Re: Issue with PostgreSQL 18.0 Docker image volume mount (/var/lib/postgresql/data symlink)

On Fri, Sep 26, 2025, 12:05 Pavel Hushcha <paul(dot)fastest(at)gmail(dot)com> wrote:

> Hello,
>
> I’ve encountered a problem when trying to upgrade from the `postgres:17.6`
> Docker image to `postgres:18.0`.
>
> With PostgreSQL 17.6, the volume mapping worked fine:
>
> ```yaml
> volumes:
> -
> /volumeUSB1/usbshare1-6/configs/postgresql/data:/var/lib/postgresql/data/
> ```
>
> However, with `postgres:18.0`, the container fails to start with the
> following error:
>
> ```
> Error response from daemon: failed to create task for container: failed to
> create shim task:
> OCI runtime create failed: runc create failed: unable to start container
> process:
> error during container init: error mounting
> "/volumeUSB1/usbshare1-6/configs/postgresql/data"
> to rootfs at "/var/lib/postgresql/data": change mount propagation through
> procfd:
> open o_path procfd: open
> /volumeUSB1/usbshare1-6/docker/btrfs/subvolumes/362b5618ea6ff38caa0671921e892066b3ad705e39270f938aac396f7401781e/var/lib/postgresql/data:
>
> no such file or directory: unknown
> ```
>
> I noticed that the difference is in the Docker image itself:
>
> * In 17.6, `/var/lib/postgresql/data` is a real directory.
> * In 18.0, `/var/lib/postgresql/data` is a symlink to `.`.
>
>
> This change seems to break bind mounts on some storage backends (in my
> case, Btrfs on a Synology NAS).
>
> Could you confirm if this symlink change in the official PostgreSQL 18.0
> Docker image is intentional?
> And if so, is there a recommended way to mount external volumes for
> `PGDATA` now?
>

Hello!

Those docker containers are not provided by the PostgreSQL project. You
need to contact the docker team for questions about those.

/Magnus

>