Merge pull request #65187 from kwmonroe/feature/goal-state-status

Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

juju charms: set more accurate status based on goal_state

**What this PR does / why we need it**:
Use juju goal-state to report more accurate charm status.

**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes https://github.com/juju-solutions/bundle-canonical-kubernetes/issues/593

**Special notes for your reviewer**:
The goal-state hook tool was released in juju 2.4.  For deployments on earlier versions of juju, this will fall back to the current status reporting behavior.

**Release note**:

```release-note
Report accurate status for kubernetes-master and -worker charms.
```

cluster/juju/layers/kubernetes-master/reactive/kubernetes_master.py

@@ -396,12 +396,25 @@ def set_app_version():
 @hookenv.atexit
 def set_final_status():
     ''' Set the final status of the charm as we leave hook execution '''
+    try:
+        goal_state = hookenv.goal_state()
+    except NotImplementedError:
+        goal_state = {}
+
     if not is_state('kube-api-endpoint.available'):
-        hookenv.status_set('blocked', 'Waiting for kube-api-endpoint relation')
+        if 'relations' in goal_state and 'kube-api-endpoint' in goal_state['relations']:
+            status = 'waiting'
+        else:
+            status = 'blocked'
+        hookenv.status_set(status, 'Waiting for kube-api-endpoint relation')
         return
 
     if not is_state('kube-control.connected'):
-        hookenv.status_set('blocked', 'Waiting for workers.')
+        if 'relations' in goal_state and 'kube-control' in goal_state['relations']:
+            status = 'waiting'
+        else:
+            status = 'blocked'
+        hookenv.status_set(status, 'Waiting for workers.')
         return
 
     upgrade_needed = is_state('kubernetes-master.upgrade-needed')

cluster/juju/layers/kubernetes-worker/reactive/kubernetes_worker.py

@@ -1009,6 +1009,16 @@ def missing_kube_control():
     missing.
 
     """
+    try:
+        goal_state = hookenv.goal_state()
+    except NotImplementedError:
+        goal_state = {}
+
+    if 'relations' in goal_state and 'kube-control' in goal_state['relations']:
+        hookenv.status_set(
+            'waiting',
+            'Waiting for kubernetes-master to become ready')
+    else:
         hookenv.status_set(
             'blocked',
             'Relate {}:kube-control kubernetes-master:kube-control'.format(