I am trying to do a simple kernel verifying systemd service.
Service is:
[Unit]
Description= It checks kernel version
[Service]
ExecStart=/home/handle-kernel-version.sh $EXPECTED_KERNEL $(uname -r)
StandardOutput=journal+console
EnvironmentFile=/home/input_kernel.txt
Type=oneshot
[Install]
WantedBy=multi-user.target
Problem is, the second argument is passed as $(uname instead of the actual kernel version. I suppose it is due to the systemd handling of escape character and I can surely bypass this issue by adding the uname line in the bash script itself, but I would like to know the solution for the oneline method nevertheless.
Related
I'm setting up Debian so that it works in kiosk mode. To do this, I created a service that performs the watchdog function:
[Unit]
Description=Watchdog for Myapp
After=getty#tty6.service
After=polkit.service
After=udisks2.service
[Service]
ExecStart=su user -c "startx /opt/myapp -- :0 vt5"
ExecStop=systemctl start xdm
Type=simple
Restart=on-failure
StartLimitInterval=60s
StartLimitBurst=5
RuntimeMaxSec=infinity
Environment="DISPLAY=:0"
Environment="XAUTHORITY=/home/user/.Xauthority"
Environment="XDG_VTNR=5"
[Install]
WantedBy=graphical.target
The problem is that ExecStart gets the exit code not from myapp, but from startx. I have tried many options, but I have not been able to come up with a way that would work as it should...
I tried trying to pass exit code through pipe, exit &? and writing the exit code to a file. But, apparently, my skills in bash are not enough to make the right command.
Googling also didn't help because to find a case in which people call starts directly from the root, and not from the user, which is why the transfer of exit code is much easier than in my case
I am tweaking snmpd systemd service and I want to execute a script in ExecStartPost. This will be an infinite loop script.
This script is an implementation of agentx ..
I have tried running in a normal manner with and without & , but after sometime the systemd service is timing out..
it is timing out expecting a exit status from the script is what is believe.
Is there any way to run the script in background without the systemd snmp service timing out ?
[Unit]
Description=Simple Network Management Protocol (SNMP) Daemon.
After=syslog.target network.target
[Service]
Type=notify
Environment=OPTIONS="-LS0-6d"
EnvironmentFile=-/etc/sysconfig/snmpd
ExecStart=/usr/sbin/snmpd $OPTIONS -f
ExecStartPost=/usr/bin/python /usr/local/bin/pyagent.py
ExecReload=/bin/kill -HUP $MAINPID
[Install]
WantedBy=multi-user.target
From reading the documentation, I believe you want to keep your & but add - prefix to skip result checking:
ExecStartPost=-/usr/bin/python /usr/local/bin/pyagent.py &
I have a program which is run by systemd with a service file like this:
[Unit]
Description=...
[Service]
Type=notify
ExecStart=/usr/sbin/myprogram
WatchdogSec=1
KillMode=process
KillSignal=SIGTERM
Restart=always
It sends the respective signal to the watchdog regularly. From time to time, the program seems to hang and is terminated by the watchdog, then restarts. Before the watchdog terminates it, I'd like to capture some information from the program by executing a command or running some other script (e.g. run gdb -p <PID> --batch -ex 'thread apply all backtrace'). How would I do this?
Add a ExecStop= to your service.
[Service]
ExecStart=....
ExecStop=/path/to/SomeOtherProgram
....
According to systemd manual, if ExecStop option is available, it will run that first, then if the process under ExecStart is still available after this, it will run the KillMode.
ExecStop=
Commands to execute to stop the service started via
ExecStart=. This argument takes multiple command lines, following the
same scheme as described for ExecStart= above. Use of this setting is
optional. After the commands configured in this option are run, it is
implied that the service is stopped, and any processes remaining for
it are terminated according to the KillMode= setting (see
systemd.kill(5)). If this option is not specified, the process is
terminated by sending the signal specified in KillSignal= when service
stop is requested. Specifier and environment variable substitution is
supported (including $MAINPID, see above).
EDIT
As in the comment below, this solution may not work for Watchdog option in the service file.
I have a bourne shell script (at my NAS) that handles the ffmpeg recording of all my ipcams. For switching the record time (etc) of some cams, that sh script should be restarted daily at 2 different hours (07:00am and 10:00pm), which is configured in the bash script and works well.
To start the sh script, I make use of systemd with the following .service file:
[Unit]
Description=record ipcams
After=tmp.mount network.target
Requires=network.target
RequiresMountsFor=/media/USB2
[Service]
Type=forking
PIDFile=/var/run/cams_record.pid
ExecStart=/bin/bash -c '/media/USB2/movie/cams/cams_record.sh'
TimeoutStopSec=1
Restart=always
[Install]
WantedBy=multi-user.target
So far so good. Now what I actually want, is to restart that script file daily at 07:00am and 10:00pm (or restart the previous mentioned .service at those two times) thus I thought to make use of a systemd timer. I created such a timer for 07:00 am (with the option: OnCalender=07:00)
Question is: having a (permanently running) service, how do I restart that service (and thus the script file) at 07:00am and 22:00pm. I can of course make use of 2 systemd timers (1 for 07:00am and 1 for 10:00pm), but is there a possibility to combine these; i.e. using 1 systemd timer for both times.
With a templates timers, you can do something like this
cat test#.timer
[Unit]
Description=test
[Timer]
OnCalendar=%i:00
Unit=test.service
[Install]
WantedBy=timers.target
Then :
systemctl daemon-reload
and
systemctl start test#07.service
systemctl start test#22.service
Source : https://fedoramagazine.org/systemd-template-unit-files/ and https://jason.the-graham.com/2013/03/06/how-to-use-systemd-timers/
You can use several OnCalendar in one timer, see documentation https://www.freedesktop.org/software/systemd/man/systemd.timer.html#OnCalendar=
[Unit]
Description=test
[Timer]
OnCalendar=07:00
OnCalendar=10:00
Unit=test.service
[Install]
WantedBy=timers.target
I'm running embedded linux on an Altera FPGA. It uses SystemD to run startup, and I have a script in the "multi-user.target.wants" section that runs my application.
When it runs from startup my code runs slower than when I run the identical script from an ssh shell.
I have checked that paths are the same, that permissions are correct on the scripts, that full paths are used in the scripts. Using 'top' I can see that priorities are set the same for the various threads started, yet somehow performance is completely different between the two ways of starting.
The script in full is:
#!/bin/sh
sleep 5s
mount /dev/mmcblk0p5 /home/root/linux
cd /home/root/linux/mem_driver
./memdev_load
cd /home/root/linux/gpio_driver
insmod ./gpiodev.ko
mknod /dev/gpiodev c 249 0
sleep 5s
cd /home/root/src/control
mysqld_safe &
up=0
while [ $up -ne 2 ]
do
up=$(pgrep mysql | wc -l);
echo $up
done
sleep 3s
cd /home/root/studio_web/myapp
npm start &
sleep 1s
cd /home/root/src/control
#sleep 1s
./control > /home/root/linux/output.log
various sleep commands have been inserted to try and make sure things start up in the right order.
Any help in diagnosing why this behaves differently would be greatly appreciated.
Is that the only shell script you are using? or do you have a systemd service file that executes that single shell script?
Using sleep is ineffective here. You should separate them into separate shell scripts and then use systemd to ensure that the shell scripts are run in order.
For example, we want to mount the directory first, because if this fails then nothing following will be successful. So we create a systemd mount service:
# home-root-linux.mount
[Unit]
Description=Mount /home/root/linux
Before=gpiodev.service
[Mount]
What=/dev/mmcblk0p5
Where=/home/root/linux
Options=defaults
[Install]
WantedBy=multi-user.target
Then we can create another systemd service which depends on the mount above before executing the three parts of the shell script which were previously separated by sleep to ensure that they were run in order.
# gpiodev.service
[Unit]
Description=Handle gpiodev kernel module
After=home-root-linux.mount
Before=mysqlsafe.service
[Service]
Type=oneshot
ExecStartPre=/home/root/linux/mem_driver/memdev_load
ExecStart=/sbin/insmod gpiodev.ko; /bin/mknod /dev/gpiodev c 249 0
WorkingDirectory=/home/root/linux/gpio_driver
RemainAfterExit=yes
StandardOutput=journal
[Install]
WantedBy=multi-user.target
Second part of the systemd service (following the sleep). We have a separate shellscript which is placed in /sbin/ in this example as it contains a while loop so it would be best to separate this:
# mysqlsafe.service
[Unit]
Description=MySQL safe
After=gpiodev.service
Before=npmoutput.service
[Service]
Type=oneshot
ExecStart=/sbin/mysqlsafe.sh
WorkingDirectory=/home/root/src/control
RemainAfterExit=yes
StandardOutput=journal
[Install]
WantedBy=multi-user.target
Second part of the shell script which is executed in the systemd service above (separated to a separate file due to the complexity):
# /sbin/mysqlsafe.sh
#!/bin/sh
mysqld_safe &
up=0
while [ $up -ne 2 ]
do
up=$(pgrep mysql | wc -l);
echo $up
done
Third part of the systemd service (the third section of the original shell script which was separated by sleep):
# mpmoutput.service
[Unit]
Description=npm and output to log
After=mysqlsafe.service
[Service]
Type=oneshot
ExecStartPre=/usr/bin/npm &
ExecStart=/home/root/src/control > /home/root/linux/output.log
WorkingDirectory=/home/root/studio_web/myapp
RemainAfterExit=yes
StandardOutput=journal
[Install]
WantedBy=multi-user.target
The idea behind this approach is that systemd recognises the importance of each service and the reliance upon the following service i.e. if one service fails the following services in queue will not execute. You can then check this using systemctl and see logging in journalctl.
Just a quick copy, paste and edit. Could contain errors as it was not tested or checked.
More reading can be found here regarding systemd service files: https://www.freedesktop.org/software/systemd/man/systemd.service.html