ZooKeeper SystemD Service Unit File

zookeeper.service

[Unit]
Description=ZooKeeper Service
Documentation=http://zookeeper.apache.org
Requires=network.target
After=network.target

[Service]
Type=forking
User=zookeeper
Group=zookeeper
ExecStart=/opt/zookeeper/bin/zkServer.sh start /opt/zookeeper/conf/zookeeper.conf
ExecStop=/opt/zookeeper/bin/zkServer.sh stop /opt/zookeeper/conf/zookeeper.conf
ExecReload=/opt/zookeeper/bin/zkServer.sh restart /opt/zookeeper/conf/zookeeper.conf
WorkingDirectory=/var/lib/zookeeper

[Install]
WantedBy=default.target

this is just reusing the shell script

ExecStart=/opt/zookeeper/bin/zkServer.sh start-foreground /opt/zookeeper/conf/zookeeper.conf

ExecStart=/opt/zookeeper/bin/zkServer.sh start-foreground /opt/zookeeper/conf/zookeeper.conf

How does that help, and does it play nice with restart?

Usage: /usr/zookeeper/default/bin/zkServer.sh [--config <conf-dir>] {start|start-foreground|stop|restart|status|print-cmd}

ExecStart=/opt/zookeeper/bin/zkServer.sh --config /etc/opt/zookeeper start-foreground
ExecStop=/opt/zookeeper/bin/zkServer.sh --config /etc/opt/zookeeper stop
ExecReload=/opt/zookeeper/bin/zkServer.sh --config /etc/opt/zookeeper restart
WorkingDirectory=/var/lib/zookeeper

Is it a good idea to add ROLLINGFILE log level here?
log4j.properies is ignored always https://issues.apache.org/jira/browse/ZOOKEEPER-2170

mine working config file

[Unit]
Description=Zookeeper Daemon
Documentation=http://zookeeper.apache.org
Requires=network.target
After=network.target

[Service]    
Type=forking
WorkingDirectory=/opt/zookeeper
User=root
Group=root
ExecStart=/opt/zookeeper/bin/zkServer.sh start /opt/zookeeper/conf/zoo.cfg
ExecStop=/opt/zookeeper/bin/zkServer.sh stop /opt/zookeeper/conf/zoo.cfg
ExecReload=/opt/zookeeper/bin/zkServer.sh restart /opt/zookeeper/conf/zoo.cfg
TimeoutSec=30
Restart=on-failure

[Install]
WantedBy=default.target