Add config support for ZooKeeper servers

Allows defining a cluster of ZooKeeper servers within the nodepool
configuration file. Validation of the new config values is supported,
and the new values are documented.

Change-Id: I24401d08135a071dee1d00711fdd82c1d728b31a

doc/source/configuration.rst

@@ -152,6 +152,21 @@ Example::
 
 The ``port`` key is optional (default: 4730).
 
+zookeeper-servers
+-----------------
+Lists the ZooKeeper servers uses for coordinating information between
+nodepool workers. Example::
+
+  zookeeper-servers:
+    - host: zk1.example.com
+      port: 2181
+      chroot: /nodepool
+
+The ``port`` key is optional (default: 2181).
+
+The ``chroot`` key, used for interpreting ZooKeeper paths relative to
+the supplied root path, is also optional and has no default.
+
 .. _labels:
 
 labels

nodepool/cmd/config_validator.py

@@ -122,6 +122,11 @@ class ConfigValidator:
                 'host': str,
                 'port': int,
             }],
+            'zookeeper-servers': [{
+                'host': str,
+                'port': int,
+                'chroot': str,
+            }],
             'cron': cron,
             'providers': [providers],
             'labels': [labels],

nodepool/config.py

@@ -102,6 +102,10 @@ class GearmanServer(ConfigValue):
     pass
 
 
+class ZooKeeperServer(ConfigValue):
+    pass
+
+
 class DiskImage(ConfigValue):
     pass
 
@@ -128,6 +132,7 @@ def loadConfig(config_path):
     newconfig.jenkins_managers = {}
     newconfig.zmq_publishers = {}
     newconfig.gearman_servers = {}
+    newconfig.zookeeper_servers = {}
     newconfig.diskimages = {}
     newconfig.crons = {}
 
@@ -155,6 +160,14 @@ def loadConfig(config_path):
         g.name = g.host + '_' + str(g.port)
         newconfig.gearman_servers[g.name] = g
 
+    for server in config.get('zookeeper-servers', []):
+        z = ZooKeeperServer()
+        z.host = server['host']
+        z.port = server.get('port', 2181)
+        z.chroot = server.get('chroot', '')
+        z.name = z.host + '_' + str(z.port)
+        newconfig.zookeeper_servers[z.name] = z
+
     for provider in config.get('providers', []):
         p = Provider()
         p.name = provider['name']

nodepool/tests/fixtures/config_validate/good.yaml

@@ -19,6 +19,11 @@ zmq-publishers:
 gearman-servers:
   - host: zuul.openstack.org
 
+zookeeper-servers:
+  - host: zk1.openstack.org
+    port: 2181
+    chroot: /test
+
 labels:
   - name: devstack-precise
     image: devstack-precise

nodepool/tests/fixtures/config_validate/yaml_error.yaml

@@ -19,6 +19,9 @@ zmq-publishers:
 gearman-servers:
   - host: zuul.openstack.org
 
+zookeeper-servers:
+  - host: zk1.openstack.org
+
 labels:
   - name: devstack-precise
     image: devstack-precise

nodepool/tests/test_builder.py

@@ -147,7 +147,3 @@ class TestNodepoolBuilder(tests.DBTestCase):
                     # We failed to upload first_fail_id and have
                     # moved onto another upload that will fail.
                     break
-
-class TestZookeeper(tests.ZKTestCase):
-    def test_zk(self):
-        self.zkclient.get('/')