OpenSVC

Cluster Configuration

Upon agent installation, the node is considered part of its own 1-node cluster.

In /etc/opensvc/cluster.conf:

Bootstrap a new cluster

If the node joins an existing cluster, skip this section.

If the cluster seed node has no heartbeat setup, a unicast heartbeat with default settings will be automatically added on first join.

This default heartbeat requires every nodename to be resolved to an ip address reachable on 1215/tcp.

If this requirements are not met, you can setup one or more custom heartbeats on the seed node before joins.

For example, a custom heartbeat configuration would be:

    om cluster config update --set hb#1.type=unicast --set hb#1.port=1216

The new heartbeats are visible in the top section of the monitoring command output:

    om mon

Stonith is optional. Skip to the next section if not concerned.

On a new cluster, the stonith configuration can be applied on the first node. The joining nodes will fetch this configuration from this joined node.

For example, a dummy stonith configuration would be

om cluster config update --set stonith#node2.cmd=/bin/true

This configuration will execute :cmd:/bin/true on the node taking over a service which was previously running on the now stalled node2.

Good, isolated fencing packages are freely available. For one, https://github.com/ClusterLabs/fence-agents

Arbitrators are optional. Skip to the next section if not concerned.

The arbitrator configuration can be applied on any node of the cluster.

om cluster config update --set arbitrator#1.name=relay1 \
                      --set arbitrator#1.secret=10231023102310231023102310231023

This configuration will ask for the agent on node relay1 for its vote in a quorum race, if needed to get a majority.

The arbitrator#1.secret value comes from the cluster.secret value on the arbitrator relay1.

The joining node can choose to join any of the cluster node already joined.

On the joined node node1, generate a join token:

$ sudo om daemon auth --role join

On the joining node node2:

sudo om daemon join --token <token> --node node1

Note:

If the node was frozen before the join, it is left frozen after the join.
If the node was not frozen before the join, the join process freezes it. If the join is successful, the node is thawed. If not, the node is left frozen.

sudo om daemon leave