feat(tiller): Enhance Tiller pod search with labels

- Add labels to Tiller pod searching
- Add Tiller pod labels to default config options
- Add exception for case when Tiller pod cannot be found using labels
- Add exception for case when Tiller pod is not in running state
- Update exception documentation

Closes #172

Change-Id: I7e54c4b4a60638bca1073457c256030344832ef9

armada/conf/default.py

@@ -66,6 +66,11 @@ The Keystone project domain name used for authentication.
         default='/home/user/.ssh/',
         help=utils.fmt('Path to SSH private key.')),
 
+    cfg.StrOpt(
+        'tiller_pod_labels',
+        default='app=helm,name=tiller',
+        help=utils.fmt('Labels for the tiller pod.')),
+
     cfg.ListOpt(
         'tiller_release_roles',
         default=['admin'],

armada/exceptions/tiller_exceptions.py

@@ -123,6 +123,23 @@ class GetReleaseContentException(TillerException):
         super(GetReleaseContentException, self).__init__(message)
 
 
+class TillerPodNotFoundException(TillerException):
+    '''Exception that occurs when a tiller pod cannot be found using the
+       labels specified in the Armada config.
+    '''
+
+    def __init__(self, labels):
+        message = 'Could not find tiller pod with labels "{}"'.format(labels)
+
+        super(TillerPodNotFoundException, self).__init__(message)
+
+
+class TillerPodNotRunningException(TillerException):
+    '''Exception that occurs when no tiller pod is found in a running state'''
+
+    message = 'No tiller pods found in running state'
+
+
 class TillerVersionException(TillerException):
     '''Exception that occurs during a failed Release Testing'''
 

armada/handlers/tiller.py

@@ -99,12 +99,22 @@ class Tiller(object):
 
     def _get_tiller_pod(self):
         '''
-        Search all namespaces for a pod beginning with tiller-deploy*
+        Returns tiller pod using the tiller pod labels specified in the Armada
+        config
         '''
-        for i in self.k8s.get_namespace_pod('kube-system').items:
-            # TODO(alanmeadows): this is a bit loose
-            if i.metadata.name.startswith('tiller-deploy'):
-                return i
+        pods = self.k8s.get_namespace_pod('kube-system',
+                                          CONF.tiller_pod_labels).items
+        # No tiller pods found
+        if not pods:
+            raise ex.TillerPodNotFoundException(CONF.tiller_pod_labels)
+
+        # Return first tiller pod in running state
+        for pod in pods:
+            if pod.status.phase == 'Running':
+                return pod
+
+        # No tiller pod found in running state
+        raise ex.TillerPodNotRunningException()
 
     def _get_tiller_ip(self):
         '''

docs/source/operations/guide-exceptions.rst

@@ -31,6 +31,10 @@ Tiller Exceptions
 +------------------------------------+--------------------------------------------------------------------------------------------+
 | ReleaseUpdateException             | A release failed to update.                                                                |
 +------------------------------------+--------------------------------------------------------------------------------------------+
+| TillerPodNotFoundException         | Tiller pod could not be found using the labels specified in the Armada config.             |
++------------------------------------+--------------------------------------------------------------------------------------------+
+| TillerPodNotRunningException       | Tiller pod was found but is not in a running state.                                        |
++------------------------------------+--------------------------------------------------------------------------------------------+
 | TillerServicesUnavailableException | Occurs when Tiller services are unavailable.                                               |
 +------------------------------------+--------------------------------------------------------------------------------------------+
 

etc/armada/armada.conf.sample

@@ -25,6 +25,9 @@
 # Path to SSH private key. (string value)
 #ssh_key_path = /home/user/.ssh/
 
+# Labels for the tiller pod. (string value)
+#tiller_pod_labels = app=helm,name=tiller
+
 # IDs of approved API access roles. (list value)
 #tiller_release_roles = admin
 
@@ -88,6 +91,10 @@
 # log_config_append is set. (string value)
 #syslog_log_facility = LOG_USER
 
+# Use JSON formatting for logging. This option is ignored if log_config_append
+# is set. (boolean value)
+#use_json = false
+
 # Log output to standard error. This option is ignored if log_config_append is
 # set. (boolean value)
 #use_stderr = false
@@ -439,3 +446,20 @@
 # directories to be searched.  Missing or empty directories are ignored. (multi
 # valued)
 #policy_dirs = policy.d
+
+# Content Type to send and receive data for REST based policy check (string
+# value)
+# Allowed values: application/x-www-form-urlencoded, application/json
+#remote_content_type = application/x-www-form-urlencoded
+
+# server identity verification for REST based policy check (boolean value)
+#remote_ssl_verify_server_crt = false
+
+# Absolute path to ca cert file for REST based policy check (string value)
+#remote_ssl_ca_crt_file = <None>
+
+# Absolute path to client cert for REST based policy check (string value)
+#remote_ssl_client_crt_file = <None>
+
+# Absolute path client key file REST based policy check (string value)
+#remote_ssl_client_key_file = <None>