Labels and annotations

Labels and annotations are used to attach additional metadata information to Kubernetes resources.

Labels and annotations are rather similar. The difference between them is that labels are used by Kubernetes to identify and select objects, while annotations are assigning additional non-identifying information to resources. Therefore, typical role of Annotations is facilitating integration with some external tools.

Setting labels and annotations in the Custom Resource

You can set labels and/or annotations as key/value string pairs in the Custom Resource metadata section of the deploy/cr.yaml. For PostgreSQL, pgBouncer and pgBackRest Pods, use instances.metadata.annotations/instances.metadata.labels, proxy.pgbouncer.metadata.annotations/proxy.pgbouncer.metadata.labels, or backups.pgbackrest.metadata.annotations/backups.pgbackrest.metadata.labels keys as follows:

apiVersion: pgv2.percona.com/v2
kind: PerconaPGCluster
...
spec:
...
  instances:
   - name: instance1
     replicas: 3
     metadata:
      annotations:
        my-annotation: value1
      labels:
        my-label: value2
    ...

For PostgreSQL and pgBouncer Services, use expose.annotations/expose.labels or proxy.pgbouncer.expose.annotations/proxy.pgbouncer.expose.labels keys as follows:

apiVersion: pgv2.percona.com/v2
kind: PerconaPGCluster
...
spec:
  ...
  expose:
    annotations:
      my-annotation: value1
    labels:
      my-label: value2
    ...

The easiest way to check which labels are attached to a specific object with is using the additional --show-labels option of the kubectl get command. Checking the annotations is not much more difficult: it can be done as in the following example:

$ kubectl get service cluster1-pgbouncer -o jsonpath='{.metadata.annotations}'

Settings labels and annotations to the Operator Pod

You can assign labels and/or annotations to the Pod of the Operator itself by editing the deploy/operator.yaml configuration file before applying it during the installation.

apiVersion: apps/v1
kind: Deployment
...
spec:
...
  template:
    metadata:
      labels:
        app.kubernetes.io/component: operator
        app.kubernetes.io/instance: percona-postgresql-operator
        app.kubernetes.io/name: percona-postgresql-operator
        app.kubernetes.io/part-of: percona-postgresql-operator
        pgv2.percona.com/control-plane: postgres-operator
        ...

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Last update: 2024-04-17