Gentoo Linux VM: Parallels Tools causes repeated "fstab has been modified" warnings during emerge

[Leonchik1976]

Hello, i know Gentoo Linux not directly supported, but hopefully my problem is more general to linux, than related to gentoo.
I am running Gentoo Linux in Parallels Desktop on a Mac Studio with Apple Silicon. Parallels Desktop and Parallels Tools are both up to date. Parallels Tools are installed in the guest and working.
Before installing Parallels Tools, Portage/emerge output was clean. After installing Parallels Tools, every emerge command started printing repeated warnings like this:
mount: (hint) your fstab has been modified, but systemd still uses
the old version; use 'systemctl daemon-reload' to reload.

As far as I can tell, /etc/fstab itself is not actually edited at any time, and its content does not appear to change. The packages still build normally, so this does not seem to break the system, but the repeated warning is noisy and confusing.

I also noticed that running:
timedatectl set-ntp true
systemctl daemon-reload

temporarily suppresses the warning, but it later comes back. This makes me suspect there may be an interaction between Parallels Tools and linux time synchronization (systemd).
I am looking for the correct supported way to stop this warning without disabling Parallels Tools entirely.
Has anyone else seen this with a Linux guest, especially Gentoo or another systemd-based distribution? Is there a recommended Parallels Tools setting or workaround for this?

 

[RyanM45]

I am running Gentoo using OpenRC instead of the systemd but I doubt that will be a critical issue here. If you have the Parallels Guest tools installed (which I would recommend) then it will give you extra functionality like being able to see the contents of folders shared using Parallels. One other piece of functionality is the Parallels time sync daemon which runs in the background and attempts to keep your VM system time in sync with your Mac's system time.

First I would double-check you aren't having time kind of weird timezone issue going on. You can check that using the shell command 'date' and 'date -u'. At least make sure the system clock on your VM is correct based on the time and timezones reported by those commands.

Assuming that's OK, then the other potential conflict is running NTP on your VM. You need to decide whether you want the Parallels time sync daemon running or NTP. But I wouldn't recommend running both at the same time. They will each try to control the system clock and the clock will warp back and forth which is probably what you're seeing.

If you're running your VM only occasionally or your are running it on a laptop then Parallels time sync is probably what you want. Don't run NTP in your VM. If the VM s up all the time and never turns off then you may not want the Parallels time sync running. I find that my Macs aren't always right on with time sync. NTP would probably do better.

I haven't seen a supported way to keep the Parallels time sync daemon from running. So you'll need to hack something together. One way is to let the Parallels guest tools install, find the 'prltimesync' executable and mark it non-executable so it won't run. But you'll have to do that every time you upgrade your Parallels version.

My solution on one VM where I wanted NTP was to run a startup script which ran after the Parallels tools startup script. That script issues a 'killall prltimesync' command to kill the Parallels time sync daemon. Then let NTP keep in time in sync.