Chapter 5. Stopping and Starting Data Grid Clusters

Stop and start Data Grid clusters with Data Grid Operator.

Cache definitions

Both Cache service and Data Grid service store permanent cache definitions in persistent volumes so they are still available after cluster restarts.

Data

Data Grid service nodes can write all cache entries to persistent storage during cluster shutdown if you add a file-based cache store.

5.1. Shutting Down Data Grid Clusters

Shutting down Cache service nodes removes all data in the cache. For Data Grid service nodes, you should configure the storage size for Data Grid service nodes to ensure that the persistent volume can hold all your data.

If the available container storage is less than the amount of memory available to Data Grid service nodes, Data Grid writes the following exception to logs and data loss occurs during shutdown: 

WARNING: persistent volume size is less than memory size. Graceful shutdown may not work.

Procedure

  • Set the value of replicas to 0 and apply the changes. 
spec:
  replicas: 0

5.2. Restarting Data Grid Clusters

Complete the following procedure to restart Data Grid clusters after shutdown.

Prerequisites

For Data Grid service nodes, you must restart clusters with the same number of nodes before shutdown. For example, you shut down a cluster of 6 nodes. When you restart that cluster, you must specify 6 as the value for spec.replicas.

This allows Data Grid to restore the distribution of data across the cluster. When all nodes in the cluster are running, you can then add or remove nodes.

You can find the correct number of nodes for Data Grid clusters as follows: 

$ oc get infinispan example-infinispan -o=jsonpath='{.status.replicasWantedAtRestart}'

Procedure

  • Set the value of spec.replicas to the appropriate number of nodes for your cluster, for example: 

    spec:
  replicas: 6