systemd-getty-generator - Man Page

/usr/lib/systemd/system-generators/systemd-getty-generator

systemd-getty-generator is a generator that automatically instantiates serial-getty@​.service on the kernel consoles, if they can function as ttys and are not provided by the virtual console subsystem​. It will also instantiate serial-getty@​.service instances for virtualizer consoles, if execution in a virtualized environment is detected​. If execution in a container environment is detected, it will instead enable console-getty​.service for /dev/console, and container-getty@​.service instances for additional container pseudo TTYs as requested by the container manager (see Container Interface​^[1])​. This should ensure that the user is shown a login prompt at the right place, regardless of which environment the system is started in​. For example, it is sufficient to redirect the kernel console with a kernel command line argument such as console= to get both kernel messages and a getty prompt on a serial TTY​. See The kernel's command-line parameters​^[2] for more information on the console= kernel parameter​.

systemd-getty-generator implements systemd.generator(7)​.

Further information about configuration of gettys can be found in systemd for Administrators, Part XVI: Gettys on Serial Consoles (and Elsewhere)​^[3]​.

systemd-getty-generator understands the following kernel-command-line(7) parameters:

systemd​.getty_auto=

This kernel command line option may be used to control the execution mode of the generator​. Takes an optional boolean argument​. Since v258, this also takes comma-separated list of special values: "credential", "container", "console", and "builtin"​.

When "credential" is specified, the two credentials getty​.ttys​.serial and getty​.ttys​.container will be parsed​. See System Credentials section below for more details​.

When "container" is specified, console-getty​.service and container-getty@​.service will be enabled when the system is running in a container​. This option will be ignored when the system is not in a container​.

When "console" is specified, serial-getty@​.service for active kernel consoles will be enabled​. This option will be ignored when the system is running in a container​.

When "builtin" is specified, serial-getty@​.service for available virtualizer consoles will be enabled​. This option will be ignored when the system is running in a container​.

When yes, the above four options will be enabled​. When no, all options are disabled and no service will be enabled​. When the kernel command line option is specified without an argument, defaults to yes​. The generator is enabled by default, and a false value may be used to disable it​.

Added in version 250​.

$SYSTEMD_GETTY_AUTO

This environment variable may be used to control the execution mode of the generator​. Takes the same value as systemd​.getty_auto= kernel command line option​.

Added in version 250​.

getty​.auto

The system credential may be used to control the execution mode of the generator​. Takes the same value as systemd​.getty_auto= kernel command line option​.

Added in version 258​.

getty​.ttys​.serial,  getty​.ttys​.container

These system credentials may be used to spawn additional login prompts on selected TTYs​. The two credentials should contain a newline-separated list of TTY names to spawn instances of serial-getty@​.service (in case of getty​.ttys​.serial) and container-getty@​.service (in case of getty​.ttys​.container) on​. Any lines starting with a "#" will be ignored​.

Added in version 254​.

systemd(1), kernel-command-line(7), systemd.system-credentials(7), agetty(8)

1. Container
      Interface
   https://systemd.io/CONTAINER_INTERFACE
2. The kernel's command-line parameters
   https://docs.kernel.org/admin-guide/kernel-parameters.html
3. systemd for Administrators, Part XVI: Gettys on Serial Consoles (and Elsewhere)
   https://0pointer.de/blog/projects/serial-console.html