feat(health checks): implement new kubernetes 1.2 health check features

rootfs/api/models/config.py

@@ -38,8 +38,19 @@ def healthcheck(self):
         timeout = int(self.values.get('HEALTHCHECK_TIMEOUT', 50))
         delay = int(self.values.get('HEALTHCHECK_INITIAL_DELAY', 50))
         port = int(self.values.get('HEALTHCHECK_PORT', 5000))
-
-        return {'path': path, 'timeout': timeout, 'delay': delay, 'port': port}
+        period_seconds = int(self.values.get('HEALTHCHECK_PERIOD_SECONDS', 10))
+        success_threshold = int(self.values.get('HEALTHCHECK_SUCCESS_THRESHOLD', 1))
+        failure_threshold = int(self.values.get('HEALTHCHECK_FAILURE_THRESHOLD', 3))
+
+        return {
+            'path': path,
+            'timeout': timeout,
+            'delay': delay,
+            'port': port,
+            'period_seconds': period_seconds,
+            'success_threshold': success_threshold,
+            'failure_threshold': failure_threshold,
+        }
 
     def set_healthchecks(self):
         """Defines default values for HTTP healthchecks"""
@@ -49,10 +60,25 @@ def set_healthchecks(self):
         # fetch set health values and any defaults
         # this approach allows new health items to be added without issues
         health = self.healthcheck()
+
+        # HTTP GET related
         self.values['HEALTHCHECK_URL'] = health['path']
+        self.values['HEALTHCHECK_PORT'] = health['port']
+
+        # Number of seconds after which the probe times out.
+        # More info: http://releases.k8s.io/HEAD/docs/user-guide/pod-states.md#container-probes
         self.values['HEALTHCHECK_TIMEOUT'] = health['timeout']
+        # Number of seconds after the container has started before liveness probes are initiated.
+        # More info: http://releases.k8s.io/HEAD/docs/user-guide/pod-states.md#container-probes
         self.values['HEALTHCHECK_INITIAL_DELAY'] = health['delay']
-        self.values['HEALTHCHECK_PORT'] = health['port']
+        # How often (in seconds) to perform the probe.
+        self.values['HEALTHCHECK_PERIOD_SECONDS'] = health['period_seconds']
+        # Minimum consecutive successes for the probe to be considered successful
+        # after having failed.
+        self.values['HEALTHCHECK_SUCCESS_THRESHOLD'] = health['success_threshold']
+        # Minimum consecutive failures for the probe to be considered failed after
+        # having succeeded.
+        self.values['HEALTHCHECK_FAILURE_THRESHOLD'] = health['failure_threshold']
 
     def save(self, **kwargs):
         """merge the old config with the new"""

rootfs/scheduler/__init__.py

@@ -986,7 +986,15 @@ def _delete_rc(self, namespace, name):
 
         return response
 
-    def _healthcheck(self, controller, routable=False, path='/', port=5000, delay=30, timeout=5):  # noqa
+    def _healthcheck(self, controller, routable=False, path='/', port=5000, delay=30, timeout=5,
+                     period_seconds=1, success_threshold=1, failure_threshold=3):  # noqa
+        """
+        Apply HTTP GET healthcehck to the application container
+
+        http://kubernetes.io/docs/user-guide/walkthrough/k8s201/#health-checking
+        http://kubernetes.io/docs/user-guide/pod-states/#container-probes
+        http://kubernetes.io/docs/user-guide/liveness/
+        """
         if not routable:
             return controller
 
@@ -1011,7 +1019,10 @@ def _healthcheck(self, controller, routable=False, path='/', port=5000, delay=30
                 # length of time to wait for a pod to initialize
                 # after pod startup, before applying health checking
                 'initialDelaySeconds': delay,
-                'timeoutSeconds': timeout
+                'timeoutSeconds': timeout,
+                'periodSeconds': period_seconds,
+                'successThreshold': success_threshold,
+                'failureThreshold': failure_threshold,
             },
             'readinessProbe': {
                 # an http probe
@@ -1022,7 +1033,10 @@ def _healthcheck(self, controller, routable=False, path='/', port=5000, delay=30
                 # length of time to wait for a pod to initialize
                 # after pod startup, before applying health checking
                 'initialDelaySeconds': delay,
-                'timeoutSeconds': timeout
+                'timeoutSeconds': timeout,
+                'periodSeconds': period_seconds,
+                'successThreshold': success_threshold,
+                'failureThreshold': failure_threshold,
             },
         }