Syncronize WAN replicated data

WAN syncronization allows you to overcome out-of-sync issues with WAN replicated data.

See Synchronizing WAN clusters for more detailed information about the configuration and behavior of WAN syncronization in Hazelcast.

tip

For a worked example, see the Synchronize WAN replicated data tutorial.

Prerequisites for WAN syncronization

Before you create and configure a WanSync resource, you must create the following:

• At least one Hazelcast resource and one Map resource for the source Hazelcast cluster.
• A target Hazelcast cluster that is accessible from the source cluster.
• A WanReplication CR that points to the target cluster.

Configure the WAN syncronization resource

To configure WAN syncronization, you must create a WanSync resource. For more detailed information, see the API reference.

To create a WanSync resource you must use the existing WanReplication CR. This means that the WanSync resource reuses the existing and running WAN replication process.

Example of WanSync using the existing WanReplication

yaml

apiVersion: hazelcast.com/v1alpha1
kind: WanSync
metadata:
  name: wansync-sample
spec:
  wanReplicationResourceName: wan-replication-sample

Configure delta WAN syncronization

To configure delta WAN syncronization for the Hazelcast cluster, do the following:

• Configure Merkle tree for the Map resource.
• Set syncConsistencyCheckStrategy to MERKLE_TREES in the WanReplication resource.
• Create the WanSync resource. The created WanSync automatically uses Delta WAN Synchronization.

Example of delta WAN syncronization

yaml

apiVersion: hazelcast.com/v1alpha1
kind: Map
metadata:
  name: map-sample
spec:
  hazelcastResourceName: hazelcast
  merkleTree:
    depth: 10
---
apiVersion: hazelcast.com/v1alpha1
kind: WanReplication
metadata:
  name: wan-replication-sample
spec:
  resources:
  - name: map-sample
    kind: Map
  targetClusterName: dev
  endpoints: "198.51.100.252"
  syncConsistencyCheckStrategy: "MERKLE_TREES"
---
apiVersion: hazelcast.com/v1alpha1
kind: WanSync
metadata:
  name: wansync-sample
spec:
  wanReplicationResourceName: wan-replication-sample

Checking the status of a WAN syncronization

After creating the WanSync resource, run the following command to see the WAN syncronization status:

shell

kubectl get wansync wansync-sample

The output is similar to the following:

NAME                     STATUS
wansync-sample-sample    Completed