Configuration

Description

cluster.proto_dist

Description

Distributed Erlang cluster protocol type. Available values are:

• inet_tcp: using IPv4
• inet6_tcp: using IPv6
• inet_tls: using TLS, required to be used with node.ssl_dist_optfile configuration

cluster.discovery

Description

Cluster node discovery method. Available values are:

• manual: join the cluster manually
• static: Configure static nodes. Configure several fixed nodes, and the new node joins the cluster by connecting one of the fixed nodes.
• mcast: Use UDP multicast to discover nodes.
• dns: Use DNS A records to discover nodes.
• etcd: Use etcd to discover nodes.
• k8s: Use Kubernetes to discover nodes.

cluster.autoheal

Description

Enable or disable the automatic recovery mechanism for cluster network partitions.

cluster.autoclean

Description

Specify how long to delete offline nodes from the cluster.

cluster.static.seeds

Description

When using static clustering, specify a fixed list of nodes, separated by commas , between multiple nodes.

cluster.mcast.addr

Description

When using the mcast cluster, specify the multicast address.

cluster.mcast.ports

Description

When using the mcast cluster, specify the multicast port. If there are multiple ports, separate them with commas ,.

cluster.mcast.iface

Description

When using mcast cluster, specify which local IP address the node discovery service needs to bind to.

cluster.mcast.ttl

Description

When using mcast cluster, specify the Time-To-Live value of multicast.

cluster.mcast.loop

Description

When using mcast clustering, set whether multicast packets are delivered to the local loopback address.

cluster.dns.name

Description

When using the dns cluster, specify the name of the DNS A record. emqx will access the DNS A record to obtain a list of IP addresses, and then splice the APP name specified in cluster.dns.app to get a list of all nodes in the cluster.

Example

Set cluster.dns.app = emqx, and configure a DNS: mycluster.com, which points to 3 IP addresses:

Then get the list of cluster nodes as follows:

emqx@192.168.0.100
emqx@192.168.0.101
emqx@192.168.0.102

cluster.dns.app

Description

When using dns cluster, it is used to splice the IP list obtained from cluster.dns.name to get a list of node names.

cluster.etcd.server

Description

When using etcd cluster, specify the address of etcd service. If there are multiple services, use commas to separate them.

cluster.etcd.prefix

Description

When using etcd cluster, specify the prefix of etcd path. Each node creates a path in etcd:

v2/keys/<prefix>/<cluster.name>/<node.name>

cluster.etcd.node_ttl

Description

When using etcd cluster, specify the expiration time of the node path in etcd.

cluster.etcd.ssl.keyfile

Description

When using SSL to connect to etcd, specify the client’s private key file.

cluster.etcd.ssl.certfile

Description

When using SSL to connect to etcd, specify the SSL client certificate file.

cluster.etcd.ssl.cacertfile

Description

When using SSL to connect to etcd, specify the CA certificate file for SSL.

cluster.k8s.apiserver

Description

When using the k8s cluster, specify the Kubernetes API Server. If there are multiple Servers, separate them with commas ,.

cluster.k8s.service_name

Description

When using k8s cluster, specify the service name of EMQX Broker in Kubernetes.

cluster.k8s.address_type

Description

When using k8s cluster, address_type is used to obtain the host list from the response of the Kubernetes interface.

Example

Specifying cluster.k8s.address_type as ip, it will get the list of IP addresses of emqx services from the Kubernetes interface:

172.16.122.31
172.16.122.32
172.16.122.33

Then splice with the app name specified by cluster.k8s.app_name configuration to get a list of emqx nodes:

emqx@172.16.122.31
emqx@172.16.122.32
emqx@172.16.122.33

cluster.k8s.app_name

Description

When using k8s clustering, app_name is used to splice with the obtained Host list to get the node list.

cluster.k8s.suffix

Description

When using the k8s method and specifying cluster.k8s.address_type as the dns type, you can set the suffix of the emqx node name, and splice with cluster.k8s.namespace to get a list of node names.

cluster.k8s.namespace

Description

When using the k8s method and specifying cluster.k8s.address_type as the dns type, you can set the namespace of the emqx node name, and splice with cluster.k8s.suffix to get a list of node names.

Example

Setting cluster.k8s.address_type to dns, you will get the dns list of emqx service from the Kubernetes interface:

172-16-122-31
172-16-122-32
172-16-122-33

Then splice with cluster.k8s.app_name = emqx，cluster.k8s.suffix = pod.cluster.local，cluster.k8s.namespace = default to get a list of emqx node names in the form of dns:

emqx@172-16-122-31.default.pod.cluster.local
emqx@172-16-122-32.default.pod.cluster.local
emqx@172-16-122-33.default.pod.cluster.local

node.name

Description

The node name. The format is <name> @ <host>. Where <host> can be an IP address or FQDN. See http://erlang.org/doc/reference_manual/distributed.html (opens new window) for details

node.cookie

Description

The cookie value used by the distributed Erlang cluster.

node.data_dir

Description

The node’s data directory, which is used to store Mnesia data files.

node.heartbeat

Description

System tuning parameters. This configuration will override the -heart parameter in the vm.args file.

Enable or disable Erlang runtime detection mechanism, and restart automatically when the runtime terminates. Use with care to avoid restarting the monitored process when emqx is closed manually.

node.async_threads

Description

System tuning parameters. This configuration will override the +A parameter in the vm.args file.

Set the number of threads in the asynchronous thread pool in Erlang runtime, see for details.

node.process_limit

Description

System tuning parameters. This configuration will override the +P parameter in the vm.args file.

Set the maximum number of processes allowed by Erlang, which will affect the number of connections that emqx nodes can process. See http://erlang.org/doc/man/erl.html (opens new window) for details.

node.max_ports

Description

System tuning parameters. This configuration will override the +Q parameter in the vm.args file.

Set the maximum number of ports allowed by Erlang. See for details.

node.dist_buffer_size

Description

System tuning parameters. This configuration will override the +zdbbl parameter in the vm.args file.

Set the maximum cache size used by Erlang distributed communication. See http://erlang.org/doc/man/erl.html (opens new window) for details.

node.max_ets_tables

Description

System tuning parameters. This configuration will override the +e parameter in the vm.args file.

Set the maximum number of ETS tables allowed in Erlang runtime. See for details.

node.global_gc_interval

Description

System tuning parameters, which set how often Erlang runs to force a global garbage collection.

node.fullsweep_after

Description

System tuning parameters. This configuration will override the -env ERL_FULLSWEEP_AFTER parameter in the vm.args file.

Set how many times the generational GC will run before Erlang runs a fullsweep GC. For details, see http://erlang.org/doc/man/erlang.html#spawn_opt-4 (opens new window).

node.crash_dump

Description

Set the storage path and file name of the Erlang crash_dump file.

node.ssl_dist_optfile

Description

This configuration will override the -ssl_dist_optfile parameter in the vm.args file.

If you use SSL to establish an emqx cluster, you need to specify the SSL distributed protocol configuration file. It needs to be used with cluster.proto_dist = inet_tls.

node.dist_net_ticktime

Description

System tuning parameters. This configuration will override the -kernel net_ticktime parameter in the vm.args file.

Specifying how long time when a node has been unresponsive, it is considered to be down and disconnected. For details, see .

node.dist_use_interface

Description

The default is to use 0.0.0.0 to specify all network-interfaces to listen to, or to specify the IP of the network-interface to listen to.

node.dist_listen_min

Description

Set a TCP port range together with node.dist_listen_max. This port ranget is used for distribution to distributed Erlang as a listening port for distributed channels. Note that if a firewall is set between nodes, this port range needs to be placed into the firewall’s whitelist.

node.dist_listen_max

Description

Set a TCP port range together with node.dist_listen_min. This port range is used for distribution to distributed Erlang as a listening port for distributed channels. Note that if a firewall is set up between nodes, this port rangeneeds to be put in The firewall’s whitelist.

rpc.mode

Description

RPC mode. Synchronous or asynchronous mode is optional.

rpc.async_batch_size

Description

The maximum number of batch messages sent in asynchronous mode. Note that this configuration does not work in synchronous mode.

rpc.port_discovery

Description

manual: discover ports by tcp_server_port and tcp_client_port. stateless: discover ports in a stateless manner. If node name is emqx<N>@127.0.0.1, where the <N> is an integer, then the listening port will be 5370 + <N>

Default is manual when started from docker (environment variable override from docker-entrypoint) otherwise stateless.

rpc.tcp_server_ip

Description

Set the listening network-interface used by RPC local service. Use 0.0.0.0 to listen to all network-interfaces. NOTE: this config only takes effect when rpc.port_discovery is set to manual

rpc.tcp_server_port

Description

Set the listening port used by RPC local service NOTE: this config only takes effect when rpc.port_discovery is set to manual

rpc.tcp_client_num

Description

Set the number of RPC communication channels initiated by this node to each remote node. Set to 1 to ensure the order of messages. Keep the default value (half the number of CPU cores) to improve RPC throughput.

rpc.driver

Description

Transport-layer protocol used for communication between the brokers.

rpc.default_client_driver

Description

Transport-layer protocol used for communication between the brokers (client side). This parameter should match the value of rpc.driver.

rpc.enable_ssl

Description

Listening port used by RPC local service. Note that this config only takes effect when rpc.port_discovery is set to manual and driver is set to ssl.

rpc.certfile

Description

Path to TLS certificate file used to validate identity of the cluster nodes. This configuration is mandatory when rpc.driver is set to ssl, otherwise it doesn’t take any effect.

rpc.cacertfile

Description

Path to certification authority TLS certificate file used to validate rpc.certfile. This configuration is mandatory when rpc.driver is set to ssl, otherwise it doesn’t take any effect.

rpc.keyfile

Description

Path to the private key file for the rpc.certfile. This configuration is mandatory when rpc.driver is set to ssl, otherwise it doesn’t take any effect. Note: contents of this file are secret, so it’s necessary to set permissions to 600.

rpc.connect_timeout

Description

Timeout for establishing an RPC connection. It means how long will it give up after trying if the remote node does not respond when establishing a connection, .

rpc.send_timeout

Description

Timeout for sending, which means how long to give up after sending the message.

rpc.authentication_timeout

Description

RPC authentication timeout. It means how long it will give up if the remote node does not respond, .

rpc.call_receive_timeout

Description

The timeout period of RPC synchronous mode. It means how long it will take before giving up if the RPC synchronous call fails to receive a reply.

rpc.socket_keepalive_idle

Description

It means how long after the last packet was sent, keepalive probe packets are sent.

rpc.socket_keepalive_interval

Description

The interval between keepalive detection messages.

rpc.socket_keepalive_count

Description

For how many times if the keepalive probe message fails to receive a reply, the RPC connection is considered lost.

rpc.socket_sndbuf

Description

TCP tuning parameters. TCP sending buffer size.

rpc.socket_recbuf

Description

TCP tuning parameters. TCP receiving buffer size.

rpc.socket_buffer

Description

TCP tuning parameters. Socket buffer size in user mode.

log.to

Description

Where to output the log. The optional values are:

• off: Disable logging completely
• file: Only output log to file
• console: Only output logs to standard output (emqx console)
• both: output log to file and standard output at the same time (emqx console)

log.level

Description

Global log level. This includes the primary log level and all log handlers. For details, see log level and log handlers.

log.dir

Description

Log file directory.

log.file

Description

The prefix of the log file. For example, if you use the default value (log.file = emqx.log), the log file name will be emqx.log.1, emqx.log.2, …

log.chars_limit

Description

Set the maximum length of a single log message. If this length is exceeded, the log message will be truncated. -1 means no limit.

log.max_depth

Description

Maximum depth for Erlang term log formatting and Erlang process message queue inspection. Set ‘unlimited’ (without quotes) to print Erlang terms without depth limit.

log.rotation.size

Description

Set the size of a single log file. If it exceeds this size, the log file will be rolled to create a new log file.

log.rotation.count

Description

Set the total number of log files. If this number is exceeded, the next log file will overwrite the first file.

log.<level>.file

Description

Set a separate log file for a certain log level.

Example

Separately output info and above logs to info.log.N file:

log.info.file = info.log

Output error and error logs separately to the error.log.N file

log.error.file = error.log

log.max_depth

Description

Max depth when printing large data blob to log. Exceeding parts will be logge as ‘…’.

log.single_line

Description

Print logs in a single line if set to true. If set to false, information like stacktraces in crash logs may span multiple lines.

log.formatter

Description

Choose log format. text for free text, and json for structured logging.

log.formatter.text.date.format

NOTE: This config is available start from EMQX Opensource 4.3.15, 4.4.4 and EMQX Enterprise 4.3.10, 4.4.4.

Description

The timestamp format for the text logger. Can be one of rfc3339 or a FORMAT string.

Supported specifiers in the FORMAT string are:

Examples:

authacl

allow_anonymous

Description

Whether to allow anonymous users to log in to the system.

Tip

It is recommended to disable this option in the production environment.

acl_nomatch

Description

When the ACL is not hit, allow or deny the publish/subscribe operation.

acl_file

Description

The default path of ACL file.

enable_acl_cache

Description

Whether to enable ACL caching.

acl_cache_max_size

Description

Maximum cache number of ACL rule.

acl_cache_ttl

Description

Maximum cache time of ACL rule.

acl_deny_action

Description

What to do after the ACL check fails.

• ignore：No operation
• disconnect：disconnect.

acl_order

Description

When using multiple ACL backends, this config can be used to define their order. The default value none means no explicit ordering, in which case the order depends on the plugin (or module) start/restart order. Use comma to separate the names (or aliases), for example jwt,http means jwt authentication should be checked before http. Supported aliases are: internal (or file), http, jwt, ldap, mnesia, mongo (or mongodb), mysql, pgsql (or postgres), redis. It is not necessary to enumerate all the in-use ACL backends here, if only a part of the backends are listed here, the ones not listed will be ordered at the end. When using a third-party plugin, there is no alias support for it, so it has to be the specific callback module name, e.g. my_auth_plugin_module.

Tip

Unknown names are silently discarded.

auth_order

Description

When using multiple authentication backends, this config can be used to define their order. This config is similar to acl_order, only there is no internal authentication backend.

Tip

Unknown names are silently discarded.

alias_enrichment_module

Description

Tip

This is a very specific, advanced option that should not be used unless recommended by EMQ.

Introduced in 4.4.11.

Specify a module that defines the enrich_with_aliases/2 function. This function will be used to enrich the client/channel information with clientid and/or common name aliases (or other enrichments the module may implement).

special_auth_module

Description

Tip

This is a very specific, advanced option that should not be used unless recommended by EMQ.

Introduced in 4.4.11.

Specify a module that defines the check_authn/2 function. This function will be used in the client.authenticate hook as a way to implement custom authentication logic.

mqtt

flapping_detect_policy

Description

Specify the Flapping inspection strategy.

Format: <threshold>,<duration>,<banned>.

For example, 30, 1m, 5m, it means that if the client disconnects 30 times within 1 minute, then login is prohibited for the next 5 minutes

mqtt.max_packet_size

Description

The maximum allowed length of MQTT messages.

mqtt.max_clientid_len

Description

The maximum allowed length of Client ID string.

mqtt.max_topic_levels

Description

The maximum allowed level of topics for client subscription. 0 means no limit.

Warning

Too many topic levels may cause performance problems during subscription.

mqtt.max_qos_allowed

Description

The maximum allowed QoS level for client to publish.

mqtt.max_topic_alias

Description

The maximum allowed number of topic aliases. 0 means that topic aliases are not supported.

mqtt.retain_available

Description

Whether to support Retain message.

mqtt.wildcard_subscription

Description

Whether to support subscribing to wildcard topics.

mqtt.shared_subscription

Description

Whether to support shared subscriptions.

mqtt.ignore_loop_deliver

Description

Whether to ignore the message sent by itself. If it is ignored, it means that EMQX Broker will not deliver this message to the sender of the message.

mqtt.strict_mode

Description

Whether to enable the strict check mode. The strict check mode will check the correctness of the MQTT message in more detail.

zone.external.idle_timeout

Description

The daze time after the TCP connection is established. If no packets are received within this time, the connection will be shutdown.

zone.external.enable_acl

Description

Whether to enable ACL check.

zone.external.enable_ban

Description

Whether to enable blacklist.

zone.external.enable_stats

Description

Whether to enable client status statistics.

zone.external.acl_deny_action

| Type | Optional Value | Default | | —— | —————————— - | ———— | | enum | ignore, disconnect | ignore |

Description

What to do after the ACL check fails.

• ignore：No any operation.
• disconnect：disconnect.

zone.external.force_gc_policy

Description

When a certain number of messages, or bytes, are received, a garbage collection is forced.

Format: <Number> | <Bytes>.

For example, 16000|16MB means that when 16000 messages are received, or a byte of 16MB flows in, a garbage collection is forced.

zone.external.force_shutdown_policy

Description

When the process message queue length, or the memory bytes reaches a certain value, the process is forced to close.

The “message queue” here refers to the “message mailbox” of the Erlang process, not the “mqueue” of QoS 1 and QoS 2.

Format: <Number> | <Bytes>.

For example, 32000|32MB means that when the process accumulates 32000 messages, or the process occupies memory up to 32MB, the process is closed.

zone.external.max_packet_size

Description

The maximum allowed length of MQTT packet.

zone.external.max_clientid_len

Description

The maximum length of Client ID string.

zone.external.max_topic_levels

Description

The maximum allowed level of topics for client subscription. 0 means no limit.

Warning

Too many topic levels may cause performance problems during subscription.

zone.external.max_qos_allowed

Description

The maximum QoS level allowed for the client to publish.

zone.external.max_topic_alias

Description

The maximum number of topic aliases. 0 means that topic aliases are not supported.

zone.external.retain_available

Description

Whether to support Retain message.

zone.external.wildcard_subscription

Description

Whether to support subscribing to wildcard topics.

zone.external.shared_subscription

Description

Whether to support shared subscriptions.

zone.external.server_keepalive

Description

Keepalive time specified by the server, used for MQTT v5.0 CONNACK messages

zone.external.keepalive_backoff

Description

Keepalive backoff index. If no data packet is received from the client within the time of Keepalive * backoff * 2, it is considered that the client has heartbeat timeout.

zone.external.max_subscriptions

Description

The maximum number of topics that a single client is allowed to subscribe to. 0 means no limit.

zone.external.upgrade_qos

Description

Allow EMQX Broker to force the QoS level of the message upgrading to the subscribed QoS level when publishing the message.

zone.external.max_inflight

Description

Inflight window size: The inflight window is used to store unacknowledged QoS 1 and QoS 2 messages.

zone.external.retry_interval

Description

Message retransmission interval: EMQX Broker checks whether message retransmission is required at each interval.

zone.external.max_awaiting_rel

Description

The maximum receiving window for QoS 2 messages, which configures how many QoS 2 messages from the client can be processed by EMQX Broker simultaneously. 0 means no limit.

zone.external.await_rel_timeout

Description

Time for QoS 2 message processing timeout. If the QoS PUBREL message has not been received after the timeout, the message is dropped from the receiving window.

zone.external.session_expiry_interval

Description

The default timeout period of the session, which is mainly used for MQTT v3.1 and v3.1.1 protocols. In MQTT v5.0, this value is usually carried in the client’s connection message.

zone.external.max_mqueue_len

Description

The maximum length of the message queue. When the flight window is full, or the client is offline, the message will be stored in the queue. 0 means no limit.

zone.external.mqueue_priorities

Description

Queue message priority configuration:

• none：no prioritization.
• <Spec>：A message priority table, which configures the priority of messages under a certain topic. For example:
  • topic/1=10: indicates that the message priority of the topic topic/1 is 10.
  • topic/1=10,topic/2=8: indicates that the priority of two topics is configured, which are 10 and 8 respectively.
  • Among them, the higher the priority value, the higher the priority level.

When the length of the message queue is limited, low priority messages will be dropped first.

zone.external.mqueue_default_priority

Description

The default priority level of the message.

zone.external.mqueue_store_qos0

Description

Whether the message queue stores QoS 0 messages.

zone.external.enable_flapping_detect

Description

Whether to enable Flapping check.

zone.external.mountpoint

Description

After topic mount point is configured, all subscribed and published topics will be prefixed by EMQX Broker.

The available placeholders are:

• %c：Client ID.
• %u：Username.

For example, if the mount point is set to user/%c/. , when the client with client ID tom publishes the topic open message, the topic actually routed in EMQX Broker is user/tom/open.

zone.external.use_username_as_clientid

Description

Whether to use the client’s Username as its Client ID.

zone.external.ignore_loop_deliver

Description

Whether to ignore the message sent by yourself. If ignored, it means that EMQX Broker will not deliver this message to the sender of the message.

zone.external.strict_mode

Description

Whether to enable the strict check mode. The strict check mode will check the correctness of the MQTT message in more detail.

zone.internal.allow_anonymous

Description

Whether to allow anonymous users to log in to the system.

zone.internal.enable_stats

Description

Whether to enable client status statistics.

zone.internal.enable_acl

Description

Whether to enable ACL check.

zone.internal.acl_deny_action

Description

What to do after the ACL check fails.

• ignore：No operation.
• disconnect：Disconnect.

zone.internal.force_gc_policy

Description

When a certain number of messages, or bytes, are received, a garbage collection is forced.

Format: <Number> | <Bytes>.

For example, 16000|16MB means that when 16000 messages are received, or a byte of 16MB flows in, a garbage collection is forced.

zone.internal.wildcard_subscription

Description

Whether to support subscribing to wildcard topics.

zone.internal.shared_subscription

Description

Whether to support shared subscriptions.

zone.internal.max_subscriptions

Description

The maximum number of topics that a single client is allowed to subscribe to. 0 means no limit.

zone.internal.max_inflight

Description

Inflight window size: The flight window is used to store unanswered QoS 1 and QoS 2 messages.

zone.internal.max_awaiting_rel

Description

The maximum receiving window for QoS 2 messages, that configures how many QoS 2 messages from the client can be processed by EMQX Broker simultaneously. 0 means no limit.

zone.internal.max_mqueue_len

Description

The maximum length of the message queue. When the flight window is full, or the client is offline, the message will be stored in the queue. 0 means no limit.

zone.internal.mqueue_store_qos0

Description

Whether the message queue stores QoS 0 messages.

zone.internal.enable_flapping_detect

Description

Whether to enable Flapping check.

zone.internal.force_shutdown_policy

Description

When the process message queue length, or the memory bytes reaches a certain value, the process is forced to close.

The “message queue” here refers to the “message mailbox” of the Erlang process, not the “mqueue” of QoS 1 and QoS 2.

Format: <Number> | <Bytes>.

For example, 32000|32MB means that when the process accumulates 32000 messages, or the process occupies memory up to 32MB, the process is closed.

zone.internal.mountpoint

Description

After topic mount point is configured, all subscribed and published topics will be prefixed by EMQX Broker.

The available placeholders are:

• %c：Client ID.
• %u：Username.

For example, if the mount point is set to user/%c/. , when the client with client ID tom publishes the topic open message, the topic actually routed in EMQX Broker is user/tom/open.

zone.internal.ignore_loop_deliver

Description

Whether to ignore the message sent by itself. If ignored, it means that EMQX Broker will not deliver this message to the sender of the message.

zone.internal.strict_mode

Description

Whether to enable the strict check mode. The strict check mode will check the correctness of the MQTT message in more detail.

zone.internal.bypass_auth_plugins

Description

Whether to allow clients under this zone to bypass the authentication step of the authentication plugin.

listener.tcp.external

Description

Configure the listening address of the MQTT / TCP listener named external.

Example

1883: monitors IPv4 0.0.0.0: 1883. 127.0.0.1: 1883: monitor address is 1883 port on the 127.0.0.1 network card. :: 1: 1883: monitors the IPv6 address as 1883 port on the :: 1 network card.

listener.tcp.external.acceptors

Description

The size of the listener’s receiving pool.

listener.tcp.external.max_connections

Description

The maximum number of concurrent connections allowed by the listener.

listener.tcp.external.max_conn_rate

Description

The maximum access rate allowed by the listener. Unit: pcs / sec

listener.tcp.external.active_n

Description

The number of times the listener continues to receive TCP packets.

listener.tcp.external.zone

Description

The configuration zone to which the listener belongs.

listener.tcp.external.rate_limit

Description

The rate limit of the listener. The format is <limit>,<duration>.

Example

100KB,10s：Limit the number of incoming bytes within 10 seconds not to exceed 100 KB.

listener.tcp.external.access.1

Description

List of ACL rules of the listener. It is used to set the white/black list of the connection layer.

Example

allow all：Allow all TCP connections. allow 192.168.0.0/24：Allow TCP connection with network address 192.168.0.0/24.

At the same time, this configuration can configure multiple rules:

listener.tcp.external.access.1 = deny 192.168.0.1
listener.tcp.external.access.2 = allow all

It means that all TCP connections except 192.168.0.1 are allowed.

listener.tcp.external.proxy_protocol

Description

Whether the listener enables Proxy Protocol support.

If the EMQX cluster is deployed behind HAProxy or Nginx, and you need to get the client’s real source IP address and port, you need to enable this configuration.

Proxy Protcol : .

listener.tcp.external.proxy_protocol_timeout

Description

Set the timeout for Proxy Protocol parsing. If no Proxy Protocol packet is received within this time, EMQX Broker will close its connection.

listener.tcp.external.peer_cert_as_username

Description

Use the client certificate to override the value of the Username field. The optional values are:

• cn: the Common Name of the client certificate
• dn: the Subject Name of the client certificate
• crt: the DER-encoded binary of the client certificate
• pem: base64 encoded string based on the DER-encoded binary
• md5: MD5 hash of the DER-encoded binary

Note: Under TCP listener, this configuration is only available if the load balancing server terminates the SSL deployment; and the load balancing server needs to be configured to send the content of the certificate domain to EMQX. For example, for HAProxy, see send-proxy-v2-ssl (opens new window)

listener.tcp.external.peer_cert_as_clientid

Description

Use the client certificate to override the value of the ClientID field. The meaning of the optional values is the same as above.

listener.tcp.external.backlog

Description

The maximum length of the TCP connection queue. It indicates the maximum number of TCP connection queues that are allowed in the system to undergo three-time handshake.

listener.tcp.external.send_timeout

Description

Timeout for sending TCP packets.

listener.tcp.external.send_timeout_close

Description

Whether to close the connection after TCP packet sending timeout.

listener.tcp.external.recbuf

Description

TCP receiving buffer size (operating system kernel parameter)

Reference:

listener.tcp.external.sndbuf

Description

TCP sending buffer size (operating system kernel parameter).

Reference:http://erlang.org/doc/man/inet.html (opens new window).

listener.tcp.external.buffer

Description

TCP buffer size (user level).

This value is recommended to be greater than or equal to the maximum value of sndbuff and recbuff to avoid some performance problems. Without configuration, it equals to the maximum value of sndbuff and recbuff by default.

Reference: .

listener.tcp.external.tune_buffer

Description

If this configuration is enabled, please set the value equal to the maximum value of sndbuff and recbuff.

listener.tcp.external.nodelay

Description

This is the TCP_NODELAY parameter. Enabling this option allows small TCP data packets to be sent immediately.

listener.tcp.external.reuseaddr

Description

This is the SO_REUSEADDR parameter. Enabling this option allows the local port to be reused without waiting for the end of the TIME_WAIT state.

listener.tcp.internal

Description

Configure the listening address of the MQTT / TCP listener named internal.

Example

11883: listen to 0.0.0.0: 11883 of IPv4. 127.0.0.1:11883: listening address is11883 port on the network card. :: 1: 11883: listen to the 11883 port on the :: 1 network card of IPv6 address.

listener.tcp.internal.acceptors

Description

The size of the listener’s receiving pool.

listener.tcp.internal.max_connections

Description

The maximum number of concurrent connections allowed by the listener.

listener.tcp.internal.max_conn_rate

Description

The maximum access rate allowed by the listener. Unit: pcs / sec

listener.tcp.internal.active_n

Description

The number of times the listener continues to receive TCP packets.

listener.tcp.internal.zone

Description

The configuration zone to which the listener belongs.

listener.tcp.internal.rate_limit

Description

The rate limit of the listener. The format is <limit>,<duration>.

Example

100KB,10s：Limit the number of incoming bytes within 10 seconds no tot exceed 100 KB.

listener.tcp.internal.backlog

Description

The maximum length of the TCP connection queue. It indicates the maximum number of TCP connection queues that are allowed in the system to undergo three-time handshake.

listener.tcp.internal.send_timeout

Description

Timeout for sending TCP packets.

listener.tcp.internal.send_timeout_close

Description

Whether to close the connection after TCP packet sending timeout.

listener.tcp.internal.recbuf

Description

TCP receiving buffer size (operating system kernel parameter)

listener.tcp.internal.sndbuf

Description

listener.tcp.internal.buffer

Description

TCP buffer size (user level).

listener.tcp.internal.tune_buffer

Description

If this configuration is enabled, please set the value equal to the maximum value of sndbuff and recbuff.

listener.tcp.internal.nodelay

Description

This is the TCP_NODELAY parameter. Enabling this option allows small TCP data packets to be sent immediately.

listener.tcp.internal.reuseaddr

Description

This is the SO_REUSEADDR parameter. Enabling this option allows the local port to be reused without waiting for the end of the TIME_WAIT state.

listener.ssl.external

Description

Configure an SSL listener named external.

listener.ssl.external.acceptors

Description

The size of the listener’s receiving pool.

listener.ssl.external.max_connections

Description

The maximum number of concurrent connections allowed by the listener.

listener.ssl.external.max_conn_rate

Description

The maximum access rate allowed by the listener. Unit: pcs / sec.

listener.ssl.external.active_n

Description

The number of times the listener continues to receive TCP packets.

listener.ssl.external.zone

Description

The configuration group to which the listener belongs.

listener.ssl.external.access.1

Description

List of ACL rules of the listener. It is used to set the white/black list of the connection layer.

For example:

allow all：Allow all TCP connections. allow 192.168.0.0/24：Allow TCP connection with network address 192.168.0.0/24 to access.

At the same time, the configuration can configure multiple rules:

listener.ssl.external.access.1 = deny 192.168.0.1
listener.ssl.external.access.2 = allow all

listener.ssl.external.rate_limit

Description

Listener rate limit, with the format of <limit>,<duration>.

listener.ssl.external.proxy_protocol

Description

Whether the listener enables Proxy Protocol support.

If the EMQX cluster is deployed behind HAProxy or Nginx, and it is required to get the client’s real source IP address and port, you need to enable this configuration.

Proxy Protcol reference: https://www.haproxy.com/blog/haproxy/proxy-protocol (opens new window).

listener.ssl.external.proxy_protocol_timeout

Description

Set the timeout for Proxy Protocol parsing. If no Proxy Protocol packet is received within this time, EMQX Broker will close its connection.

listener.ssl.external.tls_versions

Description

Specify the SSL version list supported by the server. For details, see .

listener.ssl.external.handshake_timeout

Description

Specify the timeout period for the SSL handshake process.

listener.ssl.external.depth

Description

Maximum number of non-self-issued intermediate certificates that can follow the peer certificate in a valid certification path.

listener.ssl.external.key_password

Description

String containing the user’s password. Only used if the private keyfile is password-protected.

listener.ssl.external.keyfile

Description

File path to the server’s private key.

listener.ssl.external.certfile

Description

File path to the server’s certificate.

listener.ssl.external.cacertfile

Description

File path to the CA certificates. It should include all intermediate CA certificates and root CA certificate of the server certificate. It should also include trusted CAs to validate client certificates when verify configuration is set to verify_peer.

listener.ssl.external.enable_ocsp_stapling

Description

Introduced in e4.4.11.

Whether to enable OCSP stapling for the listener. If set to true, requires definining the OCSP responder URL. Such responses will be cached and sent to the connecting clients as part of the TLS handshake. This is only supported for TLS 1.2 and TLS 1.3.

Description

Introduced in e4.4.11.

URL for the OCSP responder to check the server certificate against when OCSP stapling is enabled. This response is cached and refresh periodically.

listener.ssl.external.ocsp_issuer_pem

Description

Introduced in e4.4.11.

Path to the file containing PEM-encoded certificate of the OCSP Stapling issuer. This certificate is used to validate that the stapling sent by a trusted server.

listener.ssl.external.ocsp_refresh_interval

Description

Introduced in e4.4.11.

The period to refresh the OCSP response for the server. Even if the response fails to be fetched during a refresh, the previously cached response will still be used until a newer response is successfully retrieved from the OCSP responder. Cannot be shorter than 1 minute.

listener.ssl.external.ocsp_refresh_http_timeout

Description

Introduced in e4.4.11.

The timeout for the HTTP request when fetching OCSP responses from the OCSP responder.

listener.ssl.external.enable_crl_check

Description

Introduced in e4.4.11.

Whether to enable CRL verification and caching for this listener.

Note: In the event of cache miss, EMQX will attempt to fetch the CRL on the fly from the URL declared in the client certificate’s distribution point(s). If no corresponding CRL is cached or fetched successfully and CRL check is enabled, then the client will be denied connection.

listener.ssl.external.crl_cache_urls

Description

Introduced in e4.4.11.

Comma-separated URL list for CRL servers to fetch and cache CRLs from. Must include the path to the CRL file(s) in the paths (e.g.: http://my.crl.server/intermediate.crl.pem, http://my.other.crl.server/another.crl.pem).

crl_cache_http_timeout

Description

Introduced in e4.4.11.

The timeout for the HTTP request when fetching CRLs. This is global for all listeners.

crl_cache_refresh_interval

Description

Introduced in e4.4.11.

The period to refresh the CRLs from the servers. This is global for all URLs and listeners. Cannot be shorter than 1 minute.

listener.ssl.external.dhfile

Description

If using the Ephemeral Diffie-Hellman algorithm, specify the key file used by the algorithm.

listener.ssl.external.verify

Description

Specifies whether to verify the client during the handshake.

listener.ssl.external.fail_if_no_peer_cert

Description

If the client does not have a certificate during the SSL handshake, it determines whether to let the handshake fail.

listener.ssl.external.ciphers

Description

Specify the cipher suite supported by the server.

listener.ssl.external.psk_ciphers

Description

If using the PSK algorithm, specify the PSK Cipher list supported by the server. Note that only one of ‘listener.ssl.external.ciphers’ and ‘listener.ssl.external.psk_ciphers’ can be configured.

listener.ssl.external.secure_renegotiate

Description

Specifies whether to reject renegotiation requests if the client does not follow RFC 5746

listener.ssl.external.reuse_sessions

Description

Specify whether to support SSL session reuse. For details, seehttp://erlang.org/doc/man/ssl.html (opens new window).

listener.ssl.external.honor_cipher_order

Description

Specify whether to use the server’s preferences to select Ciphers.

listener.ssl.external.peer_cert_as_username

Description

Use the client certificate to override the value of the Username field. The optional values are:

• cn: the Common Name of the client certificate
• dn: the Subject Name of the client certificate
• crt: the DER-encoded binary of the client certificate
• pem: base64 encoded string based on the DER-encoded binary
• md5: MD5 hash of the DER-encoded binary

Note that listener.ssl.external.verify should be set to verify_peer.

listener.tcp.external.peer_cert_as_clientid

Description

Use the client certificate to override the value of the ClientID field. The meaning of the optional values is the same as above.

listener.ssl.external.backlog

Description

The maximum length of the TCP connection queue. It indicates the maximum number of TCP connection queues that are allowed in the system to undergo three-time handshake.

listener.ssl.external.send_timeout

Description

Timeout for sending TCP packets.

listener.ssl.external.send_timeout_close

Description

Whether to close the connection after TCP packet sending timeout.

listener.ssl.external.recbuf

Description

TCP receiving buffer size (operating system kernel level parameter).

Reference:.

listener.ssl.external.sndbuf

Description

TCP sending buffer size (operating system kernel level parameter).

Reference:http://erlang.org/doc/man/inet.html (opens new window).

listener.ssl.external.buffer

Description

CP buffer size (user level).

This value is recommended to be greater than or equal to the maximum value of sndbuff and recbuff to avoid some performance problems. Without configuration, it equals to the maximum value of sndbuff and recbuff by default.

Reference:.

listener.ssl.external.tune_buffer

Description

If this configuration is enabled, please set the value equal to the maximum value of sndbuff and recbuff.

listener.ssl.external.nodelay

Description

This is the TCP_NODELAY parameter. Enabling this option means that the Nagle algorithm is disabled and small packets will be sent immediately.

listener.ssl.external.reuseaddr

Description

This is the SO_REUSEADDR parameter. Enabling this option allows the local port to be reused without waiting for the end of the TIME_WAIT state.

listener.ws.external

Description

Configure the listening address of the MQTT/WS listener named external.

Example

8083: Listen s to 0.0.0.0: 8083 of IPv4. 127.0.0.1:8083: Listening address is 8083 port on the 127.0.0.1 network card. :: 1: 8083: Listen to the 8083 port on the network card :: 1 of IPv6 address.

listener.ws.external.mqtt_path

Description

WebSocket’s MQTT protocol path. So the address of EMQX Broker’s WebSocket is: ws://{ip}:{port}/mqtt.

listener.ws.external.acceptors

Description

The size of the listener’s receiving pool.

listener.ws.external.max_connections

Description

The maximum number of concurrent connections allowed by the listener.

listener.ws.external.max_conn_rate

Description

The maximum access rate allowed by the listener. Unit: pcs/sec

listener.ws.external.active_n

Description

The number of times the listener continues to receive TCP packets.

listener.ws.external.rate_limit

Description

The rate limit of the listener. The format is <limit>,<duration>.

Example

100KB,10s： Limit the number of incoming bytes within 10 seconds to not exceed 100 KB.

listener.ws.external.zone

Description

The configuration zone to which the listener belongs.

listener.ws.external.access.1

Description

List of ACL rules of the listener. It is used to set the white/black list of the connection layer.

listener.ws.external.verify_protocol_header

Description

Whether to verify that the HTTP header carried by WebSocket is correct. WeChat applet needs to disable this verification.

listener.ws.external.fail_if_no_subprotocol

Description

If set to true, the server will return an error when the client does not carry the Sec-WebSocket-Protocol field. WeChat applet needs to disable this verification.

listener.ws.external.supported_subprotocols

Description

Specify the supported subprotocols, separated by commas.

listener.ws.external.proxy_address_header

Description

If the EMQX cluster is deployed behind HAProxy or Nginx, you can open the configuration to obtain the real IP address of the client.

listener.ws.external.proxy_port_header

Description

If the EMQX cluster is deployed behind HAProxy or Nginx, you can open the configuration to get the real port of the client.

listener.ws.external.proxy_protocol

Description

Whether the listener enables Proxy Protocol support.

If the EMQX cluster is deployed behind HAProxy or Nginx, and you need to get the client’s real source IP address and port, you need to open this configuration.

Proxy Protcol reference: https://www.haproxy.com/blog/haproxy/proxy-protocol (opens new window).

listener.ws.external.proxy_protocol_timeout

Description

Set the timeout for Proxy Protocol parsing. If no Proxy Protocol packet is received within this time, EMQX Broker will close its connection.

listener.ws.external.backlog

Description

The maximum length of the TCP connection queue. It indicates the maximum number of TCP connection queues that are allowed in the system to undergo three-time handshake.

listener.ws.external.send_timeout

Description

Timeout for sending TCP packets.

listener.ws.external.send_timeout_close

Description

Whether to close the connection after TCP packet sending timeout.

listener.ws.external.recbuf

Description

TCP receiving buffer size (operating system kernel level parameter)

listener.ws.external.sndbuf

Description

TCP sending buffer size (operating system kernel level parameter)

listener.ws.external.buffer

Description

TCP buffer size (user level).

listener.ws.external.tune_buffer

Description

If this configuration is enabled, please set the value equal to the maximum value of sndbuff and recbuff.

listener.ws.external.nodelay

Description

This is the TCP_NODELAY parameter. Enabling this option allows small TCP data packets to be sent immediately.

listener.ws.external.compress

Description

Whether to compress WebSocket messages. The implementation of compression depends on .

The configuration items under defalte_opts belong to the compression-related parameter configuration, if not necessary, please do not modify it.

listener.ws.external.deflate_opts.level

Description

compression level

listener.ws.external.deflate_opts.mem_level

Description

Compression parameters. It means memory usage limit level, and configure how much memory can be opened to participate in the compression process.

1: The least memory, but will reduce the compression rate. 9: The most memory, and will increase the calculation speed and compression rate.

If not configured, the default is 8.

listener.ws.external.deflate_opts.strategy

Description

Compression strategy for tuning compression ratio:

• default: for ordinary data.
• filtered: data generated by filters or predictors, suitable for content with strong randomness.
• huffman_only: Mandatory use of Huffman algorithm. Better than filtered.
• rle: limit the matching distance to 1 (Run-Lenght Encoding), faster than huffman_only, but mainly used for PNG images.

These strategies only affect the compression ratio and will not have any impact on correctness.

listener.ws.external.deflate_opts.server_context_takeover

Description

Whether to allow the server’s compression context to be passed between frames.

listener.ws.external.deflate_opts.client_context_takeover

Description

Whether to allow the client’s compression context to be passed between frames.

listener.ws.external.deflate_opts.server_max_window_bits

Description

Maximum window value on the server side. Setting a larger value will result in better compression ratio, but will consume additional memory.

listener.ws.external.deflate_opts.client_max_window_bits

Description

Client maximum window value. Setting a larger value will result in better compression ratio, but will consume additional memory.

listener.ws.external.idle_timeout

Description

The daze time after the TCP connection is established. If no packets are received within this time, the connection will be closed.

listener.ws.external.max_frame_size

Description

The maximum allowed length of a single MQTT packet.

listener.wss.external

Description

Configure a WSS (MQTT/WebSocket/SSL) listener named external.

listener.wss.external.mqtt_path

Description

WebSocket URL Path.

listener.wss.external.acceptors

Description

The size of the listener’s receiving pool.

listener.wss.external.max_connections

Description

The maximum number of concurrent connections allowed by the listener.

listener.wss.external.max_conn_rate

Description

The maximum access rate allowed by the listener. Unit: pcs/sec.

listener.wss.external.active_n

Description

The number of times the listener continues to receive TCP packets.

listener.wss.external.rate_limit

Description

The rate limit of the listener. The format is <limit>,<duration>.

listener.wss.external.zone

Description

The configuration group to which the listener belongs.

listener.wss.external.access.1

Description

List of ACL rules of the listener. It is used to set the white/black list of the connection layer.

E.g:

allow all: Allow all TCP connections. allow 192.168.0.0/24: Allow TCP connections with a network address of 192.168.0.0 / 24 to access.

At the same time, the configuration can configure multiple rules:

listener.wss.external.access.1 = deny 192.168.0.1
listener.wss.external.access.2 = allow all

listener.wss.external.fail_if_no_subprotocol

Description

If set to true, the server will return an error when the client does not carry the Sec-WebSocket-Protocol field. WeChat applet needs to disable this verification.

listener.wss.external.supported_subprotocols

Description

Specify the supported subprotocols, separated by commas.

listener.wss.external.proxy_address_header

Description

If the EMQX cluster is deployed in HAProxy or Nginx, you can open the configuration to obtain the real IP address of the client.

listener.wss.external.proxy_protocol

Description

Whether the listener enables Proxy Protocol support.

If the EMQX cluster is deployed behind HAProxy or Nginx, and you need to get the client’s real source IP address and port, you need to open this configuration.

Proxy Protcol reference:https://www.haproxy.com/blog/haproxy/proxy-protocol (opens new window).

listener.wss.external.proxy_protocol_timeout

Description

Set the timeout for Proxy Protocol parsing. If no Proxy Protocol packet is received within this time, EMQX Broker will close its connection.

listener.wss.external.peer_cert_as_username

Description

Use the client certificate to override the value of the Username field. The optional values are:

• cn: the Common Name of the client certificate
• dn: the Subject Name of the client certificate
• crt: the DER-encoded binary of the client certificate
• pem: base64 encoded string based on the DER-encoded binary
• md5: MD5 hash of the DER-encoded binary

Note that listener.wss.external.verify should be set to verify_peer.

listener.wss.external.peer_cert_as_clientid

Description

Use the client certificate to override the value of the ClientID field. The meaning of the optional values is the same as above.

listener.wss.external.tls_versions

Description

Specify the SSL version list supported by the server. For details, see .

listener.wss.external.keyfile

Description

File path to server’s private key.

listener.wss.external.certfile

Description

File path to the server’s certificate.

listener.wss.external.cacertfile

Description

File path to the CA certificates. It should include all intermediate CA certificates and root CA certificate of the server certificate. It should also include trusted CAs to validate client certificates when verify configuration is set to verify_peer.

listener.wss.external.depth

Description

Maximum number of non-self-issued intermediate certificates that can follow the peer certificate in a valid certification path.

listener.wss.external.key_password

Description

String containing the user’s password. Only used if the private keyfile is password-protected.

listener.wss.external.dhfile

Description

If using the Ephemeral Diffie-Hellman algorithm, specify the key file used by the algorithm.

listener.wss.external.verify

Description

Specifies whether to verify the client during the handshake.

listener.wss.external.fail_if_no_peer_cert

Description

If the client does not have a certificate during the SSL handshake, it determines whether to let the handshake fail.

listener.wss.external.ciphers

Description

Specifies the cipher suite supported by the server.

listener.wss.external.psk_ciphers

Description

If using the PSK algorithm, specify the PSK Cipher list supported by the server. Note that only one of ‘listener.wss.external.ciphers’ and ‘listener.wss.external.psk_ciphers’ can be configured.

listener.wss.external.secure_renegotiate

Description

Specifies whether to reject renegotiation requests if the client does not follow RFC 5746

listener.wss.external.reuse_sessions

Description

Specifies whether to support SSL session reuse. For details, see http://erlang.org/doc/man/ssl.html (opens new window).

listener.wss.external.honor_cipher_order

Description

Specify whether to use the server’s preferences to select Ciphers.

listener.wss.external.peer_cert_as_username

Description

Use the value of the CN, DN, or CRT field in the client certificate as the value of the Username field in the MQTT CONNECT packet. Note that listener.wss.external.verify should be set to verify_peer.

listener.wss.external.backlog

Description

The maximum length of the TCP connection queue. It indicates the maximum number of TCP connection queues that are allowed in the system to undergo three-time handshake.

listener.wss.external.send_timeout

Description

Timeout for sending TCP packets.

listener.wss.external.send_timeout_close

Description

Whether to close the connection after TCP packet sending timeout.

listener.wss.external.recbuf

Description

TCP receiving buffer size (operating system kernel level parameter)

Reference:

listener.wss.external.sndbuf

Description

TCP sending buffer size (operating system kernel level parameter)

Reference:http://erlang.org/doc/man/inet.html

listener.wss.external.buffer

Description

TCP buffer size (user level).

This value is recommended to be greater than or equal to the maximum value of sndbuff and recbuff to avoid some performance problems. Without configuration, it equals to the maximum value of sndbuff and recbuff by default.

Reference:

listener.wss.external.tune_buffer

Description

If you open this configuration, please set the value equal to the maximum value of sndbuff and recbuff.

listener.wss.external.nodelay

Description

This is the TCP_NODELAY parameter. Enabling this option allows small TCP data packets to be sent immediately.

listener.wss.external.compress

Description

If this option is set to true, Websocket messages will be compressed.

listener.wss.external.deflate_opts.level

Description

Compression level.

listener.wss.external.deflate_opts.mem_level

Description

Compression parameters. It means memory usage limit level, configures how much memory can be opened to participate in the compression process.

1: The least memory, but will reduce the compression rate. 9: The most memory, and will increase the calculation speed and compression rate.

If not configured, the default is 8.

listener.wss.external.deflate_opts.strategy

Description

Compression strategy for tuning compression ratio:

• default: for ordinary data.
• filtered: data generated by filters or predictors, suitable for content with strong randomness.
• huffman_only: Mandatory use of Huffman algorithm. Better than filtered.
• rle: limit the matching distance to 1 (Run-Lenght Encoding), faster than huffman_only, but mainly used for PNG images.

These strategies only affect the compression ratio and will not have any impact on correctness.

listener.wss.external.deflate_opts.server_context_takeover

Description

Whether to allow the server’s compression context to be passed between frames.

listener.wss.external.deflate_opts.client_context_takeover

Description

Whether to allow the client’s compression context to be passed between frames.

listener.wss.external.deflate_opts.server_max_window_bits

Description

Maximum window value on the server side. Setting a larger value will result in better compression ratio, but will consume additional memory.

listener.wss.external.deflate_opts.client_max_window_bits

Description

Client maximum window value. Setting a larger value will result in better compression ratio, but will consume additional memory.

listener.wss.external.idle_timeout

Description

The daze time after the TCP connection is established. If no packets are received within this time, the connection will be closed.

listener.wss.external.max_frame_size

Description

The maximum length of a single MQTT packet.

plugins.etc_dir

Description

The configuration directory of the plugin.

plugins.loaded_file

Description

The configuration file path of the plugin startup list.

plugins.expand_plugins_dir

Description

External plugin storage directory.

broker.sys_interval

Description

Set the system topic ($SYS) message release interval.

broker.sys_heartbeat

Description

Set the system heartbeat message release interval. The system heartbeat message includes the following two topics:

• “$SYS/brokers/<node>/uptime”
• “$SYS/brokers/<node>/datetime”

broker.enable_session_registry

Description

Enable or disable global session registration.

broker.session_locking_strategy

Description

Set the type of session cluster lock. The session cluster lock is used to prevent the same client from creating multiple sessions on multiple different nodes, which is common when clients frequently switch between nodes for logging.

broker.shared_subscription_strategy

Description

Set a dispatch strategy for shared subscribers. Options are:

• hash_clientid: Map (hash) publisher ClientID to subscriber.
• hash_topic: Map (hash) source MQTT topic to subscriber.
• local: Select a random subscriber in the group locally in the node which is processing the shared-publish request. If there is no such local subscriber, it fallbacks to random strategy
• random: Choose randomly among all subscribers.
• round_robin: Enumerate subscribers in (unsorted) order.
• sticky: First dispatch is random, then stick to it for all subsequent messages until that subscriber goes disconnected or that publisher reconnects.

broker.sample_group.shared_subscription_strategy

Overrides the dispatch strategy for a shared subscription group named sample_group. If not configured, broker.shared_subscription_strategy is used,

Where sample_group can be configured to any group name.

The available strategies are the same as broker.shared_subscription_strategy.

broker.shared_dispatch_ack_enabled

Description

Enable or disable the ACK check function for qos1/qos2 messages in shared subscriptions. After enabling, if it is delivered to a subscriber but fails to receive the ACK, it will try to deliver to the next subscriber in the subscription group.

broker.route_batch_clean

Description

Enable or disable batch cleanup routing information. Batch cleanup routing can be used in a short period of time when a large number of clients go offline to improve cleanup efficiency.

broker.perf.route_lock_type = key

Description

Choose the granularity of the database lock when updating the routing information for whildcard subscriptions.

• key (default) is to take a lock for each key representing prefixes of a wildcard topic;
• tab is to take the lock for the entire table which stores prefixes of wildcard topics;
• global is to take a global lock.

Options tab and global are recommended for large scale clusters (e.g. more than 7 nodes) especially when network latency between the nodes is at milliseconds level. NOTE: It requires entire cluster to be stopped before changing this config.

broker.perf.trie_compaction

Description

Set to true to compact the routing information table for wildcard topics. Compaction is optimized for writes, handles high rate subscription requests quicker, it also requires half of the RAM comparing to non-compacted. Non-compaction is optimized for reads (e.g. large number of topic levels in publish requests).

NOTE: Changing from false to true can be done by rolling-restart the nodes in a cluster. The safe way of changing from true to false is to stop all nodes in the cluster, otherwise some message may not get routed before all nodes have restarted.

sysmon.long_gc

Description

Enable garbage collection time monitoring and trigger an alarm when the collection time exceeds the set value, 0 means disabling this monitoring.

monitor

sysmon.long_schedule

Description

Enable process scheduling time monitoring and trigger an alarm when the scheduling time exceeds the set value, 0 means disabling this monitoring.

sysmon.large_heap

Description

Enable stack size monitoring and trigger an alarm when the stack size is still greater than the set value after the process performs garbage collection. 0 means disabling this monitoring.

sysmon.busy_port

Description

Specifies whether to enable inter-process message channel busy monitoring.

sysmon.busy_dist_port

Description

Specifies whether to enable cluster RPC channel busy monitoring.

os_mon.cpu_check_interval

Description

CPU usage rate check cycle.

os_mon.cpu_high_watermark

Description

An alarm will be triggered when the CPU usage exceeds os_mon.cpu_high_watermark.

os_mon.cpu_low_watermark

Description

The alarm will be cleared when the CPU usage drops back below os_mon.cpu_low_watermark .

os_mon.mem_check_interval

Description

Memory usage check cycle.

os_mon.sysmem_high_watermark

Description

When the memory allocated by EMQX Broker for all processes as a percentage of system memory exceeds os_mon.procmem_high_watermark, an alarm will be triggered.

os_mon.procmem_high_watermark

Description

When the memory allocated by EMQX Broker for a single process as a percentage of system memory exceeds os_mon.procmem_high_watermark, an alarm will be triggered.

vm_mon.check_interval

Description

Check interval for process number.

vm_mon.process_high_watermark

Description

When the current process number as a percentage of the maximum process number exceeds vm_mon.process_high_watermark, an alarm will be triggered. The maximum process number is determined by the node.process_limit configuration item.

vm_mon.process_low_watermark

Description

When the percentage of the current number of processes in the maximum number of processes falls below vm_mon.process_low_watermark, an alarm will be triggered. The maximum number of processes is determined by the node.process_limit configuration item.

Plugin emqx_auth_http

auth.http.auth_req.url

Description

Specify the target URL of the authentication request.

auth.http.auth_req.method

Description

Specify the request method of the authentication request.

auth.http.auth_req.headers.<Any>

Example

auth.http.auth_req.headers.content-type = application/x-www-form-urlencoded
auth.http.auth_req.headers.accept = */*

Description

Specify the data in the HTTP request header. <Key> Specify the field name in the HTTP request header, and the value of this configuration item is the corresponding field value. <Key> can be the standard HTTP request header field. User can also customize the field to configure multiple different request header fields.

auth.http.auth_req.params

Description

Specify the data carried in the authentication request. When using the GET method, the value of auth.http.auth_req.params will be converted into k=v key-value pairs separated by & and sent as query string parameters. When using the POST method, the value of auth.http.auth_req.params will be converted into k=v key-value pairs separated by & and sent in the form of Request Body. All placeholders will be replaced by run-time data , and the available placeholders are as follows:

auth.http.super_req.url

Description

Specify the target URL for the superuser authentication request.

auth.http.super_req.method

Description

Specifies the request method of the super user authentication request.

auth.http.super_req.headers.<Any>

Example

auth.http.super_req.headers.content-type = application/x-www-form-urlencoded
auth.http.super_req.headers.accept = */*

Description

Specify the data in the HTTP request header. <Key> Specify the field name in the HTTP request header, and the value of this configuration item is the corresponding field value. <Key> can be the standard HTTP request header field. User can also customize the field to configure multiple different request header fields.

auth.http.super_req.params

Description

Specify the data carried in the authentication request. When using the GET method, the value of auth.http.auth_req.params will be converted into k=v key-value pairs separated by & and sent as query string parameters. When using the POST method, the value of auth.http.auth_req.params will be converted into k=v key-value pairs separated by & and sent in the form of Request Body. All placeholders will be replaced by run-time data , and the available placeholders are the same as those of auth.http.auth_req.params.

auth.http.acl_req.url

Description

Specify the target URL for ACL verification requests.

auth.http.acl_req.method

Description

Specifies the request method for ACL verification requests.

auth.http.acl_req.headers.<Any>

Example

auth.http.acl_req.headers.content-type = application/x-www-form-urlencoded
auth.http.acl_req.headers.accept = */*

Description

Specify the data in the HTTP request header. <Key> Specify the field name in the HTTP request header, and the value of this configuration item is the corresponding field value. <Key> can be the standard HTTP request header field. User can also customize the field to configure multiple different request header fields.

auth.http.acl_req.params

Description

Specify the data carried in the authentication request. When using the GET method, the value of auth.http.auth_req.params will be converted into k=v key-value pairs separated by & and sent as query string parameters. When using the POST method, the value of auth.http.auth_req.params will be converted into k=v key-value pairs separated by & and sent in the form of Request Body. All placeholders will be replaced by run-time data , and the available placeholders are as follows:

auth.http.timeout

Description

HTTP request timeout. Any setting equivalent to 0s means never timeout.

auth.http.connect_timeout

Description

Connection timeout for HTTP requests. Any setting value equivalent to 0s means never time out.

auth.http.pool_size

Description

HTTP client connection process pool size.

auth.http.ssl.cacertfile

Description

CA certificate file path.

auth.http.ssl.certfile

Description

Client certificate file path.

auth.http.ssl.keyfile

Description

Client private key file path.

Plugin emqx_auth_jwt

auth.jwt.secret

Description

Set HMAC Secret.

auth.jwt.from

Description

Where to get JWT. Optional values are

• username: The username field of the MQTT CONNECT packet is used as JWT.
• password: The password field of the MQTT CONNECT packet is used as JWT.

auth.jwt.pubkey

Description

If you use RSA or ECDSA encryption algorithm, you must specify the private key file.

auth.jwt.verify_claims

Description

Enable or disable Claims verification.

auth.jwt.verify_claims.<claims>

Description

When the Claims verification function is enabled, you can set optional values for fields in the JWT.

For example, if the value of sub in the Claim in JWT is expected to be” abc “, the following rules can be configured:

auth.jwt.verify_claims.sub = abc

The expected value supports two wildcards:

• %u: username
• %c: clientid

For example, if the value of the sub field in the JWT is expected to be the same as the username field in the MQTT CONNECT message, the following rules can be configured:

auth.jwt.verify_claims.sub = %u

auth.ldap.servers

Description

LDAP service address.

auth.ldap.port

Description

LDAP service port.

auth.ldap.pool

Description

Connection pool size.

auth.ldap.bind_dn

Description

The DN for logging into the LDAP service.

auth.ldap.bind_password

Description

The password for logging into the LDAP service.

auth.ldap.timeout

Description

The query timeout.

auth.ldap.device_dn

Description

The DN to which the client belongs.

auth.ldap.match_objectclass

Description

The name of the client object.

auth.ldap.username.attributetype

Description

The data type of the Username attribute.

auth.ldap.password.attributetype

Description

The data type of the Password attribute.

auth.ldap.ssl

Description

Whether to enable SSL.

auth.ldap.ssl.certfile

Description

SSL server certificate path.

auth.ldap.ssl.keyfile

Description

SSL server key file path.

auth.ldap.ssl.cacertfile

Description

CA certificate file path.

auth.ldap.ssl.verify

Description

SSL authentication method:

• verify_none：One-way authentication.
• verify_peer：Two-way authentication.

auth.ldap.ssl.fail_if_no_peer_cert

Description

If the client does not provide an SSL certificate, disconnect it.

Plugin emqx_auth_mongo

auth.mongo.type

Description

Set the topology type of MongoDB:

• single: single node
• unknown: unknown
• sharded: sharding mode
• rs: replicated set

auth.mongo.rs_set_name

Description

Set the address of MongoDB service. If there are multiple items, use comma , to separate them.

auth.mongo.pool

Description

Set the number of processes in the MongoDB connection pool.

auth.mongo.login

Description

Set the MongoDB’s username.

auth.mongo.password

Description

auth.mongo.auth_source

Description

Set the MongoDB authentication source database name.

auth.mongo.database

Description

Set MongoDB database name.

auth.mongo.query_timeout

Description

Set the timeout for accessing MongoDB.

auth.mongo.ssl

Description

Set whether to use SSL to access MongoDB.

auth.mongo.ssl_opts.keyfile

Description

If using SSL to access MongoDB, set the private key file of the SSL client.

auth.mongo.ssl_opts.certfile

Description

If using SSL to access MongoDB, set the SSL client certificate file.

auth.mongo.ssl_opts.cacertfile

Description

If you use SSL to access MongoDB, set the SSL certificate file.

auth.mongo.w_mode

Description

Set the write mode of MongoDB.

auth.mongo.r_mode

Description

Set the read mode of MongoDB.

auth.mongo.auth_query.collection

Description

Collection name used in the authentication process.

auth.mongo.auth_query.password_field

Description

The main fields used in the authentication process. To add salt after the password, it can be configured as:

auth.mongo.auth_query.password_hash

Description

Set the hash algorithm used for the password field. To add salt after the sha256 password, you can set it to:

auth.mongo.auth_query.password_hash = sha256,salt

To add salt before the sha256 password, you can set it to:

auth.mongo.auth_query.password_hash = salt,sha256

To add salt before the bcrypt password, you can set it to:

auth.mongo.auth_query.password_hash = salt,bcrypt

auth.mongo.auth_query.selector

Description

MongoDB statements are executed during the authentication process. Commands can support following wildcards:

• %u: username
• %c: clientid
• %C: Common Name in client TLS certificate
• %d: Subject in the client’s TLS certificate

auth.mongo.auth_query.super_query

Description

Whether to use SuperUser in authentication.

auth.mongo.super_query.collection

Description

If using SuperUser, specify the MongoDB Collection of SuperUser.

auth.mongo.super_query.selector

Description

If SuperUser is used, specify the MongoDB statement used to query SuperUser.

auth.mongo.acl_query

Description

Whether to enable the ACL function.

auth.mongo.acl_query.collection

Description

If using the ACL function, specify the MongoDB Collection that queries the ACL rules.

auth.mongo.acl_query.selector

Description

If the ACL function is used, specify the MongoDB statement used to query the ACL rules. It can support multiple ACL statements, and “or” is used to connect multiple statements.

For example, configure the following two access rules:

auth.mongo.acl_query.selector.1 = username=%u
auth.mongo.acl_query.selector.2 = username=$all

And the username of the client equals ‘ilyas’. When querying acl rules, the following MongoDB statement will be executed:

db.mqtt_acl.find({$or: [{username: "ilyas"},  {username: "$all"}]});

auth.mongo.topology.pool_size

Description

MongoDB topology parameters, that set the thread pool size.

auth.mongo.topology.max_overflow

Description

MongoDB topology parameter, which determines how many additional worker threads are allowed to be created when all workers in the thread pool are busy.

auth.mongo.topology.overflow_ttl

Description

MongoDB topology parameter, which determines how long to release additional worker threads when a worker is idle. Unit: ms

auth.mongo.topology.overflow_check_period

Description

MongoDB topology parameters, which determines how often to check for idle threads to release additional workers.

auth.mongo.topology.local_threshold_ms

Description

MongoDB topology parameters, which is to select the strategy of the secondary node used to process user requests. The minimum value of the RTT of all nodes is LowestRTT, then only those secondary nodes with RTT <LowestRTT + local_threshold_ms will be selected.

Description

MongoDB topology parameter, means MongoDB connection timeout, unit: ms.

auth.mongo.topology.socket_timeout_ms

Description

MongoDB topology parameter, that means MongoDB message sending timeout period, unit: ms.

auth.mongo.topology.server_selection_timeout_ms

Description

Specifies how long (in milliseconds) to block for server selection.

auth.mongo.topology.wait_queue_timeout_ms

Description

The maximum time in milliseconds for a worker to wait for a connection to become available.

auth.mongo.topology.heartbeat_frequency_ms

Description

MongoDB topology parameters, the interval between topological scans, unit: ms.

auth.mongo.topology.min_heartbeat_frequency_ms

Description

MongoDB topology parameter, the minimum allowed value of heartbeat_frequency_ms, unit: milliseconds.

Plugin emqx_auth_mysql

auth.mysql.server

Description

MySQL server address.

auth.mysql.pool

Description

Database connection thread pool size.

auth.mysql.username

Description

MySQL username.

auth.mysql.password

Description

MySQL password.

auth.mysql.database

Description

MySQL database name.

auth.mysql.query_timeout

Description

MySQL data query timeout. The query timeout means user data was not found.

auth.mysql.auth_query

Description

The MySQL select statement used during authentication, the selected data will be compared with the password encrypted by the encryption method specified by auth.mysql.password_hash, and the client with the same content after the comparison will be allowed to log in. The stored password with salt needs to select the fields corresponding to the salt at the same time, such as select password, salt from mqtt_user where username = '%u' limit 1.Password and salt field names cannot be modified, the table name and the field name in the WHERE clause can change depending on the situation. The WHERE clause supports the following placeholders:

auth.mysql.password_hash

Description

The encryption method used for the password stored in the database. The following encryption methods are supported:

• plain, both forward and backward salting is supported, such as salt, plain
• md5, both forward and backward salting is supported
• sha, both forward and backward salting is supported
• sha256, both forward and backward salting is supported
• sha512, both forward and backward salting is supported
• pbkdf2, the format is pbkdf2,<Hashfun>,<Iterations>,<Dklen>. Among them, <Hashfun>is the hash function used, which supports md4, md5,ripemd160 sha,sha224, sha256,sha384, sha512. <Iterations>is the number of iterations and <Dklen>is the length of the derived key. Example: pbkdf2, sha256,1000,20
• bcrypt, only forward salting is supported, eg salt, bcrypt

auth.mysql.super_query

Description

The SQL select statement used for super user authentication. All table names and field names in this statement can be modified as appropriate. If and only if the value of the selected field is 1, the user is a super user. In the WHERE clause, the supported placeholders are the same as auth.mysql.auth_query.

auth.mysql.acl_query

Description

The SQL selection statement used in ACL verification. All table names and field names in this statement can be modified as appropriate. The placeholders supported in the WHERE clause are as follows:

Plugin emqx_auth_pgsql

auth.pgsql.server

Description

PostgreSQL server address.

auth.pgsql.pool

Description

Database connection thread pool size.

auth.pgsql.username

Description

PostgreSQL username.

auth.pgsql.password

Description

PostgreSQL password.

auth.pgsql.database

Description

PostgreSQL database name.

auth.pgsql.encoding

Description

PostgreSQL database character encoding format.

auth.pgsql.ssl

Description

Whether to enable TLS connection.

auth.pgsql.ssl_opts.keyfile

Description

Client private key file path.

auth.pgsql.ssl_opts.certfile

Description

Client certificate file path.

auth.pgsql.ssl_opts.cacertfile

Description

Client CA certificate file path.

auth.pgsql.auth_query

Description

The SQL selection statement used for authentication, that is the same as auth.mysql.auth_query.

auth.pgsql.password_hash

Description

The encryption method used for the password stored in the database, that is the same as auth.mysql.password_hash.

auth.pgsql.super_query

Description

The SQL select statement used for super user authentication, that is the same as auth.mysql.super_query.

auth.pgsql.acl_query

Description

The SQL selection statement used in ACL verification, the same as auth.mysql.acl_query.

Plugin emqx_auth_redis

auth.redis.type

Description

Redis Service cluster type:

• single：Single node service.
• sentinel：sentinel pattern.
• cluster：cluster pattern.

auth.redis.server