Netdata init script for Synology DSM

rc.netdata

#!/bin/bash

# 1. Install this as `/usr/local/etc/rc.d/rc.netdata`
# 2. Create the directory `/volume1/netdata`
# 3. Symlink `/opt/netdata` to `/volume1/netdata`
# 4. Create a triggered task with Task Scheduler to call `/usr/local/etc/rc.d/rc.netdata start` at boot. 
#    - (You may have to turn on Advanced Mode in the Control Panel to see Task Scheduler)
# 5. Either reboot or run `sudo /usr/local/etc/rc.d/rc.netdata start` 

# If you get an error about "Connection Failed," then you've already run Netdata and filled `/`. 
# Stop netdata and move `/opt/netdata` to `/volume1/netdata` before continuing with step 3 above.

NETDATA_DIR=/opt/netdata
DAEMON=$NETDATA_DIR/bin/srv/netdata
TIMEOUT=30  # seconds to wait for netdata to exit

[ -x $DAEMON ] || exit 0

function get_pid() {
	pid=$( ps ax | grep -v grep | grep -m 1 $DAEMON | awk '{ print $1 }' )
}

function check_netdata() {
	count=1
	while [ $count -lt $TIMEOUT ]; do
		get_pid
		if [ -z $pid ]; then
			break
		else
			sleep 1
			count=$(( $count + 1))
		fi
	done

	if [ $count -eq $TIMEOUT ]; then
		echo "Timeout exceeded waiting for netdata to exit."
		echo "Use '$0 kill' to force netdata to exit."
		exit 1
	fi
}

function stop_netdata() {
	get_pid
	if [ "x$pid" != "x" ]; then
		if [ "x$1" = "xforce" ]; then
			kill -9 $pid
		else
			kill $pid
		fi
	else
		echo "No running netdata found."
	fi

}

function start_netdata() {
	get_pid
	if [ "x$pid" = "x" ]; then
		echo "Starting Netdata."
		$DAEMON
	else
		echo "Netdata already running with pid $pid"
	fi
}

case "$1" in
    start)
		start_netdata
    ;;
    stop)
		echo "Shutting down Netdata."
		stop_netdata
    ;;
	restart)
		echo "Shutting down Netdata."
		stop_netdata
		if [ "x$pid" != "x" ]; then
			echo "Waiting maximum of $TIMEOUT seconds for netdata to exit."
		fi
		check_netdata
		start_netdata
	;;
	kill)
		echo "Killing netdata."
		stop_netdata force
	;;
	status)
		get_pid
		if [ "x$pid" != "x" ]; then
			echo "Netdata running with PID $pid"
		else
			echo "No running netdata found."
		fi
	;;
    *)
        echo "Usage: $0 {start|stop|kill|restart|status}"
        exit 1
esac

exit 0

• ps ax shows all processes running on the host.
• grep -v grep excludes the grep command
• grep -m 1 $DAEMON returns the first match of whatever is in the variable $DAEMON
• awk '{ print $1 }' returns the first field (which is the pid)

The two grep lines were in the opposite order, which could, in an unusual circumstance, cause the grep line to be matched before $DAEMON and then excluded, resulting in no matches. Flipping it around ensures that only $DAEMON lines are included.

Doing it with square brackets is another way, but it's dependent on the shell. Using grep -v is consistent across any shell I might be working in, or any scripts that I write.

Can you explain why you think that "grep after ps does nothing?"

Ah, you were fixing this

It's possible, but only if grep -v $DAEMON is earlier in the process list than "$DAEMON" itself. The only way that can happen is if this script is run before netdata is started, in which case netdata isn't running and will be started by the script.

I guess I didn't read or understand. So grep -v grep is supposed to filter other grep $DAEMON command that is running at the same time but also started before Netdata. I am not sure this can happen. But thanks for your detailed explanation.

I agree that it's not likely to ever happen, since it would require that the grep command had a pid lower than the running netdata process. However, placing grep -v grep first in the chain changes "unlikely to happen" to "will never happen," and that seemed reasonable.

Synology DSM >= 6.1 no longer calls rc.local, so I've updated the script with new instructions.

First, don't let Netdata write to /opt/netdata because the DSM root partition is only ~2GB in size. Symlink /opt/netdata to /volume1/netdata.

Second, use Task Scheduler to create a Triggered Task that fires at boot and calls /usr/local/etc/rc.d/rc.netdata start. I'm not sure if /etc gets overwritten during DSM updates, but allegedly /usr/local/etc/rc.d is safe. I haven't tried an upgrade yet. Alternatively you can put it in /volume1/netdata and call it from there.

Synology DSM >= 6.1 no longer calls rc.local, so I've updated the script with new instructions.

First, don't let Netdata write to /opt/netdata because the DSM root partition is only ~2GB in size. Symlink /opt/netdata to /volume1/netdata.

Second, use Task Scheduler to create a Triggered Task that fires at boot and calls /usr/local/etc/rc.d/rc.netdata start. I'm not sure if /etc gets overwritten during DSM updates, but allegedly /usr/local/etc/rc.d is safe. I haven't tried an upgrade yet. Alternatively you can put it in /volume1/netdata and call it from there.

Hi, does auto update of netdata works using this solution for you?
I tried and after updating using kickstart script, netdata doesn't start anymore. Kickstart script creates a systemd service which seems to be having some issues due to symlink i think.

No idea. I don't use netdata anymore.