Configuring cross-site replication on Replica instances

When the Operator creates a new cluster, a lot of things are happening, such as electing the Primary, generating certificates, and picking specific names. This should not happen if we want the Operator to run the Replica site, so first of all the cluster should be put into unmanaged state by setting the unmanaged key in the deploy/cr.yaml configuration file to true. Also you should set updateStrategy key to OnDelete and backup.enabled to false, because Smart Updates and backups are not allowed on unmanaged clusters.

Note

Setting unmanaged to true will not only prevent the Operator from controlling the Replica Set configuration, but it will also result in not generating certificates and users credentials for new clusters.

Here is an example:

spec:
  unmanaged: true
  updateStrategy: OnDelete
  replsets:
  - name: rs0
    size: 3
    ...
  backup:
    enabled: false
  ...

The Main and Replica sites should have the same Secrets objects, so don’t forget to apply Secrets from your Main site. Names of the corresponding objects are set in the secrets.ssl, secrets.sslInternal, secrets.users, and secrets.keyfile Custom Resource options (my-cluster-name-ssl, my-cluster-name-ssl-internal, my-cluster-name-secrets, and my-cluster-name-mongodb-keyfile by default).

Note

Replica will not start if the TLS secrets and the encryption key are not copied. If users are not copied, the replica will join the replica set, but it will be restarting due to failed liveness checks.

Copy your secrets from an existing cluster and apply each of them on your Replica site as follows:

$  kubectl apply -f my-cluster-secrets.yaml

The Replica site will be ready for replication when you apply changes as usual:

$ kubectl apply -f deploy/cr.yaml

Note

Don’t forget that you need to expose instances of the Replica cluster!

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Last update: 2024-11-15