By default, when you enable Coherence Persistence, the required infrastructure in terms
of persistent volumes (PV) and persistent volume claims (PVC) is set up automatically. Also, the persistence-mode
is set to active. This allows the Coherence cluster to be restarted and the data to be retained.
This sample shows how to enable Persistence with all the defaults
under store.persistence in the coherence chart, values.yaml. Refer to this sample
for more details about setting other values such as storageClasses.
Return to Persistence samples / Return to Coherence Deployments samples / Return to samples
Ensure that you have installed Coherence Operator by following the instructions here.
Install the Coherence cluster.
$ helm install \
--namespace sample-coherence-ns \
--name storage \
--set clusterSize=3 \
--set cluster=persistence-cluster \
--set imagePullSecrets=sample-coherence-secret \
--set logCaptureEnabled=false \
--set store.persistence.enabled=true \
--set store.snapshot.enabled=true \
coherence/coherence
You may also change the size of the default directories:
/persistence default 2Gi - --set store.persistence.size=10Gi
/snapshot default 2Gi - --set store.snapshot.size-10Gi
Ensure that the pods are running, by using the following command:
$ kubectl get pods -n sample-coherence-ns
When all the three pods are in the Running state, proceed to check the PVC.
NAME READY STATUS RESTARTS AGE
coherence-operator-66f9bb7b75-hqk4l 1/1 Running 0 13m
storage-coherence-0 1/1 Running 0 3m
storage-coherence-1 1/1 Running 0 2m
storage-coherence-2 0/1 Running 0 44s
Run the following command to check the PVC created:
$ kubectl get pvc -n sample-coherence-ns
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
persistence-volume-storage-coherence-0 Bound pvc-a3fa6ce3-6588-11e9-bad6-025000000001 2Gi RWO hostpath 44m
persistence-volume-storage-coherence-1 Bound pvc-d2f732e7-6588-11e9-bad6-025000000001 2Gi RWO hostpath 43m
persistence-volume-storage-coherence-2 Bound pvc-fc175ea1-6588-11e9-bad6-025000000001 2Gi RWO hostpath 41m
snapshot-volume-storage-coherence-0 Bound pvc-a3fb2172-6588-11e9-bad6-025000000001 2Gi RWO hostpath 44m
snapshot-volume-storage-coherence-1 Bound pvc-d2f89ce9-6588-11e9-bad6-025000000001 2Gi RWO hostpath 43m
snapshot-volume-storage-coherence-2 Bound pvc-fc13ae4b-6588-11e9-bad6-025000000001 2Gi RWO hostpath 41m
Add data to the cluster.
a. Connect to the Coherence console using the following command to create a cache:
$ kubectl exec -it --namespace sample-coherence-ns storage-coherence-0 bash /scripts/startCoherence.sh console
b. At the Map (?): prompt, type cache test. This creates a cache in the service, PartitionedCache.
c. Use the following to add 50,000 objects of size 1024 bytes, starting at index 0 and using batches of 100:
bulkput 50000 1024 0 100
Mon Apr 15 07:37:03 GMT 2019: adding 500000 items (starting with #0) each 1024 bytes ...
Mon Apr 15 07:37:15 GMT 2019: done putting (11578ms, 8878KB/sec, 8637 items/sec)
At the prompt, type size and it should show 50000.
d. Create a snapshot of the PartitionedCache service which contains the cache test. This is for later use.
snapshot create test-snapshot
Issuing createSnapshot for service PartitionedCache and snapshot test-snapshot
Success
snapshot list
Snapshots for service PartitionedCache
test-snapshot
To exit the console, type bye or CTRL-C.
Delete the Coherence cluster by using helm delete:
$ helm delete storage --purge
Before continuing, ensure that the pods are deleted using the following command:
$ kubectl get pods -n sample-coherence-ns
Ensure that there are no pods running with the name coherence-storage-*.
Run the following command to ensure that the PVC still exists:
$ kubectl get pvc -n sample-coherence-ns
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
persistence-volume-storage-coherence-0 Bound pvc-a3fa6ce3-6588-11e9-bad6-025000000001 2Gi RWO hostpath 44m
persistence-volume-storage-coherence-1 Bound pvc-d2f732e7-6588-11e9-bad6-025000000001 2Gi RWO hostpath 43m
persistence-volume-storage-coherence-2 Bound pvc-fc175ea1-6588-11e9-bad6-025000000001 2Gi RWO hostpath 41m
snapshot-volume-storage-coherence-0 Bound pvc-a3fb2172-6588-11e9-bad6-025000000001 2Gi RWO hostpath 44m
snapshot-volume-storage-coherence-1 Bound pvc-d2f89ce9-6588-11e9-bad6-025000000001 2Gi RWO hostpath 43m
snapshot-volume-storage-coherence-2 Bound pvc-fc13ae4b-6588-11e9-bad6-025000000001 2Gi RWO hostpath 41m
Reinstall the Coherence cluster with Persistence enabled, using the following command:
$ helm install \
--namespace sample-coherence-ns \
--name storage \
--set clusterSize=3 \
--set cluster=storage-tier-cluster \
--set imagePullSecrets=sample-coherence-secret \
--set logCaptureEnabled=false \
--set store.persistence.enabled=true \
--set store.snapshot.enabled=true \
coherence/coherence
Wait until all the three pods are running before you continue to the next step.
Ensure that the data previously added still exists.
a. Connect to the Coherence console using the following:
$ kubectl exec -it --namespace sample-coherence-ns storage-coherence-0 bash /scripts/startCoherence.sh console
b. At the Map (?): prompt, type cache test. This creates/uses a cache in the service, PartitionedCache.
c. At the prompt, type size and it should show 50000.
This shows that the previous data entered has automatically been recovered as the PVC was honoured.
Note: There is currently a bug with default /persistence mount not being created on Docker for Mac environments, and therefore the size may show zero.
d. Clear the cache using the clear command and confirm that the cache size is zero.
Recover the `test-snapshot` using:
snapshot recover test-snapshot
The size of the cache should now be 50000.
To exit the console, type bye.
Run the following commands to delete the chart installed in this sample.
$ helm delete storage --purge
After deleting the pods, run the following command to delete the PVC:
$ kubectl get pvc -n sample-coherence-ns | sed 1d | awk '{print $1}' | xargs kubectl delete pvc -n sample-coherence-ns
persistentvolumeclaim "persistence-volume-storage-coherence-0" deleted
persistentvolumeclaim "persistence-volume-storage-coherence-1" deleted
persistentvolumeclaim "persistence-volume-storage-coherence-2" deleted
persistentvolumeclaim "snapshot-volume-storage-coherence-0" deleted
persistentvolumeclaim "snapshot-volume-storage-coherence-1" deleted
persistentvolumeclaim "snapshot-volume-storage-coherence-2" deleted
$ kubectl get pvc -n sample-coherence-ns
No resources found.
Before starting another sample, ensure that all pods are removed from the previous sample. To remove coherence-operator, use the helm delete command.