Docker container user permission settings for SMB-mounted directory

To ensure the Docker container can read and write to an SMB-mounted directory, you need to properly set permissions on both:

1. The SMB mount on the host system.
2. The user inside the Docker container (usually by matching uid and gid).

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✅ Step-by-Step: Set Correct Permissions

🧱 1. Mount the SMB Share with Correct UID/GID

Use mount -t cifs with uid and gid options to set file ownership on the host.

Example:

sudo mount -t cifs //192.168.1.100/shared /mnt/smb \
  -o username=myuser,password=mypass,uid=1000,gid=1000,vers=3.0

• uid=1000 — maps all files in the mount to user ID 1000
• gid=1000 — maps group to group ID 1000
• Check your Docker container user ID with:

docker exec -it mycontainer id

Example output:

uid=1000(node) gid=1000(node)

If your container uses UID 100, set uid=100 in the mount.

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🐳 2. Match UID/GID Inside Docker

If your Docker image uses a specific user, you can:

• Use --user in the docker run command:

docker run --user 1000:1000 -v /mnt/smb:/data/smb-share my-n8n

• Or check the Dockerfile or entrypoint to see which user is used (some use node, n8n, or www-data).

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🛠 3. Adjust Mount Permissions (Optional)

If needed, you can also change permissions on the mount directory:

sudo chmod -R 770 /mnt/smb
sudo chown -R 1000:1000 /mnt/smb

But this only affects the local mount point; actual permissions are controlled by SMB share settings on the remote server.

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✅ Summary

Task	How to Do It
Map files to correct UID/GID	Use uid=... and gid=... in mount -t cifs
Use correct container user	Use --user UID:GID in docker run, or configure user in Dockerfile
Make sure mount is writable	Verify permissions on SMB server, or use chmod/chown on mount path