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= Setting up an early debug shell = | |||
In case of boot-time problems with systemd, it is useful to have a root shell available for debugging. | In case of boot-time problems with systemd, it is useful to have a root shell available for debugging. | ||
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* Enable it using <code>systemctl enable debug-shell.service</code> | * Enable it using <code>systemctl enable debug-shell.service</code> | ||
{{admon/tip|Manual enabling|If you find yourself in a situation where you cannot use systemctl (e.g. when setting this up from a different booted system), you can enable the service manually: | |||
<pre>cd $PATH_TO_FEDORA_ROOT/etc/systemd/system | |||
mkdir sysinit.target.wants | |||
ln -s ../debug-shell.service sysinit.target.wants/</pre>}} | |||
* Next time when booting, you will be able to switch to tty9 using CTRL+ALT+F9 and have a root shell there available from an early point in the booting process. | * Next time when booting, you will be able to switch to tty9 using CTRL+ALT+F9 and have a root shell there available from an early point in the booting process. | ||
{{admon/warning|Use it only for debugging!|Do not forget to disable debug-shell.service after you've finished debugging your boot problems. Leaving the root shell always available would be a security risk.}} | |||
Revision as of 08:28, 11 May 2012
Setting up an early debug shell
In case of boot-time problems with systemd, it is useful to have a root shell available for debugging.
- Save the following unit as /etc/systemd/system/debug-shell.service
[Unit] Description=early root shell on tty9 for debugging DefaultDependencies=no IgnoreOnIsolate=yes [Service] Environment=TERM=linux ExecStart=/usr/bin/openvt -f -c 9 -e /usr/bin/bash Restart=always RestartSec=0 TTYPath=/dev/tty9 TTYReset=yes TTYVHangup=yes KillMode=process IgnoreSIGPIPE=no # bash ignores SIGTERM KillSignal=SIGHUP # Unset locale for the console getty since the console has problems # displaying some internationalized messages. Environment=LANG= LANGUAGE= LC_CTYPE= LC_NUMERIC= LC_TIME= LC_COLLATE= LC_MONETARY= LC_MESSAGES= LC_PAPER= LC_NAME= LC_ADDRESS= LC_TELEPHONE= LC_MEASUREMENT= LC_IDENTIFICATION= [Install] WantedBy=sysinit.target
- Enable it using
systemctl enable debug-shell.service
Manual enabling
If you find yourself in a situation where you cannot use systemctl (e.g. when setting this up from a different booted system), you can enable the service manually:
If you find yourself in a situation where you cannot use systemctl (e.g. when setting this up from a different booted system), you can enable the service manually:
cd $PATH_TO_FEDORA_ROOT/etc/systemd/system mkdir sysinit.target.wants ln -s ../debug-shell.service sysinit.target.wants/
- Next time when booting, you will be able to switch to tty9 using CTRL+ALT+F9 and have a root shell there available from an early point in the booting process.
Use it only for debugging!
Do not forget to disable debug-shell.service after you've finished debugging your boot problems. Leaving the root shell always available would be a security risk.
Do not forget to disable debug-shell.service after you've finished debugging your boot problems. Leaving the root shell always available would be a security risk.