[PVE-User] LXC: Directory mount not writeable

Arjen leesteken at protonmail.ch
Wed Jan 27 15:47:02 CET 2021

> Hello,
> created a directory mount using
> pct set 300 -mp0 <host dir>,mp=<vm mountpoint>,ro=0

Is this an unprivileged container?

> But in the lxc vm this directory is not writeable. A test with
> touch <vm mountpoint>/z
> fails. Omitting the "ro"-option does not change this.

This sounds like a user-permission-issue and not a read-only/not-writable problem. Unless the directory on the host is mounted (from another device) as read-only.

> If i change in 300.conf the line from
> mp0: <host dir>,mp=<vm mountpoint>,ro=0
> to
> mp0: <host dir>,mp=<vm mountpoint>,rw=1
> the touch command works inside the container.
> But then the GUI shows an error:
> mp0: invalid format - format error mp0.rw: property is not defined in schema and the
> schema does not allow additional properties

rw does not exists. ro=0 is correct.

> Is this (mountpoint not being writeable) a bug ?
> If yes should i write a bug report ?

No, this is probably a user/owner permission issue. Please check that the user that you use has permissions to write in the mounted directory. Please note that the user-ID of a unprivileged container is offset by 100000. Maybe you can show the user-ID, and the owner-ID and group-ID of the directory, and the rwx-permissions of the directory (all from both inside the container and from the Proxmox host).

> Updated the proxmox server today from the no-subscription repository. The web GUI is
> at version 6.3-3.

This looks to be up to date.

> regards
> Petric
kind regards

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