How to debug Systemd problems
If you are experiencing a problem with system boot up due to Systemd, please see the common bugs document before filing a bug. Some easy configuration tweaks that fix a wide range of issues may be listed there. If the problem you are seeing is not listed there or none of the workarounds seem to help, please consider filing a bug to help us make Fedora run better on your hardware.
Debugging systemd problems
To identify slow boot and look for the jobs that are "running" those jobs are the ones where boot waits for completion on and the ones that listed as "waiting" will be executed only after those which are "running" are completed.
systemctl list-units -t service --all
To list all available services and their current status
systemctl list-units -t service
To show all active services
systemctl status sshd.service
To examine the current runtime status of a service. (In the above example the ssh service)
systemctl list-units -t target --all
To show all available targets.
systemctl list-units -t target
To show all active targets.
systemctl show -p "Wants" multi-user.target
To see which services a target pulls in. ( In the above example the multi-user.target )
systemd --test --system --unit=multi-user.target
To examine what gets started when when booted into a specific target. ( In the above example the multi-user.target )
Systemd boot parameters
The following boot parameters are also available to further assist with debugging boot issues.
- Overrides the unit to activate on boot. This may be used to temporarily boot into a different boot unit, for example rescue.target or emergency.target. ( Defaults to default.target. )
- Takes a boolean argument. If true systemd dumps core when it crashes. Otherwise no core dump is created. ( Defaults to true )
- Takes a boolean argument. If true systemd spawns a shell when it crashes. Otherwise no core dump is created. Defaults to false, for security reasons, as the shell is not protected by any password authentication.
- Takes an integer argument. If positive systemd activates the specified virtual terminal when it crashes. ( Defaults to -1 )
- Takes a boolean argument. If true asks for confirmation when spawning processes. ( Defaults to false )
- Takes a boolean argument. If true shows terse service status updates on the console during bootup. ( Defaults to true )
- Takes a boolean argument. If true output of SysV init scripts will be directed to the console. ( Defaults to true, unless quiet is passed as kernel command line option in which case it defaults to false. )
- Set log target. Argument must be one of console, syslog, kmsg, syslog-or-kmsg, null.
- Set log level. As argument this accepts a numerical log level or the well-known syslog symbolic names (lowercase): emerg, alert, crit, err, warning, notice, info, debug.
- Highlight important log messages. Argument is a boolean value. If the argument is omitted it defaults to true.
- Include code location in log messages. This is mostly relevant for debugging purposes. Argument is a boolean value. If the argument is omitted it defaults to true.