Debian Buster terminal autologin

Question

I'm repacking a Debian Buster Live ISO. I first unpack the filesystem.squashfs, then chroot in the unsquashed system, make my changes.

I want my ISO to autologin (terminal). I've followed this techniques, but I failed because I get the error:

System has not been booted with systemd as init system (PID 1). Can't operate.
Failed to connect to bus: Host is down

So I can't use systemctl, which throws this error.

The answers I've found here to bypass the error say to use service instead of systemctl, which doesn't apply in my case.

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Is poosible to autologin using another technique?

Is possible to get systemctl functioning inside a chroot, so I can apply above technique?

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Tentative answer:

I created the file getty@tty.service under /lib/systemd/system and made a sysmlink in /etc/systemd/system/multi-user.target.wants/. The contents of the file.

[Service]
ExecStart=
ExecStart=-/sbin/agetty --autologin root --noclear %I 38400 linux

This got me into autologin. I'll wait for insight before answer my own question.

Answer 1

Note: This may be or may be not related to your problem, but the problem I explain here will lead to the same error messages you have shown due to a missing symlink.

I am not an expert, but in Debian 10 (Buster) the default init system is systemd which means /sbin/init (/usr/sbin/init) will link to systemd.

Unfortunately there is a bug I noticed when running multiple KVM guests which causes that the symlink /sbin/init which links to /lib/systemd/systemd is removed. I don't know the reason for that, however, I suspect that org.freedesktop.systemd1 (I absolutely don't know what that is) could be the reason.

Correct Symlink

The correct output would be:

root@vpstest:~# ls -la /sbin/init
lrwxrwxrwx 1 root root 20 Jan 29 19:07 /sbin/init -> /lib/systemd/systemd

Missing Symlink

If it shows that, there may be something wrong:

root@vps1:~# ls -la /sbin/init
-rwxr-xr-x 1 root root 53016 Feb 14  2019 /sbin/init

Fix

To fix that, I just remove that file and rebuild the symbolic link:

rm /sbin/init && ln -s /lib/systemd/systemd /sbin/init

When you're using virsh you need to destroy and then start the guest:

virsh destroy vps1 && virsh start vps1