Running ZNC as a system daemon

Note: if you just want to run ZNC automatically, when server is turned on, look here instead.

New User

We first create a new user so that there is a separation of concerns. This separation gives us many security benefits. The new user will have a shell that cannot be logged into so there is no threat of a remote attack or someone sitting at the computer. Also the user will have reduced privileges and therefore can only access files for which it has ownership or is part of the group. We create this new user by issuing the following command (I added a comment field for later system administrators):

sudo useradd --create-home -d /var/lib/znc --system --shell /sbin/nologin --comment "Account to run ZNC daemon" --user-group znc

Though we cannot ourselves login to this user, we can have the system assign the user a process. This also helps identify who is running which processes in the "Task Manager" per se. Creating a new user is not necessary, but as you can see there are many reasons for doing so.

Making a new home

Now that we have a new user, we have to create the data directory that our ZNC server will store its configurations. Since our initialization scripts will be looking for the configuration in /var/lib/znc that's where we have to tell ZNC to make them.

• Make the configuration we will run at startup:

sudo -u znc /usr/bin/znc --datadir=/var/lib/znc --makeconf

Create the init.d Scripts

Once our new user and configuration files have been created, we have to create the initialization script. These scripts might have already been created for you by the package manager. There are two main platforms for Linux, Fedora and Debian. Fedora is like your CentOS and Red Hat distros, while Debian's most notable distro is Ubuntu. There is a difference between the two scripts, so only use the one you need.

Fedora-based machines

• Here is the /etc/init.d/znc for Fedora-based machines:

#!/bin/sh
#
# znc - Advanced IRC Bouncer INIT script #
# description: An Advanced IRC bouncer INIT script for
# Source function library.
. /etc/rc.d/init.d/functions

exec=/usr/bin/znc
prog=znc
config=/var/lib/znc
runas=znc

lockfile=/var/lock/subsys/$prog

start() {
	[ -x $exec ] || exit 5
	echo -n $"Starting $prog: "
	# if not running, start it up here, usually something like "daemon $exec"
	daemon --user $runas "$exec -d $config >/dev/null 2>&1"
	# If you're reckless with your system, comment the line above and
	# uncomment this one below... I just don't get it why
	# daemon "$exec -r -d $config >/dev/null 2>&1"
	retval=$?
	echo
	[ $retval -eq 0 ] && touch $lockfile
	return $retval
}

stop() {
	echo -n $"Stopping $prog: "
	# stop it here, often "killproc $prog"
	killproc $prog -TERM
	retval=$?
	echo
	[ $retval -eq 0 ] && rm -f $lockfile
	return $retval
}

reload() {
	echo -n $"Reloading $prog: "
	# stop it here, often "killproc $prog"
	killproc $prog -HUP
	retval=$?
	echo
}

restart() {
	stop
	start
}

rh_status() {
	# run checks to determine if the service is running or use generic status
	status $prog
}

rh_status_q() {
	rh_status >/dev/null 2>&1
}

case "$1" in
	start)
		rh_status_q && exit 0
		$1
		;;
	stop)
		rh_status_q || exit 0
		$1
		;;
	restart)
		$1
		;;
	reload)
		rh_status_q || exit 7
		$1
		;;
	status)
		rh_status
		;;
	condrestart|try-restart)
		rh_status_q || exit 0
		restart
		;;
	*)
		echo $"Usage: $0 {start|stop|status|reload|restart|condrestart|try-restart}"
		exit 2
esac
exit $?

Debian-based machines

• Here is the /etc/init.d/znc for Debian-based machines:

#! /bin/sh
### BEGIN INIT INFO
# Provides:          znc
# Required-Start:    $remote_fs $syslog
# Required-Stop:     $remote_fs $syslog
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: ZNC IRC bouncer
# Description:       ZNC is an IRC bouncer
### END INIT INFO
 
PATH=/sbin:/usr/sbin:/bin:/usr/bin
DESC="ZNC daemon"
NAME=znc
DAEMON=/usr/bin/$NAME
DATADIR=/var/lib/znc
DAEMON_ARGS="--datadir=$DATADIR"
PIDDIR=/var/run/znc
PIDFILE=$PIDDIR/$NAME.pid
SCRIPTNAME=/etc/init.d/$NAME
USER=znc
GROUP=znc

# Exit if the package is not installed
[ -x "$DAEMON" ] || exit 0

# Read configuration variable file if it is present
[ -r /etc/default/$NAME ] && . /etc/default/$NAME

# Load the VERBOSE setting and other rcS variables
. /lib/init/vars.sh

# Define LSB log_* functions.
# Depend on lsb-base (>= 3.2-14) to ensure that this file is present
# and status_of_proc is working.
. /lib/lsb/init-functions

#
# Function that starts the daemon/service
#
do_start()
{
	# Return
	#   0 if daemon has been started
	#   1 if daemon was already running
	#   2 if daemon could not be started
	if [ ! -d $PIDDIR ]
	then
		mkdir $PIDDIR
	fi
	chown $USER:$GROUP $PIDDIR
	start-stop-daemon --start --quiet --pidfile $PIDFILE --exec $DAEMON --test --chuid $USER > /dev/null || return 1
	start-stop-daemon --start --quiet --pidfile $PIDFILE --exec $DAEMON --chuid $USER -- $DAEMON_ARGS > /dev/null || return 2
}

#
# Function that stops the daemon/service
#
do_stop()
{
	# Return
	#   0 if daemon has been stopped
	#   1 if daemon was already stopped
	#   2 if daemon could not be stopped
	#   other if a failure occurred
	start-stop-daemon --stop --quiet --retry=TERM/30/KILL/5 --pidfile $PIDFILE --name $NAME --chuid $USER
	RETVAL="$?"
	[ "$RETVAL" = 2 ] && return 2
	# Wait for children to finish too if this is a daemon that forks
	# and if the daemon is only ever run from this initscript.
	# If the above conditions are not satisfied then add some other code
	# that waits for the process to drop all resources that could be
	# needed by services started subsequently.  A last resort is to
	# sleep for some time.
	start-stop-daemon --stop --quiet --oknodo --retry=0/30/KILL/5 --exec $DAEMON --chuid $USER
	[ "$?" = 2 ] && return 2
	# Many daemons don't delete their pidfiles when they exit.
	rm -f $PIDFILE
	return "$RETVAL"
}

#
# Function that sends a SIGHUP to the daemon/service
#
do_reload() {
	start-stop-daemon --stop --signal 1 --quiet --pidfile $PIDFILE --name $NAME --chuid $USER
	return 0
}

case "$1" in
  start)
	[ "$VERBOSE" != no ] && log_daemon_msg "Starting $DESC" "$NAME"
	do_start
	case "$?" in
		0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
		2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
	esac
	;;
  stop)
	[ "$VERBOSE" != no ] && log_daemon_msg "Stopping $DESC" "$NAME"
	do_stop
	case "$?" in
		0|1) [ "$VERBOSE" != no ] && log_end_msg 0 ;;
		2) [ "$VERBOSE" != no ] && log_end_msg 1 ;;
	esac
	;;
  status)
	status_of_proc -p $PIDFILE "$DAEMON" "$NAME" && exit 0 || exit $?
	;;
  reload)
	log_daemon_msg "Reloading $DESC" "$NAME"
	do_reload
	log_end_msg $?
	;;
  restart)
	log_daemon_msg "Restarting $DESC" "$NAME"
	do_stop
	case "$?" in
	  0|1)
		do_start
		case "$?" in
			0) log_end_msg 0 ;;
			1) log_end_msg 1 ;; # Old process is still running
			*) log_end_msg 1 ;; # Failed to start
		esac
		;;
	  *)
		# Failed to stop
		log_end_msg 1
		;;
	esac
	;;
  *)
	echo "Usage: $SCRIPTNAME {status|start|stop|reload|restart}" >&2
	exit 3
	;;
esac

After you've created the script, you must give it the proper permissions to run

sudo chmod 755 /etc/init.d/znc

Create the systemd script

• Create the file: /etc/systemd/system/znc.service

 [Unit]
 Description=ZNC, an advanced IRC bouncer
 After=network.target
    
 [Service]
 ExecStart=/usr/bin/znc -f --datadir=/var/lib/znc
 User=znc
    
 [Install]
 WantedBy=multi-user.target

Get the daemon up and running

Everything is now in place! Once we insert the daemon, you can either start the service yourself (as shown below) or restart the computer for the daemon to take its place.

• Insert the script into the boot sequence:

sudo update-rc.d znc defaults    # For Debian systems

• Start the service:

sudo service znc start

• Verify that the service is running:

sudo service znc status