From remote cnpg

We can create a new cluster from an existing cnpg cluster.

Requirements

In the source and destination cluster we need the same:

• the same major PostgreSQL release with imageName or imageCatalogRef
• the same hardware architecture
• the same tablespaces

We also need

• enough max_wal_senders
• network connectivity between them

Importing the streaming_replica creds

We will use the streaming_replica role in the source cluster.

In order to get the credentials there, go to the namespace where the source cluster is located an export the secret that ends with "-replication"

kubectl get secret OMMITED-replication -o yaml

Then clean it and leave it this way

apiVersion: v1
data:
  tls.crt: OMMITED
  tls.key: OMMITED
kind: Secret
metadata:
  name: OMMITED-replication
type: kubernetes.io/tls

Go to the namespace where the new cluster will be created and import the secret

kubectl apply -f mysecret.yaml

The new cluster

Then create the new cluster with this basic settings

apiVersion: postgresql.cnpg.io/v1
kind: Cluster
metadata:
  name: cnpg
spec:
  imageCatalogRef: # or imageName
    apiGroup: postgresql.cnpg.io
    kind: ClusterImageCatalog
    major: 15 # must be the same major PostgreSQL
    name: postgresql
  externalClusters:
    - name: my-remote-cluster # descriptive name
      connectionParameters:
        host: my-remote-host # host or ip
        user: streaming_replica
        sslmode: require
      sslKey:
        name: OMMITED-replication
        key: tls.key
      sslCert:
        name: OMMITED-replication
        key: tls.crt
  bootstrap:
    pg_basebackup:
      source: my-remote-cluster
      # Next settings if we can create a database, owner and assign credentials to that user
      database: desired-db
      owner: db-owner-name
      secret:
        name: desired-db-secret

Links

• Bootstrap from a live cluster (pg_basebackup)

https://cloudnative-pg.io/documentation/1.26/bootstrap/#requirements

• SSL Support

https://www.postgresql.org/docs/current/libpq-ssl.html