/ssl/certs/ca-certificates.crt (Debian/Ubuntu/Gentoo)
• /etc/pki/tls/certs/ca-bundle.crt (Fedora/RHEL 6)
• /etc/ssl/ca-bundle.pem (OpenSUSE)
• /etc/pki/tls/cacert.pem (OpenELEC)
• /etc/pki/ca-trust/extracted/pem/tls-ca-bundle.pem (CentOS/RHEL 7)
• /etc/ssl/cert.pem (OpenBSD, Alpine)

If no file is found on any of these paths, an error will be raised.

system can be used by itself or in conjunction with other CA filepaths.

When pg_ssl_verify or cassandra_ssl_verify are enabled, these certificate authority files will be used for verifying Kong’s database connections.

See

Default: none

lua_ssl_verify_depth

Sets the verification depth in the server certificates chain used by Lua cosockets, set by lua_ssl_trusted_certificate.

This includes the certificates configured for Kong’s database connections.

If the maximum depth is reached before reaching the end of the chain, verification will fail. This helps mitigate certificate based DoS attacks.

See

Default: 1

lua_ssl_protocols

Defines the TLS versions supported when handshaking with OpenResty’s TCP cosocket APIs.

This affects connections made by Lua code, such as connections to the database Kong uses, or when sending logs using a logging plugin. It does not affect connections made to the upstream Service or from downstream clients.

Default: TLSv1.1 TLSv1.2 TLSv1.3

lua_package_path

Sets the Lua module search path (LUA_PATH). Useful when developing or using custom plugins not stored in the default search path.

See https://github.com/openresty/lua-nginx-module#lua\_package\_path

Default: ./?.lua;./?/init.lua;

lua_package_cpath

Sets the Lua C module search path (LUA_CPATH).

See https://github.com/openresty/lua-nginx-module#lua\_package\_cpath

Default: none

lua_socket_pool_size

Specifies the size limit for every cosocket connection pool associated with every remote server.

See https://github.com/openresty/lua-nginx-module#lua\_socket\_pool\_size

Default: 30

enforce_rbac

Specifies whether Admin API RBAC is enforced.

Accepts one of entity, both, on, or off.

• on: only endpoint-level authorization is enforced.
• entity: entity-level authorization applies.
• both: enables both endpoint and entity-level authorization.
• off: disables both endpoint and entity-level authorization.

When enabled, Kong will deny requests to the Admin API when a nonexistent or invalid RBAC authorization token is passed, or the RBAC user with which the token is associated does not have permissions to access/modify the requested resource.

Default: off

rbac_auth_header

Defines the name of the HTTP request header from which the Admin API will attempt to authenticate the RBAC user.

Default: Kong-Admin-Token

event_hooks_enabled

When enabled, event hook entities represent a relationship between an event (source and event) and an action (handler). Similar to web hooks, event hooks can be used to communicate Kong Gateway service events. When a particular event happens on a service, the event hook calls a URL with information about that event. Event hook configurations differ depending on the handler. The events that are triggered send associated data.

See: https://docs.konghq.com/gateway/latest/admin-api/event-hooks/reference/

Default: on

Kong Manager section

The Admin GUI for Kong Enterprise.

admin_gui_listen

Kong Manager Listeners

Comma-separated list of addresses and ports on which Kong will expose Kong Manager. This web application lets you configure and manage Kong, and therefore should be kept secured.

Suffixes can be specified for each pair, similarly to the admin_listen directive.

Default: 0.0.0.0:8002, 0.0.0.0:8445 ssl

admin_gui_url

Kong Manager URL

The lookup, or balancer, address for Kong Manager.

Accepted format (items in parentheses are optional):

<scheme>://<IP / HOSTNAME>(:<PORT>(/<PATH>))

Examples:

• http://127.0.0.1:8003
• https://kong-admin.test
• http://dev-machine/dev-285

By default, Kong Manager will use the window request host and append the resolved listener port depending on the requested protocol.

Default: none

admin_gui_ssl_cert

The absolute path to the SSL certificate for admin_gui_listen values with SSL enabled.

Default: none

admin_gui_ssl_cert_key

The absolute path to the SSL key for admin_gui_listen values with SSL enabled.

Default: none

admin_gui_flags

Alters the layout Admin GUI (JSON) The only supported value is { "IMMUNITY_ENABLED": true } to enable Kong Immunity in the Admin GUI.

Default: {}

admin_gui_access_log

Kong Manager Access Logs

Here you can set an absolute or relative path for Kong Manager access logs. When the path is relative, logs are placed in the prefix location.

Setting this value to off disables access logs for Kong Manager.

Default: logs/admin_gui_access.log

admin_gui_error_log

Kong Manager Error Logs

Here you can set an absolute or relative path for Kong Manager access logs. When the path is relative, logs are placed in the prefix location.

Setting this value to off disables error logs for Kong Manager.

Granularity can be adjusted through the log_level directive.

Default: logs/admin_gui_error.log

admin_gui_auth

Kong Manager Authentication Plugin Name

Secures access to Kong Manager by specifying an authentication plugin to use.

Supported Plugins:

• basic-auth: Basic Authentication plugin
• ldap-auth-advanced: LDAP Authentication plugin
• openid-connect: OpenID Connect Authentication plugin

Default: none

admin_gui_auth_conf

Kong Manager Authentication Plugin Config (JSON)

Specifies the configuration for the authentication plugin specified in admin_gui_auth.

For information about Plugin Configuration consult the associated plugin documentation.

Example for basic-auth:

admin_gui_auth_conf = { "hide_credentials": true }

Default: none

admin_gui_auth_password_complexity

Kong Manager Authentication Password Complexity (JSON)

When admin_gui_auth = basic-auth, this property defines the rules required for Kong Manager passwords. Choose from preset rules or write your own.

Example using preset rules:

admin_gui_auth_password_complexity = { "kong-preset": "min_8" }

All values for kong-preset require the password to contain characters from at least three of the following categories:

1. Uppercase characters (A through Z)

2. Lowercase characters (a through z)

3. Base-10 digits (0 through 9)

4. Special characters (for example, &, $, #, %)

Supported preset rules:

• min_8: minimum length of 8
• min_12: minimum length of 12
• min_20: minimum length of 20

To write your own rules, see https://manpages.debian.org/jessie/passwdqc/passwdqc.conf.5.en.html.

NOTE: Only keywords “min”, “max” and “passphrase” are supported.

Example:

admin_gui_auth_password_complexity = { "min": "disabled,24,11,9,8" }

Default: none

admin_gui_session_conf

Kong Manager Session Config (JSON)

Specifies the configuration for the Session plugin as used by Kong Manager.

For information about plugin configuration, consult the Kong Session plugin documentation.

Example:

admin_gui_session_conf = { "cookie_name": "kookie", \
                            "secret": "changeme" }

Default: none

admin_gui_auth_header

Defines the name of the HTTP request header from which the Admin API will attempt to identify the Kong Admin user.

Default: Kong-Admin-User

admin_gui_auth_login_attempts

Number of times a user can attempt to login to Kong Manager. 0 means infinite attempts allowed.

Default: 0

admin_gui_header_txt

Sets custom text for the Kong Manager header banner.

Accepts any string. The header banner is not shown if this config entry is empty.

Default: none

admin_gui_header_bg_color

Sets the background color for the Kong Manager header banner. Accepts CSS color keyword, #-hexadecimal, or RGB format. Invalid values are ignored by Manager.

Default: none

admin_gui_header_txt_color

Sets the text color for the Kong Manager header banner. Accepts CSS color keyword, #-hexadecimal, or RGB format. Invalid values are ignored by Manager.

Default: none

admin_gui_footer_txt

Sets custom text for Kong Manager footer banner.

Accepts any string. The footer banner is not shown if this config entry is empty.

Default: none

admin_gui_footer_bg_color

Sets the background color for the Kong Manager footer banner. Accepts CSS color keyword, #-hexadecimal, or RGB format. Invalid values are ignored by Manager.

Default: none

admin_gui_footer_txt_color

Sets the text color for the Kong Manager footer banner. Accepts CSS color keyword, #-hexadecimal, or RGB format. Invalid values are ignored by Manager.

Default: none

admin_gui_login_banner_title

Sets custom title text for the Kong Manager login banner. Accepts any string.

The login banner is not shown if both admin_gui_login_banner_title and admin_gui_login_banner_body are empty.

Default: none

admin_gui_login_banner_body

Sets custom body text for the Kong Manager login banner. Accepts any string.

The login banner is not shown if both admin_gui_login_banner_title and admin_gui_login_banner_body are empty.

Default: none

Vitals section

vitals

When enabled, Kong will store and report metrics about its performance.

When running Kong in a multi-node setup, vitals entails two separate meanings depending on the node.

On a Proxy-only node, vitals determines whether to collect data for Vitals.

On an Admin-only node, vitals determines whether to display Vitals metrics and visualizations on the dashboard.

Default: on

vitals_strategy

Determines whether to use the Kong database (either PostgreSQL or Cassandra, as defined by the database config value above), or a separate storage engine, for Vitals metrics.

Accepted values are database, prometheus, or influxdb.

Default: database

vitals_tsdb_address

Defines the host and port of the TSDB server to which Vitals data is written and read.

This value is only applied when the vitals_strategy option is set to prometheus or influxdb. This value accepts IPv4, IPv6, and hostname values.

If the vitals_strategy is set to prometheus, this value determines the address of the Prometheus server from which Vitals data will be read. For influxdb strategies, this value controls both the read and write source for Vitals data.

Default: none

vitals_tsdb_user

Influxdb user

Default: none

vitals_tsdb_password

Influxdb password

Default: none

vitals_statsd_address

Defines the host and port (and an optional protocol) of the StatsD server to which Kong should write Vitals metics. This value is only applied when the vitals_strategy is set to prometheus. This value accepts IPv4, IPv6, and, hostnames. Additionally, the suffix tcp can be specified; doing so will result in Kong sending StatsD metrics via TCP instead of the UDP (default).

Default: none

vitals_statsd_prefix

Defines the prefix value attached to all Vitals StatsD events. This prefix is useful when writing metrics to a multi-tenant StatsD exporter or server.

Default: kong

vitals_statsd_udp_packet_size

This value is defined in bytes.

Default: 1024

vitals_prometheus_scrape_interval

Defines the scrape_interval query parameter sent to the Prometheus server when reading Vitals data.

This should be same as the scrape interval (in seconds) of the Prometheus server.

Default: 5

portal

Developer Portal on/off switch.

When enabled, Kong exposes the Dev Portal interface and read-only APIs on the portal_gui_listen address, and endpoints on the Admin API to manage assets.

When enabled along with portal_auth, Kong exposes management endpoints for developer accounts on the Admin API and the Dev Portal API.

Default: off

portal_gui_listen

Developer Portal GUI listeners.

Comma-separated list of addresses on which Kong exposes the Developer Portal GUI. Suffixes can be specified for each pair, similar to the admin_listen directive.

Default: 0.0.0.0:8003, 0.0.0.0:8446 ssl

portal_gui_protocol

Developer Portal GUI protocol.

The protocol used in conjunction with portal_gui_host to construct the lookup, or balancer address, for your Kong Proxy nodes.

Examples: http,https

Default: http

portal_gui_host

Developer Portal GUI host.

The host used in conjunction with portal_gui_protocol to construct the lookup, or balancer address, for your Kong Proxy nodes.

Examples:

• <IP>:<PORT> -> portal_gui_host = 127.0.0.1:8003
• <HOSTNAME> -> portal_gui_host = portal_api.domain.tld
• <HOSTNAME>/<PATH> -> portal_gui_host = dev-machine/dev-285

Default: 127.0.0.1:8003

portal_cors_origins

Developer Portal CORS origins.

A comma separated list of allowed domains for Access-Control-Allow-Origin header. This can be used to resolve CORS issues in custom networking environments.

Examples:

• list of domains: portal_cors_origins = http://localhost:8003, https://localhost:8004
• single domain: portal_cors_origins = http://localhost:8003
• all domains: portal_cors_origins = *

NOTE: In most cases, the Developer Portal is able to derive valid CORS origins by using portal_gui_protocol, portal_gui_host, and if applicable, portal_gui_use_subdomains. In these cases, portal_cors_origins is not needed and can remain unset.

Default: none

portal_gui_use_subdomains

Developer Portal GUI subdomain toggle.

By default, Dev Portal uses the first namespace in the request path to determine workspace. By turning portal_gui_subdomains on, Dev Portal will expect a workspace to be included in the request URL as a subdomain.

Example (off): - <scheme>://<HOSTNAME>/<WORKSPACE>/<PATH> -> http://kong-portal.com/example-workspace/index

Example (on): - <scheme>://<WORKSPACE>.<HOSTNAME> -> http://example-workspace.kong-portal.com/index

Default: off

portal_gui_ssl_cert

Developer Portal GUI SSL certificate.

The absolute path to the SSL certificate for portal_gui_listen values with SSL enabled.

Default: none

portal_gui_ssl_cert_key

Developer Portal GUI SSL certificate key.

The absolute path to the SSL key for portal_gui_listen values with SSL enabled.

Default: none

portal_gui_access_log

Developer Portal GUI access log location.

An absolute or relative path for your Portal GUI access logs.

Setting this value to off disables logging Portal GUI access logs.

When using relative pathing, logs will be placed under the prefix location.

Default: logs/portal_gui_access.log

portal_gui_error_log

Developer Portal GUI error log location.

An absolute or relative path for your Portal GUI error logs.

Setting this value to off disables logging Portal GUI error logs.

When using relative pathing, logs will be placed under the prefix location.

Granularity can be adjusted through the log_level directive.

Default: logs/portal_gui_error.log

portal_api_listen

Developer Portal API listeners.

Comma-separated list of addresses on which Kong exposes the Developer Portal API. Suffixes can be specified for each pair, similarly to the admin_listen directive.

Default: 0.0.0.0:8004, 0.0.0.0:8447 ssl

portal_api_url

Developer Portal API URL.

The lookup, or balancer, address for your Developer Portal nodes.

This value is commonly used in a microservices or service-mesh oriented architecture.

portal_api_url is the address on which your Kong Dev Portal API is accessible by Kong. You should only set this value if your Kong Dev Portal API lives on a different node than your Kong Proxy.

Accepted format (parts in parentheses are optional):

<scheme>://<IP / HOSTNAME>(:<PORT>(/<PATH>))

Examples:

• <scheme>://<IP>:<PORT> -> portal_api_url = http://127.0.0.1:8003
• SSL <scheme>://<HOSTNAME> -> portal_api_url = https://portal_api.domain.tld
• <scheme>://<HOSTNAME>/<PATH> -> portal_api_url = http://dev-machine/dev-285

By default this value points to the local interface:

• http://0.0.0.0:8004

Default: none

portal_api_ssl_cert

Developer Portal API SSL certificate.

The absolute path to the SSL certificate for portal_api_listen values with SSL enabled.

Default: none

portal_api_ssl_cert_key

Developer Portal API SSL certificate key.

The absolute path to the SSL key for portal_api_listen values with SSL enabled.

Default: none

portal_api_access_log

Developer Portal API access log location.

An absolute or relative path for your Portal API access logs.

Setting this value to off disables logging Portal API access logs.

When using relative pathing, logs will be placed under the prefix location.

Default: logs/portal_api_access.log

portal_api_error_log

Developer Portal API error log location.

An absolute or relative path for your Portal API error logs.

Setting this value to off disables logging Portal API error logs.

When using relative pathing, logs will be placed under the prefix location.

Granularity can be adjusted through the log_level directive.

Default: logs/portal_api_error.log

portal_is_legacy

Developer Portal legacy support.

You can set this value to on or off.

• on: causes all new portals to render using the legacy rendering system by default.

• off: causes all new portals to render using the current rendering system.

Default: off

portal_app_auth

Developer Portal application registration auth provider and strategy. Must be set to enable the application-registration plugin.

Accepts kong-oauth2 or external-oauth2.

Default: kong-oauth2

Default Developer Portal Authentication section

Referenced on workspace creation to set Dev Portal authentication defaults in the database for that particular workspace.

portal_auth

Developer Portal authentication plugin name.

Specifies the authentication plugin to apply to your Developer Portal. Developers will use the specified form of authentication to request access, register, and login to your Developer Portal.

Supported Plugins:

• Basic Authentication: portal_auth = basic-auth
• OIDC Authentication: portal_auth = openid-connect

Default: none

portal_auth_password_complexity

Dev Portal authentication password complexity, in JSON format.

When portal_auth = basic-auth, this property defines the rules required for Dev Portal passwords. Choose from preset rules or write your own.

Example using preset rules:

portal_auth_password_complexity = { "kong-preset": "min_8" }

All values for kong-preset require the password to contain characters from at least three of the following categories:

1. Uppercase characters (A through Z)

2. Lowercase characters (a through z)

3. Base-10 digits (0 through 9)

4. Special characters (for example, &, $, #, %)

Supported preset rules:

• min_8: minimum length of 8
• min_12: minimum length of 12
• min_20: minimum length of 20

To write your own rules, see .

NOTE: Only keywords “min”, “max” and “passphrase” are supported.

Example:

portal_auth_password_complexity = { "min": "disabled,24,11,9,8" }

Default: none

portal_auth_conf

Developer Portal Authentication Plugin Config (JSON)

Specifies the plugin configuration object in JSON format to be applied to your Developer Portal authentication.

For information about Plugin Configuration consult the associated plugin documentation.

Example for basic-auth:

portal_auth_conf = { "hide_credentials": true }

Default: none

portal_auth_login_attempts

Number of times a user can attempt to login to the Dev Portal before password must be reset.

0 (default) means infinite attempts allowed.

Note: Any value greater than 0 will only affect Dev Portals secured with basic-auth.

Default: 0

portal_session_conf

Portal Session Config (JSON)

Specifies the configuration for the Session plugin as used by Dev Portal.

For information about Plugin Configuration consult the Kong Session Plugin documentation.

Example:

portal_session_conf = { "cookie_name": "portal_session", \
                          "secret": "changeme", \
                          "storage": "kong" }

Default: none

portal_auto_approve

Developer Portal Auto Approve Access

When this flag is set to on, a developer will automatically be marked as “approved” after completing registration. Access can still be revoked through the Admin GUI or API.

Default: off

portal_token_exp

Duration in seconds for the expiration of portal login reset/account validation token.

Default: 21600

portal_email_verification

Portal Developer Email Verification.

When enabled Developers will receive an email upon registration to verify their account. Developers will not be able to use the Developer Portal until they verify their account.

Note: SMTP must be turned on in order to use this feature.

Default: off

Default Portal Smtp Configuration section

Referenced on workspace creation to set SMTP defaults in the database for that particular workspace.

portal_invite_email

Enable or disable portal_invite_email

Default: on

portal_access_request_email

Enable or disable portal_access_request_email

Default: on

portal_approved_email

Enable or disable portal_approved_email

Default: on

portal_reset_email

Enable or disable portal_reset_email

Default: on

portal_reset_success_email

Enable or disable portal_reset_success_email

Default: on

portal_emails_from

The name and email address for the From header for portal emails

Example: portal_emails_from = Your Name <example@example.com>

Note: Some SMTP servers will not use this value, but instead insert the email and name associated with the account.

Default: none

portal_emails_reply_to

Email address for the Reply-To header for portal emails

Example: portal_emails_reply_to = example@example.com

Note: Some SMTP servers will not use this value, but instead insert the email associated with the account.

Default: none

Admin Smtp Configuration section

admin_emails_from

The email address for the From header for admin emails.

Default: ""

admin_emails_reply_to

Email address for the Reply-To header for admin emails.

Default: none

admin_invitation_expiry

Expiration time for the admin invitation link (in seconds). 0 means no expiration.

Example, 72 hours: 72 * 60 * 60 = 259200

Default: 259200

General Smtp Configuration section

smtp_mock

This flag will mock the sending of emails. This can be used for testing before the SMTP client is fully configured.

Default: on

smtp_host

The hostname of the SMTP server to connect to.

Default: localhost

smtp_port

The port number on the SMTP server to connect to.

Default: 25

smtp_starttls

When set to on, STARTTLS is used to encrypt communication with the SMTP server. This is normally used in conjunction with port 587.

Default: off

smtp_username

Username used for authentication with SMTP server

Default: none

smtp_password

Password used for authentication with SMTP server

Default: none

smtp_ssl

When set to on, SMTPS is used to encrypt communication with the SMTP server. This is normally used in conjunction with port 465.

Default: off

smtp_auth_type

The method used to authenticate with the SMTP server Valid options are plain, login, or nil

Default: none

smtp_domain

The domain used in the EHLO connection and part of the Message-ID header

Default: localhost.localdomain

smtp_timeout_connect

The timeout (in milliseconds) for connecting to the SMTP server.

Default: 60000

smtp_timeout_send

The timeout (in milliseconds) for sending data to the SMTP server.

Default: 60000

smtp_timeout_read

The timeout (in milliseconds) for reading data from the SMTP server.

Default: 60000

smtp_admin_emails

Comma separated list of admin emails to receive notifications.

Example admin1@example.com, admin2@example.com

Default: none

Data & Admin Audit section

When enabled, Kong will store detailed audit data regarding Admin API and database access. In most cases, updates to the database are associated with Admin API requests. As such, database object audit log data is tied to a given HTTP via a unique identifier, providing built-in association of Admin API and database traffic.

audit_log

When enabled, Kong will log information about Admin API access and database row insertions, updates, and deletes.

Default: off

audit_log_ignore_methods

Comma-separated list of HTTP methods that will not generate audit log entries. By default, all HTTP requests will be logged.

Default: none

audit_log_ignore_paths

Comma-separated list of request paths that will not generate audit log entries. By default, all HTTP requests will be logged.

Default: none

audit_log_ignore_tables

Comma-separated list of database tables that will not generate audit log entries. By default, updates to all database tables will be logged (the term “updates” refers to the creation, update, or deletion of a row).

Default: none

audit_log_payload_exclude

Comma-separated list of keys that will be filtered out of the payload. Keys that were filtered will be recorded in the audit log.

Default: token, secret, password

audit_log_record_ttl

Length, in seconds, of the TTL for audit log records. Records in the database older than their TTL are automatically purged.

Example, 30 days: 30 * 24 * 60 * 60 = 2592000

Default: 2592000

audit_log_signing_key

Defines the path to a private RSA signing key that can be used to insert a signature of audit records, adjacent to the record. The corresponding public key should be stored offline, and can be used the validate audit entries in the future. If this value is undefined, no signature will be generated.

Default: none

Granular Tracing section

Granular tracing offers a mechanism to expose metrics and detailed debug data about the lifecycle of Kong in a human- or machine-consumable format.

tracing

When enabled, Kong will generate granular debug data about various portions of the request lifecycle, such as DB or DNS queries, plugin execution, core handler timing, etc.

Default: off

tracing_write_strategy

Defines how Kong will write tracing data at the conclusion of the request. The default option, file, writes a human-readable depiction of tracing data to a configurable location on the node’s file system. Other strategies write tracing data as a JSON document to the configured endpoint. Valid entries for this option are file, file_raw, http, tcp, tls, and udp.

Default: file

tracing_write_endpoint

Defines the endpoint to which tracing data will be written.

• For the file and file_raw tracing write strategies, this value must be a valid location on the node’s file system to which Kong must have write access.
• For the tcp, tls, and udp strategies, this value is defined as a string in the form of: <HOST>:<PORT>
• For the http strategy, this value is defined in the form of: <scheme>://<IP / HOSTNAME>(:<PORT>(/<PATH>))

Traces sent via HTTP are delivered via POST method with an application/json Content-Type.

Default: none

tracing_time_threshold

The minimum time, in microseconds, over which a trace must execute in order to write the trace data to the configured endpoint. This configuration can be used to lower the noise present in trace data by removing trace objects that are not interesting from a timing perspective. The default value of 0 removes this limitation, causing traces of any duration to be written.

Default: 0

tracing_types

Defines the types of traces that are written.

Trace types not defined in this list are ignored, regardless of their lifetime. The default special value of all results in all trace types being written, regardless of type.

The following trace types are included:

• query: trace the database query
• legacy_query: (deprecated) trace the database query with legacy DAO
• router: trace Kong routing the request; internal routing time
• balancer: trace the execution of the overall balancer phase
• balancer.getPeer: trace Kong selecting an upstream peer from the ring-balancer
• balancer.toip: trace balancer to resolve peer’s host to IP
• connect.toip: trace cosocket to resolve target’s host to IP
• access.before: trace the preprocessing of access phase, like parameter parsing, route matching, and balance preparation
• access.after: trace the postprocess of access phase, like balancer execution and internal variable assigning
• cassandra_iterate: trace Cassandra driver to paginate over results
• plugin: trace plugins phase handlers

Default: all

tracing_debug_header

Defines the name of the HTTP request header that must be present in order to generate traces within a request. Setting this value provides a mechanism to selectively generate request traces at the client’s request. Note that the value of the header does not matter, only that the header is present in the request. When this value is not set and tracing is enabled, Kong will generate trace data for all requests flowing through the proxy and Admin API. Note that data from certificate handling phases is not logged when this setting is enabled.

Default: none

generate_trace_details

When enabled, Kong will write context- specific details into traces. Trace details offer more data about the context of the trace. This can significantly increase the size of trace reports. Note also that trace details may contain potentially sensitive information, such as raw SQL queries; care should be taken to store traces properly when this option is enabled.

Default: off

Route Collision Detection/Prevention section

route_validation_strategy

The strategy used to validate routes when creating or updating them.

Different strategies are available to tune how to enforce splitting traffic of workspaces.

• smart is the default option and uses the algorithm described in https://docs.konghq.com/gateway/latest/admin-api/workspaces/examples/#important-note-conflicting-services-or-routes-in-workspaces
• off disables any check
• path enforces routes to comply with the pattern described in config enforce_route_path_pattern

Default: smart

enforce_route_path_pattern

Specifies the Lua pattern which will be enforced on the paths attribute of a Route object. You can also add a placeholder for the workspace in the pattern, which will be rendered during runtime based on the workspace to which the route belongs.

This setting is only relevant if route_validation_strategy is set to path.

Example For Pattern /$(workspace)/v%d/.* valid paths are:

1. /group1/v1/ if route belongs to workspace group1.

2. /group2/v1/some_path if route belongs to workspace group2.

Default: none

When enabled, Kong will transparently encrypt sensitive fields, such as Consumer credentials, TLS private keys, and RBAC user tokens, among others. A full list of encrypted fields is available from the Kong Enterprise documentation site.

Encrypted data is transparently decrypted before being displayed to the Admin API or made available to plugins or core routing logic.

While this feature is GA, do note that we currently do not provide normal semantic versioning compatibility guarantees on the keyring feature’s APIs in that Kong may make a breaking change to the feature in a minor version. Also note that mis-management of keyring data may result in irrecoverable data loss.

keyring_enabled

When enabled, Kong will encrypt sensitive field values before writing them to the database, and subsuquently decrypt them when retrieving data for the Admin API, Developer Portal, or proxy business logic. Symmetric encryption keys are managed based on the strategy defined below.

Default: off

keyring_strategy

Defines the strategy implementation by which Kong nodes will manage symmetric encryption keys. Please see the Kong Enterprise documentation for a detailed description of each strategies. Acceptable values for this option are ‘cluster’ and ‘vault’.

Default: cluster

keyring_public_key

Defines the filesystem path at which the public key of an RSA keypair resides. This keypair is used for symmetric keyring import/ export, e.g., for disaster recovery and optional bootstrapping.

Default: none

keyring_private_key

Defines the filesystem path at which the private key of an RSA keypair resides. This keypair is used for symmetric keyring import/ export, e.g., for disaster recovery and optional bootstrapping.

Default: none

keyring_blob_path

Defines the filesystem path at which Kong will backup the initial keyring material.

This option is useful largely for development purposes.

Default: none

keyring_vault_host

Defines the Vault host at which Kong will fetch the encryption material. This value should be defined in the format:

<scheme>://<IP / HOSTNAME>:<PORT>

Default: none

keyring_vault_mount

Defines the name of the Vault v2 KV secrets engine at which symmetric keys are found.

Default: none

keyring_vault_path

Defines the names of the Vault v2 KV path at which symmetric keys are found.

Default: none

keyring_vault_token

Defines the token value used to communicate with the v2 KV Vault HTTP(S) API.

Default: none

untrusted_lua

Controls loading of Lua functions from admin-supplied sources such as the Admin API. LuaJIT bytecode loading is always disabled.

Warning: LuaJIT is not designed as a secure runtime for running malicious code, therefore you should properly protect your Admin API endpoint even with sandboxing enabled. The sandbox only provides protection against trivial attackers or unintentional modification of the Kong global environment.

Accepted values are: off, sandbox, or on:

• off: Disallow loading of any arbitrary Lua functions. The off option disables any functionality that runs arbitrary Lua code, including the Serverless Functions plugins and any transformation plugin that allows custom Lua functions.

• sandbox: Allow loading of Lua functions, but use a sandbox when executing them. The sandboxed function has restricted access to the global environment and only has access to standard Lua functions that will generally not cause harm to the Kong Gateway node.

• on: Functions have unrestricted access to the global environment and can load any Lua modules. This is similar to the behavior in Kong Gateway prior to 2.3.0.

The default sandbox environment does not allow importing other modules or libraries, or executing anything at the OS level (for example, file read/write). The global environment is also not accessible.

Examples of untrusted_lua = sandbox behavior:

• You can’t access or change global values such as kong.configuration.pg_password * You can run harmless lua: local foo = 1 + 1. However, OS level functions are not allowed, like: os.execute('rm -rf /*').

For a full allowed/disallowed list, see: https://github.com/kikito/sandbox.lua/blob/master/sandbox.lua

To customize the sandbox environment, use the untrusted_lua_sandbox_requires and untrusted_lua_sandbox_environment parameters below.

Default: sandbox

untrusted_lua_sandbox_requires

Comma-separated list of modules allowed to be loaded with require inside the sandboxed environment. Ignored if untrusted_lua is not sandbox.

For example, say you have configured the Serverless pre-function plugin and it contains the following requires:

To run the plugin, add the modules to the allowed list:

untrusted_lua_sandbox_requires = resty.template, kong.tools.utils

Warning: Allowing certain modules may create opportunities to escape the sandbox. For example, allowing os or luaposix may be unsafe.

Default: none

untrusted_lua_sandbox_environment

Comma-separated list of global Lua variables that should be made available inside the sandboxed environment. Ignored if untrusted_lua is not .

Warning: Certain variables, when made available, may create opportunities to escape the sandbox.