Clustering

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Starting with version 0.9.3, InfluxDB supports arbitrarily sized clusters that need not be fully replicated. Additionally new data nodes can be added to a cluster. The first three nodes to join a cluster are raft peers. All subsequent nodes are data nodes and do not participate in consensus.

Configuration

The following is the current recommended procedure for configuring a cluster.

Note: You should always use the most recent release for clustering as there are significant improvements with each release. Do not attempt a cluster with InfluxDB versions prior to 0.9.3.

Start the Initial Raft Cluster

Throughout this example, each node will be given a number that denotes the order in which it was started (e.g. 1 for the first node, 2 for the second node, etc.). It is also assumed that you are running some version of Linux and while it is possible to build a cluster locally, it is not recommended.

1. Install InfluxDB on the 3 machines following the installation guide. Do not start the daemon on any of the machines.
2. For each node’s /etc/influxdb/influxdb.conf file, replace hostname = "localhost" with your host’s actual name. This hostname must be resolved by all members in the cluster. It can be an IP or a hostname and optional port number if necessary.
3. For each node’s /etc/influxdb/influxdb.conf file, update the bind-address to another port if 8088 is unacceptable. The bind-address can also specify the host interface IP to use (e.g. 10.0.1.10:8088). By default it will bind on all interfaces. Note that the port may differ from node to node (e.g. one can use 8088, another use 9099, and the other 10101).
4. Start InfluxDB on the first node, sudo service influxdb start (or sudo systemctl start influxdb if you are using systemd).
5. In /etc/default/influxdb on the second node, set INFLUXD_OPTS="-join hostname_1:port_1". If the file does not exist, create it.
6. Start InfluxDB on the second node, sudo service influxdb start (or sudo systemctl start influxdb if you are using systemd).
7. In /etc/default/influxdb on the third node, set INFLUXD_OPTS="-join hostname_1:port_1,hostname_2:port_2". If the file does not exist, create it.
8. Start InfluxDB on the third node, sudo service influxdb start (or sudo systemctl start influxdb if you are using systemd).

Note: As an alternative to steps 3 and 4, an additional -hostname host[:port] flag may be provided to INFLUXD_OPTS.

At this point you’ll want to verify that that your initial raft cluster is healthy. To do this, issue a SHOW SERVERS query to each node in your raft cluster. You should see something along the lines of this:

Note: The CLI output of SHOW SERVERS looks like this

show servers
id    cluster_addr            raft
1     hostname_1:port_1       true
2     hostname_2:port_2       true
3     hostname_3:port_3       true

If you do not see all three raft nodes, your cluster is not healthy. If you believe that you did the following steps correctly, but are still experiencing problems, try restarting each node in your cluster. If your problems persist, uninstall InfluxDB on each machine and retry steps 1 through 8. Under no circumstance should you continue setting up your cluster if your initial raft cluster is not healthy.

Note: If you’re having a hard time setting up your cluster, try setting the /var/lib/influxdb/meta/peers.json file manually to be ["<hostname 1>:<port 1>","<hostname 2>:<port 2>","<hostname 3>:<port 3>"].

Add More Data Nodes

Once you have verified that your raft cluster is healthy and running appropriately, extra data nodes can be added.

1. Install InfluxDB on the new node.
2. In the new node’s /etc/influxdb/influxdb.conf file, replace hostname = "localhost" with the nodes hosts actual name. This hostname must be resolved by all members in the cluster. It can be an IP or a hostname and optional port number if necessary.
3. In the new node’s /etc/influxdb/influxdb.conf file, update the bind-address to another port if 8088 is unacceptable. The bind-address can also specify the host interface IP to use (e.g. 10.0.1.10:8088). By default it will bind on all interfaces. Note that the port may differ from node to node (e.g. one can use 8088, another use 9099, and the other 10101).
4. In the new node’s /etc/default/influxdb file, set INFLUXD_OPTS="-join hostname_1:port_1,hostname_2:port_2". If the file does not exist, create it.
5. Start InfluxDB on the new node, sudo service influxdb start (or sudo systemctl start influxdb if you are using systemd).

Note: When using the -join you need only specify one hostname:port pair. However, if more than one is provided, Influx will try to connect with the additional pairs in the case that it cannot connect with the first one.

Note: As an alternative to steps 2 and 3, an additional -hostname host[:port] flag may be provided to INFLUXD_OPTS.

To verify that the new node has successfully joined the cluster, issue a SHOW SERVERS query to one of the nodes in the cluster. You should see something along the lines of this:

If you do not, then your node was not successfully added to the cluster. Please verify that your cluster is healthy and retry steps 1 through 3.

Unimplemented Features

• Configuring which nodes participate in raft consensus after the first three nodes form a cluster is not currently possible. For now, all new nodes are data-only nodes.
• Removing raft nodes.