Zookeeper for DLM scenarios

In Tokyo, there was a cross project session on distributed
key locking:
https://etherpad.openstack.org/p/mitaka-cross-project-dlm

In support of the discussion there, we'll need support for
a zookeeper service in Devstack and ability to use libraries
like Tooz for DLM functionality.

In this review, we pick up some configuration files from
monasca-api and copy the lib/template to implement the
zookeeper lifecycle. Those services that need zookeeper
need to add "zookeeper" in ENABLED_SERVICES.

Change-Id: Icef26e5cdaa930a581e27d330e47706776a7f98f
diff --git a/files/zookeeper/zoo.cfg b/files/zookeeper/zoo.cfg
new file mode 100644
index 0000000..b8f5582
--- /dev/null
+++ b/files/zookeeper/zoo.cfg
@@ -0,0 +1,74 @@
+#
+# (C) Copyright 2015 Hewlett Packard Enterprise Development Company LP
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# http://hadoop.apache.org/zookeeper/docs/current/zookeeperAdmin.html
+
+# The number of milliseconds of each tick
+tickTime=2000
+# The number of ticks that the initial
+# synchronization phase can take
+initLimit=10
+# The number of ticks that can pass between
+# sending a request and getting an acknowledgement
+syncLimit=5
+# the directory where the snapshot is stored.
+dataDir=/var/lib/zookeeper
+# Place the dataLogDir to a separate physical disc for better performance
+# dataLogDir=/disk2/zookeeper
+
+# the port at which the clients will connect
+clientPort=2181
+
+# Maximum number of clients that can connect from one client
+maxClientCnxns=60
+
+# specify all zookeeper servers
+# The fist port is used by followers to connect to the leader
+# The second one is used for leader election
+
+server.0=127.0.0.1:2888:3888
+
+# To avoid seeks ZooKeeper allocates space in the transaction log file in
+# blocks of preAllocSize kilobytes. The default block size is 64M. One reason
+# for changing the size of the blocks is to reduce the block size if snapshots
+# are taken more often. (Also, see snapCount).
+#preAllocSize=65536
+
+# Clients can submit requests faster than ZooKeeper can process them,
+# especially if there are a lot of clients. To prevent ZooKeeper from running
+# out of memory due to queued requests, ZooKeeper will throttle clients so that
+# there is no more than globalOutstandingLimit outstanding requests in the
+# system. The default limit is 1,000.ZooKeeper logs transactions to a
+# transaction log. After snapCount transactions are written to a log file a
+# snapshot is started and a new transaction log file is started. The default
+# snapCount is 10,000.
+#snapCount=1000
+
+# If this option is defined, requests will be will logged to a trace file named
+# traceFile.year.month.day.
+#traceFile=
+
+# Leader accepts client connections. Default value is "yes". The leader machine
+# coordinates updates. For higher update throughput at thes slight expense of
+# read throughput the leader can be configured to not accept clients and focus
+# on coordination.
+#leaderServes=yes
+
+# Autopurge every hour to avoid using lots of disk in bursts
+# Order of the next 2 properties matters.
+# autopurge.snapRetainCount must be before autopurge.purgeInterval.
+autopurge.snapRetainCount=3
+autopurge.purgeInterval=1
\ No newline at end of file