Run top instead of getty

Question

By default, systemd auto-launches getty on each VT except VT7. What I would like is for systemd to launch top on VT6 instead of getty. Any idea how I configure it to do that?

What evidence do you have that systemd auto-launches, why do you think this would be configurable or that you'd be able to change this into an interactive program?. And what exactly are you trying to do? — rocky, Jun 23 '15 at 09:19
Consider, for example, this: http://unix.stackexchange.com/questions/56531/how-to-get-fewer-ttys-with-systemd which explains how to adjust the number of VTs which auto-launch `getty`. — MathematicalOrchid, Jun 23 '15 at 09:33

score 4 · Accepted Answer · answered Jun 23 '15 at 12:31

4

I don't think you can do it on tty6 because:

tty6 is especially reserved for auto-spawned gettys and unavailable to other subsystems such as X[3]. This is done in order to ensure that there's always a way to get a text login, even if due to fast user switching X took possession of more than 5 VTs.

For more info you can check here.

But you can try this on tty5 for example. You can create following service (testo.service or whatever you decide) in /lib/systemd/system/ on most distributions but in openSUSE I think it is /usr/lib/systemd/system:

[Unit]
Description=top on tty5

[Service]
Type=simple
ExecStart=/usr/bin/top
ExecStop=/bin/kill -HUP ${MAINPID}
StandardInput=tty
StandardOutput=tty
TTYPath=/dev/tty5
Restart=always
RestartSec=2

[Install]
WantedBy=getty.target

And then:

systemctl enable testo.service

answered Jun 23 '15 at 12:31

taliezin

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Worked perfectly first time. Well done! – MathematicalOrchid Jun 23 '15 at 13:41
1

You've missed the part where you tell `logind` not to attempt to start `[email protected]` or you tell systemd that this is (an alias for) `[email protected]`. Also note that if all that one wants to do is change `ExecStart` for one specific instance of the template unit, there's another way to do that. – JdeBP Jun 23 '15 at 21:07
@JdeBP i've tested on debian an it worked as expected without additional configuration. Could you elaborate on this so we can improve this answer? – taliezin Jun 23 '15 at 21:14
@JdeBP thanks, I will read and try to edit it tomorrow. – taliezin Jun 23 '15 at 21:36
https://wiki.archlinux.org/index.php/Automatic_login_to_virtual_console for the second part. `logind` tries to check to ensure that the virtual terminal isn't already in use, but there's a very small window where this can potentially race with another service, depending from exactly how one activates things. But the alias is *definitely* necessary if one has, say, explicitly instantiated a `[email protected]` or followed something like https://fedoraproject.org/wiki/Systemd#How_do_I_set_automatic_login_on_a_virtual_console_terminal.3F . – JdeBP Jun 23 '15 at 21:42
@JdeBP The systemd documentation says it only tries to auto-launch `getty` if the terminal is otherwise unused. Presumably starting `top` prevents the auto-launch of `getty`. Works on my OpenSUSE box. – MathematicalOrchid Jun 24 '15 at 08:07

score 1 · Answer 2 · answered Jun 23 '15 at 09:53

What he is trying to do is: have a "top" always available on vt6. Seems like a reasonable goal to me.

The configuration vor the login gettys on the vt's are in /etc/systemd/logind.conf

Here you can restrict systemd on the usage of login-vt's.

What i don't know at the moment is, how the "inittab" functionallity is handled by current distros. "inittab" is where you would have put such a process ...

Maybe this helps? Best regards, gerhard

Run top instead of getty

2 Answers2