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This section describes how to start a Cluster by manually starting all the needed processes.
Before continuing, be sure to read the Architecture section to get a basic understanding of the underlying architecture and the involved roles in an ArangoDB Cluster.
We will include commands for a local test (all processes running on a single machine) and for a more real production scenario, which makes use of 3 different machines.
In this paragraph we will include commands to manually start a Cluster with 3 Agents, 2 DB-Servers and 2 Coordinators.
We will assume that all processes runs on the same machine (127.0.0.1). Such scenario should be used for testing only.
To start up an Agency you first have to activate it. This is done by providing the option .
To start up the Agency in its fault tolerant mode set the --agency.size to 3. You will then have to start at least 3 Agents before the Agency will start operation.
During initialization the Agents have to find each other. To do so provide at least one common --agency.endpoint. The Agents will then coordinate startup themselves. They will announce themselves with their external address which may be specified using --agency.my-address. This is required in bridged docker setups or NATed environments.
So in summary these are the commands to start an Agency of size 3:
Local Test DB-Servers and Coordinators
These two roles share a common set of relevant options. First you should specify the role using --cluster.my-role. This can either be PRIMARY (a DB-Server) or COORDINATOR. Note that starting from v.3.4 DBSERVER is allowed as an alias for PRIMARY as well. Furthermore please provide the external endpoint (IP and port) of the process via --cluster.my-address.
The following is a full example of what it might look like.
DB-Servers:
arangod --server.authentication=false \--server.endpoint tcp://0.0.0.0:6001 \--cluster.my-address tcp://127.0.0.1:6001 \--cluster.my-role DBSERVER \--cluster.agency-endpoint tcp://127.0.0.1:5001 \--cluster.agency-endpoint tcp://127.0.0.1:5002 \--cluster.agency-endpoint tcp://127.0.0.1:5003 \--database.directory dbserver1 &arangod --server.authentication=false \--server.endpoint tcp://0.0.0.0:6002 \--cluster.my-address tcp://127.0.0.1:6002 \--cluster.my-role DBSERVER \--cluster.agency-endpoint tcp://127.0.0.1:5001 \--cluster.agency-endpoint tcp://127.0.0.1:5002 \--cluster.agency-endpoint tcp://127.0.0.1:5003 \--database.directory dbserver2 &
Coordinators:
arangod --server.authentication=false \--server.endpoint tcp://0.0.0.0:7001 \--cluster.my-address tcp://127.0.0.1:7001 \--cluster.my-role COORDINATOR \--cluster.agency-endpoint tcp://127.0.0.1:5001 \--cluster.agency-endpoint tcp://127.0.0.1:5002 \--cluster.agency-endpoint tcp://127.0.0.1:5003 \--database.directory coordinator1 &
arangod --server.authentication=false \--server.endpoint tcp://0.0.0.0:7002 \--cluster.my-address tcp://127.0.0.1:7002 \--cluster.my-role COORDINATOR \--cluster.agency-endpoint tcp://127.0.0.1:5001 \--cluster.agency-endpoint tcp://127.0.0.1:5002 \--cluster.agency-endpoint tcp://127.0.0.1:5003 \
Note in particular that the endpoint descriptions given under --cluster.my-address and --cluster.agency-endpoint must not use the IP address because they must contain an actual address that can be routed to the corresponding server. The 0.0.0.0 in --server.endpoint simply means that the server binds itself to all available network devices with all available IP addresses.
Upon registering with the Agency during startup the Cluster will assign an ID to every server. The generated ID will be printed out to the log or can be accessed via the HTTP API by calling http://server-address/_admin/server/id.
The method from the previous paragraph can be extended to a more real production scenario, to start an ArangoDB Cluster on multiple machines. The only changes are that one has to replace all local addresses 127.0.0.1 by the actual IP address of the corresponding server. Obviously, it would no longer be necessary to use different port numbers on different servers.
Let’s assume that you want to start your ArangoDB Cluster with 3 Agents, 3 DB-Servers and 3 Coordinators on three different machines with IP addresses:
192.168.1.1192.168.1.2192.168.1.3
Let’s also suppose that each of the above machines runs an Agent, a DB-Server and a Coordinator
If we use:
- 8531 as port of the Agents
- 8530 as port of the DB-Servers
- 8529 as port of the Coordinators
then the commands you have to use are reported in the following subparagraphs.
On 192.168.1.1:
On 192.168.1.2:
arangod --server.endpoint tcp://0.0.0.0:8531 \--agency.my-address tcp://192.168.1.2:8531 \--server.authentication false \--agency.activate true \--agency.size 3 \--agency.supervision true \--database.directory agent
On 192.168.1.3:
arangod --server.endpoint tcp://0.0.0.0:8531 \--agency.my-address tcp://192.168.1.3:8531 \--server.authentication false \--agency.activate true \--agency.size 3 \--agency.endpoint tcp://192.168.1.1:8531 \--agency.endpoint tcp://192.168.1.2:8531 \--agency.endpoint tcp://192.168.1.3:8531 \--agency.supervision true \--database.directory agent
DB-Servers
In the commands below, note that DBSERVER, as value of the option --cluster.my-role, is allowed only from version 3.4; for previous versions, to start a DB-Server, please use PRIMARY as role.
On 192.168.1.1:
arangod --server.authentication=false \--server.endpoint tcp://0.0.0.0:8530 \--cluster.my-address tcp://192.168.1.1:8530 \--cluster.my-role DBSERVER \--cluster.agency-endpoint tcp://192.168.1.1:8531 \--cluster.agency-endpoint tcp://192.168.1.2:8531 \--cluster.agency-endpoint tcp://192.168.1.3:8531 \--database.directory dbserver &
On 192.168.1.2:
arangod --server.authentication=false \--server.endpoint tcp://0.0.0.0:8530 \--cluster.my-address tcp://192.168.1.2:8530 \--cluster.my-role DBSERVER \--cluster.agency-endpoint tcp://192.168.1.1:8531 \--cluster.agency-endpoint tcp://192.168.1.2:8531 \--cluster.agency-endpoint tcp://192.168.1.3:8531 \--database.directory dbserver &
On 192.168.1.3:
On 192.168.1.1:
--server.endpoint tcp://0.0.0.0:8529 \--cluster.my-role COORDINATOR \--cluster.agency-endpoint tcp://192.168.1.1:8531 \--cluster.agency-endpoint tcp://192.168.1.2:8531 \--cluster.agency-endpoint tcp://192.168.1.3:8531 \--database.directory coordinator &
On 192.168.1.2:
arangod --server.authentication=false \--server.endpoint tcp://0.0.0.0:8529 \--cluster.my-address tcp://192.168.1.2:8529 \--cluster.my-role COORDINATOR \--cluster.agency-endpoint tcp://192.168.1.1:8531 \--cluster.agency-endpoint tcp://192.168.1.2:8531 \--cluster.agency-endpoint tcp://192.168.1.3:8531 \--database.directory coordinator &
On 192.168.1.3:
arangod --server.authentication=false \--server.endpoint tcp://0.0.0.0:8529 \--cluster.my-address tcp://192.168.1.3:8529 \--cluster.my-role COORDINATOR \--cluster.agency-endpoint tcp://192.168.1.1:8531 \--cluster.agency-endpoint tcp://192.168.1.2:8531 \--cluster.agency-endpoint tcp://192.168.1.3:8531 \--database.directory coordinator &
Note 2: you can easily extend the Cluster, by adding more machines which run a DB-Server and a Coordiantor. For instance, if you have an additional forth machine with IP 192.168.1.4, you can execute the following commands
On 192.168.1.4:
arangod --server.authentication=false \--server.endpoint tcp://0.0.0.0:8530 \--cluster.my-address tcp://192.168.4.1:8530 \--cluster.my-role DBSERVER \--cluster.agency-endpoint tcp://192.168.1.1:8531 \--cluster.agency-endpoint tcp://192.168.1.2:8531 \--cluster.agency-endpoint tcp://192.168.1.3:8531 \--database.directory dbserver &arangod --server.authentication=false \--server.endpoint tcp://0.0.0.0:8529 \--cluster.my-address tcp://192.168.1.4:8529 \--cluster.my-role COORDINATOR \--cluster.agency-endpoint tcp://192.168.1.1:8531 \--cluster.agency-endpoint tcp://192.168.1.2:8531 \--cluster.agency-endpoint tcp://192.168.1.3:8531 \--database.directory coordinator &
Manually starting a Cluster via Docker is basically the same as described in the paragraphs above.
A bit of extra care has to be invested due to the way in which Docker isolates its network. By default it fully isolates the network and by doing so an endpoint like --server.endpoint tcp://0.0.0.0:8530 will only bind to all interfaces inside the Docker container which does not include any external interface on the host machine. This may be sufficient if you just want to access it locally but in case you want to expose it to the outside you must facilitate Dockers port forwarding using the -p command line option. Be sure to check the .
You can simply use the -p flag in Docker to make the individual processes available on the host machine or you could use Docker’s links to enable process intercommunication.
An example configuration might look like this:
This will start a DB-Server within a Docker container with an isolated network. Within the Docker container it will bind to all interfaces (this will be 127.0.0.1:8530 and some internal Docker IP on port 8530). By supplying -p 192.168.1.1:10000:8530 we are establishing a port forwarding from our local IP (192.168.1.1 port 10000 in this example) to port 8530 inside the container. Within the command we are telling arangod how it can be reached from the outside --cluster.my-address tcp://192.168.1.1:10000. This information will be forwarded to the Agency so that the other processes in your Cluster can see how this particular DB-Server may be reached.
Authentication
To start the official Docker container you will have to decide on an authentication method, otherwise the container will not start.
Provide one of the arguments to Docker as an environment variable. There are three options:
ARANGO_NO_AUTH=1
Disable authentication completely. Useful for local testing or for operating in a trusted network (without a public interface).
ARANGO_ROOT_PASSWORD=password
Start ArangoDB with the given password for root.
ARANGO_RANDOM_ROOT_PASSWORD=1
Let ArangoDB generate a random root password.
