dev: How to modify the status subresource with `kubectl edit` (CRD)

The following content is for the debugging purpose only.

Longhorn uses status subresource in the various CRs to separate the responsibility of spec and status. But an unintended result is, it's not possible to modify the status subresource directly using kubectl edit, which results in difficulty when debugging.

To modify the status subresource manually, here we use a Longhorn volume as an example. The same applies to all status subresources:

1. Run kubectl -n longhorn-system -v=7 edit volumes.longhorn.io pvc-1fa0fff5-5b05-4ac5-9c8c-76ce481fb8ca

2. Perform the edit.

3. At the end of the output, you will see something like this:

   I0811 11:01:48.825636   43355 request.go:942] Request Body: {"status":{"state":"attaching"}}
   I0811 11:01:48.825708   43355 round_trippers.go:416] PATCH https://rancher-master/k8s/clusters/c-sff4g/apis/longhorn.io/v1beta1/namespaces/longhorn-system/volumes/pvc-1fa0fff5-5b05-4ac5-9c8c-76ce481fb8ca
   I0811 11:01:48.825716   43355 round_trippers.go:423] Request Headers:
   I0811 11:01:48.825721   43355 round_trippers.go:426]     Accept: application/json
   I0811 11:01:48.825724   43355 round_trippers.go:426]     Content-Type: application/merge-patch+json
   I0811 11:01:48.825729   43355 round_trippers.go:426]     User-Agent: kubectl/v1.14.1 (linux/amd64) kubernetes/b739410
   I0811 11:01:48.825732   43355 round_trippers.go:426]     Authorization: Bearer kubeconfig-xxxx
   

4. Use the following curl command to update the status:

   curl -XPATCH -H "[Accept]" -H "[Content-Type]" -H "[Authorization]" --data '[Request Body]' [URL]/status

   For example, the command of above example is:

   curl -XPATCH -H "Accept: application/json" -H "Content-Type: application/merge-patch+json" -H "Authorization: Bearer kubeconfig-xxxx" --data '{"status":{"state":"attaching"}}' https://rancher-master/k8s/clusters/c-sff4g/apis/longhorn.io/v1beta1/namespaces/longhorn-system/volumes/pvc-1fa0fff5-5b05-4ac5-9c8c-76ce481fb8ca/status You might also need -k to skip the SSL validation.

Kubernetes issue: https://github.com/kubernetes/kubectl/issues/564