Chapter 16. Creating caches with Data Grid Operator


Use Cache CRs to add cache configuration with Data Grid Operator and control how Data Grid stores your data.

16.1. Data Grid caches

Cache configuration defines the characteristics and features of the data store and must be valid with the Data Grid schema. Data Grid recommends creating standalone files in XML or JSON format that define your cache configuration. You should separate Data Grid configuration from application code for easier validation and to avoid the situation where you need to maintain XML snippets in Java or some other client language.

To create caches with Data Grid clusters running on OpenShift, you should:

  • Use Cache CR as the mechanism for creating caches through the OpenShift front end.
  • Use Batch CR to create multiple caches at a time from standalone configuration files.
  • Access Data Grid Console and create caches in XML or JSON format.

You can use Hot Rod or HTTP clients but Data Grid recommends Cache CR or Batch CR unless your specific use case requires programmatic remote cache creation.

Cache CRs

  • Cache CRs apply to Data Grid service pods only.
  • Each Cache CR corresponds to a single cache on the Data Grid cluster.

16.2. Creating caches with the Cache CR

Complete the following steps to create caches on Data Grid service clusters using valid configuration in XML or YAML format.

Procedure

  1. Create a Cache CR with a unique value in the metadata.name field.
  2. Specify the target Data Grid cluster with the spec.clusterName field.
  3. Name your cache with the spec.name field.

    Note

    The name attribute in the cache configuration does not take effect. If you do not specify a name with the spec.name field then the cache uses the value of the metadata.name field.

  4. Add a cache configuration with the spec.template field.
  5. Apply the Cache CR, for example:

    oc apply -f mycache.yaml
    cache.infinispan.org/mycachedefinition created

Cache CR examples

XML

apiVersion: infinispan.org/v2alpha1
kind: Cache
metadata:
  name: mycachedefinition
spec:
  clusterName: infinispan
  name: myXMLcache
  template: <distributed-cache mode="SYNC" statistics="true"><encoding media-type="application/x-protostream"/><persistence><file-store/></persistence></distributed-cache>

YAML

apiVersion: infinispan.org/v2alpha1
kind: Cache
metadata:
  name: mycachedefinition
spec:
  clusterName: infinispan
  name: myYAMLcache
  template: |-
    distributedCache:
      mode: "SYNC"
      owners: "2"
      statistics: "true"
      encoding:
        mediaType: "application/x-protostream"
      persistence:
        fileStore: ~

16.3. Updating caches with the Cache CR

You can control how Data Grid Operator handles modifications to the cache configuration in the Cache CR.

Data Grid Operator attempts to update the cache configuration on the Data Grid Server at runtime. If the update fails, Data Grid Operator uses one of the following strategies:

retain strategy
The Operator updates the status of the Cache CR to Ready=False. You can manually delete the Cache CR and create a new cache configuration. This is the default strategy.
recreate strategy

The Operator deletes the cache from the Data Grid cluster and creates a new cache with the latest spec.template value from the Cache CR.

Important

Configure the recreate strategy only if your deployment can tolerate data loss.

Prerequisites

  • Have a valid Cache CR.

Procedure

  1. Use the spec.updates.strategy field to set the Cache CR strategy.

    mycache.yaml

    spec:
      updates:
        strategy: recreate

  2. Apply changes to the Cache CR, for example:

    oc apply -f mycache.yaml

16.4. Adding persistent cache stores

You can add persistent cache stores to Data Grid service pods to save data to the persistent volume.

Data Grid creates a Single File cache store, .dat file, in the /opt/infinispan/server/data directory.

Procedure

  • Add the <file-store/> element to the persistence configuration in your Data Grid cache, as in the following example:

    <distributed-cache name="persistent-cache" mode="SYNC">
      <encoding media-type="application/x-protostream"/>
      <persistence>
        <file-store/>
      </persistence>
    </distributed-cache>
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