Thread

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

   Pavel Hushcha <paul.fastest@gmail.com> — 2025-09-26T05:53:09Z

   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?
   
   Thanks,
   Pavel Hushcha
   
   
   
   
   

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

   Magnus Hagander <magnus@hagander.net> — 2025-09-26T09:14:08Z

   On Fri, Sep 26, 2025, 12:05 Pavel Hushcha <paul.fastest@gmail.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
   
   >