[Unit]
Description=ClickHouse Server (analytic DBMS for big data)
Requires=network-online.target
# NOTE: that After/Wants=time-sync.target is not enough, you need to ensure
# that the time was adjusted already, if you use systemd-timesyncd you are
# safe, but if you use ntp or some other daemon, you should configure it
# additionaly.
After=time-sync.target network-online.target
Wants=time-sync.target

[Service]
Type=notify

# NOTE: we leave clickhouse watchdog process enabled to be able to see OOM/SIGKILL traces in clickhouse-server.log files.
# If you wish to disable the watchdog and rely on systemd logs just add "Environment=CLICKHOUSE_WATCHDOG_ENABLE=0" line.
User=clickhouse
Group=clickhouse
Restart=always
RestartSec=30
# The following ClickHouse directives should be used instead of forcing SIGKILL by systemd:
# - shutdown_wait_unfinished_queries
# - shutdown_wait_unfinished
TimeoutStopSec=infinity
# Disable forwarding signals by watchdog, since with default systemd's
# kill-mode control-group, systemd will send signal to all process in cgroup.
Environment=CLICKHOUSE_WATCHDOG_NO_FORWARD=1
# Since ClickHouse is systemd aware default 1m30sec may not be enough
TimeoutStartSec=0
# %p is resolved to the systemd unit name
RuntimeDirectory=%p 
ExecStart=/usr/bin/clickhouse-server --config=/etc/clickhouse-server/config.xml --pid-file=%t/%p/%p.pid
# Minus means that this file is optional.
EnvironmentFile=-/etc/default/%p
# Bring back /etc/default/clickhouse for backward compatibility
EnvironmentFile=-/etc/default/clickhouse
LimitCORE=infinity
LimitNOFILE=500000
CapabilityBoundingSet=CAP_NET_ADMIN CAP_IPC_LOCK CAP_SYS_NICE CAP_NET_BIND_SERVICE
AmbientCapabilities=CAP_NET_ADMIN CAP_IPC_LOCK CAP_SYS_NICE CAP_NET_BIND_SERVICE

[Install]
# ClickHouse should not start from the rescue shell (rescue.target).
WantedBy=multi-user.target