Systemd: how to get into rescue mode

[Tom H]

On Fri, Jan 10, 2020 at 10:32 PM Volker Wysk <post at volker-wysk.de> wrote:
> Am Freitag, den 10.01.2020, 21:39 +0100 schrieb Tom H:
>> On Sun, Jan 5, 2020 at 10:50 AM Volker Wysk <post at volker-wysk.de>
>> wrote:
>>>
>>> I do this:
>>>
>>> systemctl isolate rescue.target
>>>
>>> Then everything is closed, and I get to a virtual console. There,
>>> the root password is queried.
>>>
>>> Alas, there is no reaction whatsoever. I can enter the password,
>>> but nothing happens. Same for ctrl-d. The other virtual consoles are
>>> dead. Alt-ctrl-del isn't recognized, too. I need to do a hard reset.
>>>
>>> The systemctl command, above, is mentioned in an article in the
>>> German linux magazine LinuxUser.
>>
>> How about switching to a console, running "systemctl stop your_DM"
>> (or "systemctl isolate multi-user.target"), and then "systemctl
>> isolate rescue.target"?
>
> This works!

Yes! Good to know.

> I've tried it with "systemctl isolate multi-user.target", and then
> "systemctl isolate rescue.target". But, when you afterwards type
> ctrl-D or "exit", it stands still with the ubuntu symbol, with the
> dots under the "ubuntu" lettering. It's the same with typing
> "systemctl isolate default.target" instead. So you have to do a reboot.

I would've expected "systemctl isolate default.target" to have worked.
What do you see when you press "Esc" when the Ubuntu logo's displayed?
(I think that this is the way to see the boot messages, but I don't
use "quiet" at the cmdline so I'm not sure).