Operator-SDK: Create a group of objects that can be queried together

Operator-SDK CustomResourceDefinition categories groups

2 min read | by Jordi Prats

When you have several kubernetes objects (CRDs) that work together it can be useful to be able to query them all together to get a better idea of what's deployed without having to query all the individial resources. With operator-SDK we just need to annotate the objects.

To do so we just need to annotate the main struct with //+kubebuilder:resource, for example:

//+kubebuilder:resource:categories="postgres"

We can add multiple categories by using the ; separator as follows:

//+kubebuilder:object:root=true
//+kubebuilder:subresource:status
//+kubebuilder:resource:categories="postgres";"servicecatalog"

// PgCluster is the Schema for the mskclusters API
type PgCluster struct {
  metav1.TypeMeta   `json:",inline"`
  metav1.ObjectMeta `json:"metadata,omitempty"`

  Spec   PgClusterSpec   `json:"spec,omitempty"`
  Status PgClusterStatus `json:"status,omitempty"`
}

As soon as we generate the manifests and install them in the cluster (make install) we'll be able to query all the objects that have the same group with kubectl get:

$ kubectl get postgres
NAME                                      PG CLUSTER   ADMIN   SYNC STATUS
pguser.msk.pet2cattle.com/operator-user   sample       true    in-sync
pguser.msk.pet2cattle.com/developer       sample               in-sync

NAME                                    CLUSTER NAME   SYNC STATUS
pgcluster.msk.pet2cattle.com/sample     sample         in-sync

Posted on 01/08/2023

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