Watchdog

I use watchdog to monitor my RPI. Do services go offline or the RPI is not responding, watchdog kicks in and restart the system. Now I also want watchdog to watch my Linbpq. This is possible with watchdog, watchdog looks at a PID file. As far as I know, no PID file is created when starting Linbpq.

Now there is a possibility that when starting Linbpq with systemd a command can be given so that a PID file is created.

This is my linbpq.service file from systemd

pd9q@packet:~ $ sudo cat /etc/systemd/system/linbpq.service
[Unit]
Description=Linbpq Daemon
After=network.target
After=direwolf.target
StartLimitInterval=0

[Service]
Type=simple
Restart=always
RestartSec=5
ExecStartPost=/bin/sh -c "echo $MAINPID > /home/pd9q/linbpq/run/linbpq.pid"
ExecStart=/bin/bash /home/pd9q/linbpq/linbpq.start
WorkingDirectory=/home/pd9q/linbpq

[Install]
WantedBy=multi-user.target
Alias=linbpq.service

This command creates a linbpq.pid file, now it is possible that watchdog monitors linbpq.

ExecStartPost=/bin/sh -c "echo $MAINPID > /home/pd9q/linbpq/run/linbpq.pid"
pd9q@packet:~ $ sudo ls -l /home/pd9q/linbpq/run
-rw-r--r-- 1 root root 4 Oct 14 18:36 linbpq.pid
pd9q@packet:~ $

At the end of my watchdog configuration file (/etc/watchdog.conf) I have added the following line.

# Check if Linbpq is running
pidfile         = /home/pd9q/linbpq/run/linbpq.pid

Take a look at what happens when you stop Linbpq.

sudo systemctl stop linbpq.service

Yes the system is ReBoOtInG (I hoop)