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How to enable systemd debug shell in command line?
systemd.debug-shell=1 on the kernel command line. Tip: If you find yourself in a situation where you cannot use systemctl to communicate with a running systemd (e.g. when setting this up from a different booted system), you can avoid communication with the manager by specifying –root=: systemctl –root=/ enable debug-shell.service
How to increase verbosity of systemd command line?
Boot with these parameters on the kernel command line: in order to increase the verbosity of systemd, to let systemd write its logs to the kernel log buffer, to increase the size of the kernel log buffer, and to prevent the kernel from discarding messages. After reaching the shell, look at the log:
How to ask systemd to log debugging information?
If you have a hardware serial console available or if you are debugging in a virtual machine (e.g. using virt-manager you can switch your view to a serial console in the menu View -> Text Consoles or connect from the terminal using virsh console MACHINE ), you can ask systemd to log lots of useful debugging information to it by booting with:
Is it possible to run the debug shell always?
Leaving the root shell always available would be a security risk. It is also possible to alias kbrequest.target to debug-shell.service to start the debug shell on demand. This has the same security implications, but avoids running the shell always.
Is there command to debug ordering cycles in systemd?
To my knowledge, there is no such command. Actually systemd offers nothing to aid in debugging ordering cycles (sigh). According to journalctl, cvol.service wants basic.service, except that it doesn’t, at least not obviously.
What happens when systemd spawns a shell?
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.