Cluster Operations

This section provides information on Eventing related cluster operations. For a complete information on cluster operations, refer to Cluster Operations

Rebalancing an Eventing Node

Eventing rebalance, similar to cluster rebalance, is a process of redistributing Eventing data among the available nodes.

In a normal scenario, all mutations in a node get assigned to workers that are available in the vBucket. When a new Eventing node gets added, the Eventing data is distributed between the available nodes.

During Eventing rebalance the metadata bucket plays a very crucial role. The metadata bucket stores checkpoint information about processed mutations before rebalancing. Post rebalance completion, using this checkpoint information, the Eventing service resumes to process mutations and ensures that no data mutations are lost during rebalancing.

Adding an Eventing node and rebalance is similar to cluster node addition and rebalancing, see Add a Node and Rebalance

The Function lifecycle operations (deploying, undeploying and deleting operations)
and the Eventing rebalance operation are mutually exclusive. The Eventing rebalance
operation fails when a Function lifecycle operation is currently in progress. Likewise,
when the Eventing rebalance operation is in progress, you cannot perform a Function
lifecycle operation.

Eventing Failover

Eventing nodes can be failed over and removed safely from a cluster during unavoidable downtime.

The Eventing failover results in loss of data mutations. It is recommended to exercise caution before triggering failover.

Steps to failover an Eventing node is similar to steps in the cluster node failover section, see Failing over a Node