On a RHEL8-based virtual machine running systemd 239, I have the following bind-mount setup:
- a filesystem (identified via UUID) mounted to a "source" mount-point (
/path/to/sourcemnt) - multiple sub-directories on that "source" mount-point:
/path/to/sourcemnt/dirA /path/to/sourcemnt/dirB /path/to/sourcemnt/dirC - bind-mounts for each sub-directory to "target" mount-points
The fstab looks like this:
# auto-generated entries for 'sourcemnt' UUID=<...> /path/to/sourcemnt ext4 defaults 1 2 # manually added entries for bind mounts /path/to/sourcemnt/dirA /path/to/targetmnt/dirA none bind,x-systemd.requires=/path/to/sourcemnt 0 0 /path/to/sourcemnt/dirB /path/to/targetmnt/dirB none bind,x-systemd.requires=/path/to/sourcemnt 0 0 /path/to/sourcemnt/dirC /path/to/targetmnt/dirC none bind,x-systemd.requires=/path/to/sourcemnt 0 0 The Problem
Not all of the bind-mounts are automatically mounted during boot. This can be seen from the ownership/permissions of the mount-points as well as output of findmnt and mountpoint commands.
- The
journalctloutput doesn't contain error messages trying to mount the "failed" bind-mounts, they are simply never mentioned. Only the successfully mounted bind-mounts are mentioned in the usual way:<Date> <Hostname> systemd[1]: Mounting /path/to/sourcemnt... ... <Date> <Hostname> systemd[1]: Mounted /path/to/sourcemnt. <Date> <Hostname> systemd[1]: Mounting /path/to/targetmnt/dirB... ... <Date> <Hostname> systemd[1]: Mounted /path/to/targetmnt/dirB. - Manually mounting them (as
root) works. - The number of "failing" bind-mounts is not consistent on re-boot. Sometimes only one is missing, sometimes two, but at least one is always successfully mounted.
- Changing the order in which the bind-mounts are specified in the
fstabdoesn't change which of them are mounted and which are not. - It seems that the one lexicographically in the middle of the sort-order (
dirB) is always there,dirAsometimes anddirConly after a hard restart (if at all) - but I didn't try often enough to say for sure. - The same setup still worked as of RHEL7
This looks like a timing problem/race condition, but how can I ensure that all bind-mounts are present? I even tried to "cascade" the mount-requirements as in
/path/to/sourcemnt/dirA /path/to/targetmnt/dirA none bind,x-systemd.requires=/path/to/sourcemnt 0 0 /path/to/sourcemnt/dirB /path/to/targetmnt/dirB none bind,x-systemd.requires=/path/to/targetmnt/dirA 0 0 /path/to/sourcemnt/dirC /path/to/targetmnt/dirC none bind,x-systemd.requires=/path/to/targetmnt/dirB 0 0 but that also didn't help (that said, why should it in the first place?).
