Webhooks require network connectivity between the Kubernetes API server and the operator. If the creation of an Elasticsearch resource times out with an error message similar to the following, then the Kubernetes API server might be unable to connect to the webhook to validate the manifest.

Error from server (Timeout): error when creating "elasticsearch.yaml": Timeout: request did not complete within requested timeout 30s

If you encounter the above error, try re-running the command with a higher request timeout as follows:

kubectl --request-timeout=1m apply -f elasticsearch.yaml

As the default failurePolicy of the webhook is Ignore, the above command should succeed after about 30 seconds. This is an indication that the API server cannot contact the webhook server and has foregone validation when creating the resource. One possible reason for this is that a network policy might be blocking any incoming requests to the webhook server. Consult your system administrator to determine whether that is the case and create an appropriate policy to allow communication between the Kubernetes API server and the webhook server. For example, the following network policy simply opens up the webhook port to the world:

kind: NetworkPolicy
apiVersion: networking.k8s.io/v1
metadata:
  name: allow-webhook-access-from-any
  namespace: elastic-system
spec:
  podSelector:
    matchLabels:
      control-plane: elastic-operator
  ingress:
  - from: []
    ports:
      - port: 9443

You may want to restrict webhook access to just the Kubernetes API server. Currently this requires knowing the IP address of the API server — which can be obtained through the command:

kubectl cluster-info | grep master

Assuming that the API server IP address is 10.1.0.1, the following policy restricts webhook access to just the API server.

kind: NetworkPolicy
apiVersion: networking.k8s.io/v1
metadata:
  name: allow-webhook-access-from-apiserver
  namespace: elastic-system
spec:
  podSelector:
    matchLabels:
      control-plane: elastic-operator
  ingress:
  - from:
      - ipBlock:
          cidr: 10.1.0.1/32
    ports:
      - port: 9443