Launching an ArangoDB cluster on multiple machines

Essentially, one can use the method from the previous section to start an ArangoDB cluster on multiple machines as well. 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.

If we assume that you want to start you ArangoDB cluster on three different machines with IP addresses

192.168.1.1
192.168.1.2
192.168.1.3

then the commands you have to use are (you can use host names if they can be resolved to IP addresses on all machines):

On 192.168.1.1:

arangod --server.endpoint tcp://0.0.0.0:5001 --agency.my-address tcp://192.168.1.1:5001 --server.authentication false --agency.activate true --agency.size 3 --agency.supervision true --database.directory agency

On 192.168.1.2:

arangod --server.endpoint tcp://0.0.0.0:5001 --agency.my-address tcp://192.168.1.2:5001 --server.authentication false --agency.activate true --agency.size 3 --agency.supervision true --database.directory agency

On 192.168.1.3:

arangod --server.endpoint tcp://0.0.0.0:5001 --agency.my-address tcp://192.168.1.3:5001 --server.authentication false --agency.activate true --agency.size 3 --agency.endpoint tcp://192.168.1.1:5001 --agency.endpoint tcp://192.168.1.2:5001 --agency.endpoint tcp://192.168.1.3:5001 --agency.supervision true --database.directory agency

On 192.168.1.1:

arangod --server.authentication=false --server.endpoint tcp://0.0.0.0:8529 --cluster.my-address tcp://192.168.1.1:8529 --cluster.my-local-info db1 --cluster.my-role PRIMARY --cluster.agency-endpoint tcp://192.168.1.1:5001 --cluster.agency-endpoint tcp://192.168.1.2:5001 --cluster.agency-endpoint tcp://192.168.1.3:5001 --database.directory primary1 &

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-local-info db2 --cluster.my-role PRIMARY --cluster.agency-endpoint tcp://192.168.1.1:5001 --cluster.agency-endpoint tcp://192.168.1.2:5001 --cluster.agency-endpoint tcp://192.168.1.3:5001 --database.directory primary2 &

On 192.168.1.3:

arangod --server.authentication=false --server.endpoint tcp://0.0.0.0:8531 --cluster.my-address tcp://192.168.1.3:8531 --cluster.my-local-info coord1 --cluster.my-role COORDINATOR --cluster.agency-endpoint tcp://192.168.1.1:5001 --cluster.agency-endpoint tcp://192.168.1.2:5001 --cluster.agency-endpoint tcp://192.168.1.3:5001 --database.directory coordinator &

Obviously, it would no longer be necessary to use different port numbers on different servers. We have chosen to keep all port numbers in comparison to the local setup to minimize the necessary changes.

If you want to setup secondaries, the following commands will do the job:

On 192.168.1.2:

curl -f -X PUT --data '{"primary": "DBServer001", "oldSecondary": "none", "newSecondary": "Secondary001"}' -H "Content-Type: application/json" http://192.168.1.3:8531/_admin/cluster/replaceSecondary && arangod --server.authentication=false --server.endpoint tcp://0.0.0.0:8629 --cluster.my-id Secondary001 --cluster.my-address tcp://192.168.1.2:8629 --cluster.agency-endpoint tcp://192.168.1.1:5001 --cluster.agency-endpoint tcp://192.168.1.2:5001 --cluster.agency-endpoint tcp://192.168.1.3:5001 --database.directory secondary1 &

On 192.168.1.1:

curl -f -X PUT --data '{"primary": "DBServer002", "oldSecondary": "none", "newSecondary": "Secondary002"}' -H "Content-Type: application/json" http://localhost:8531/_admin/cluster/replaceSecondary && arangod --server.authentication=false --server.endpoint tcp://0.0.0.0:8630 --cluster.my-id Secondary002 --cluster.my-address tcp://192.168.1.1:8630 --cluster.agency-endpoint tcp://192.168.1.1:5001 --cluster.agency-endpoint tcp://192.168.1.2:5001 --cluster.agency-endpoint tcp://192.168.1.3:5001 --database.directory secondary2 &

Note that we have started the Secondary002 on the same machine as DBServer001 and Secondary001 on the same machine as DBServer002 to avoid that a complete pair is lost when a machine fails. Furthermore, note that ArangoDB does not yet perform automatic failover to the secondary, if a primary fails. This only works in the Apache Mesos setting. For synchronous replication, automatic failover always works and you do not need to setup secondaries for this.

After having swallowed these longish commands, we hope that you appreciate the simplicity of the setup with Apache Mesos and DC/OS.