install zookeeper

wget http://apache.hippo.nl/zookeeper/zookeeper-3.4.12/zookeeper-3.4.12.tar.gz
tar -xf zookeeper-3.4.12.tar.gz
cat > zookeeper-3.4.12/conf/zoo.cfg <<- EOM
# 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.
# do not use /tmp for storage, /tmp here is just
# example sakes.
dataDir=/zookeeper
# the port at which the clients will connect
clientPort=2181
# the maximum number of client connections.
# increase this if you need to handle more clients
#maxClientCnxns=60
#
# Be sure to read the maintenance section of the
# administrator guide before turning on autopurge.
#
# http://zookeeper.apache.org/doc/current/zookeeperAdmin.html#sc_maintenance
#
# The number of snapshots to retain in dataDir
#autopurge.snapRetainCount=3
# Purge task interval in hours
# Set to "0" to disable auto purge feature
#autopurge.purgeInterval=1
EOM
mkdir -p /zookeeper

cat > /etc/systemd/system/zookeeper.service <<- EOM
[Unit]
Description=Zookeeper
After=network.target

[Service]
ExecStart=/opt/zookeeper-3.4.12/bin/zkServer.sh start
ExecStop=/opt/zookeeper-3.4.12/bin/zkServer.sh stop
Type=forking
Restart=on-failure

[Install]
WantedBy=multi-user.target

EOM