Comment by cyberax
1 day ago
> How do we determine that a specific instance of a filesystem mount is "remote", or even requires a "network"?
Like systemd authors do! Hard-code the list of them in the kernel, including support for fuse and sshfs. Everything else is pure blasphemy and should be avoided.
Me? I'd have an explicit setting in the mount unit file, with defaults inferred from the device type. I would also make sure to not just randomly add landmines, like systemd-update-done.service. It has an unusual dependency requirements, it runs before the network filesystems but after the local filesystems.
I bet you didn't know about it? It's a service that runs _once_ after a system update. So the effect is that your system _sometimes_ fails to boot.
> systemd has .mount units which are way more configurable than /etc/fstab lines
It's literally the inverse. As in, /etc/fstab has _more_ options than native mount units. No, I'm not joking.
Look at this man page: https://www.freedesktop.org/software/systemd/man/latest/syst... The options with "x-systemd." prefix are available for fstab.
Look for the string: "Note that this option can only be used in /etc/fstab, and will be ignored when part of the Options= setting in a unit file."
Sounds like your admin, distro, or the systemd team could pay some attention to systemd-update-done.service
The "can only be used in /etc/fstab" systemd settings are essentially workarounds to do those things via fstab (and workaround fstab related issues) rather than depend on other systemd facilities (c.f. systemd-gpt-auto-generator). From a "what can you do in /etc/fstab without knowing systemd is working behind the scenes" point of view, then yes, systemd units are vastly more configurable.
This service is the standard part of systemd. And my distro is a bog-standard Fedora, with only iSCSI as a complication.
Are you surprised that such a service exists? I certainly was. And doubly so because it has unusual dependency requirements that can easily lead to deadlocks. And yes, this is known, there are open issues, and they are ignored.
> From a "what can you do in /etc/fstab without knowing systemd is working behind the scenes" point of view, then yes, systemd units are vastly more configurable.
No, they are not. In my case, I had to use fstab to be able to specify a retry policy for mount units (SMB shares) because it's intentionally not exposed.
And yes, there's a bug: https://github.com/systemd/systemd/issues/4468 with the expected GTFO resolution: https://github.com/systemd/systemd/issues/4468#issuecomment-...
So there's literally functionality that has been requested by people and it's available only through fstab.