Kubernetes Custom Resource Definitions (CRDs) Not Properly Updating or Being Applied

When dealing with custom resources in Kubernetes, one rare issue you may encounter is that Custom Resource Definitions (CRDs) are not properly updating or being applied to the cluster.

This can happen due to several reasons.

Start by ensuring that the CRD itself is correctly defined.

Run kubectl get crd <crd-name> to check if the CRD is correctly registered in the cluster.

If the CRD is not listed, you may have failed to apply the correct manifest for the CRD.

Apply the CRD using kubectl apply -f <crd-manifest.yaml> and check again.

If the CRD is present but the custom resources aren’t updating as expected, check the API server logs for potential errors related to CRDs or custom resource controllers.

Misconfigurations in the CRD schema could also prevent it from being applied properly, especially if there are validation errors in the fields.

Check the schema definition carefully, particularly the spec.validation.openAPIV3Schema section, to ensure that it matches your custom resource definitions.

If you are working with an operator or controller that interacts with the CRD, ensure that the operator is correctly implemented and running in the cluster.

Misconfigured or missing controllers can cause updates to CRDs to fail, leaving your custom resources in an inconsistent state.

Another cause could be issues with versioning.

If you're updating an existing CRD, ensure that the version in the CRD manifest is incremented correctly, and all resources using that CRD are updated accordingly.

In some cases, CRD updates might fail due to conflicting changes between versions.

If the problem persists, try deleting and recreating the CRD and associated custom resources, but be aware that this will result in the loss of data stored in the custom resources.