feat:[close #159] Systemd mount units

[taukakao]

Using systemd mount units instead of a mount script together with a systemd service has a couple of benefits:

• slightly faster boot since some mounts can be run in parallel
• it's a more standard way of doing things
• it's easier to manage more complex dependencies between mount points

The dependency between mounts with this implementation looks like this:

The reason we can't do this all in fstab is because you can't easily tell systemd to mount for example /home from /var/home after /var is mounted.

The question is: If we already use systemd mount units, it might be cleaner to put everything into mount units and not just the bind and overlay mounts. (The behavior would be identical since systemd just generates the mount units anyway from fstab)

Additionally, currently, the system will still try to boot even if a mount point fails, should this be changed so that systemd has to boot into recovery if a mount fails?

Also, if you want to test this, you can currently use this build: https://github.com/taukakao/ABRoot/releases/tag/systemdmount

Things that still need to be done:

• decide if we should move everything from fstab to mount units (no, not worth it)
• decide if the boot should fail on one failed mount point (no, the system can display an error in the future if it failed)
• remove workflow changes
• rebase and squash
• also reflect these changes in the installer

[matbme]

decide if the boot should fail on one failed mount point

In the future, we can create an "error" user that gets overwritten by the /etc mount. If the mount fails and the user still exists, we can have a custom shell showing an error.

[mirkobrombin]

Ping #159 (for tracking purposes)

[matbme]

Implementation looks good to me, but it will also require a change in vanilla-installer to use Systemd mount units. I'll work on that as soon as I can and we can then merge both PRs at the same time

[mirkobrombin]

Implementation looks good to me, but it will also require a change in vanilla-installer to use Systemd mount units. I'll work on that as soon as I can and we can then merge both PRs at the same time

Can you make an issue for that which locks this?

[taukakao]

In the future, we can create an "error" user

That sounds like a good idea 👍

I'll work on that as soon as I can

I can probably also do the installer part. I only wanted to wait if this is even wanted, which it seems to be.

[taukakao]

This is now ready together with Vanilla-OS/vanilla-installer#311