Linux

Permissions helper (UID/GID)

Convert UID and GID between container and host and get the correct chown or idmap command for Docker and LXC.

Where does your program run?

UID in the container

GID in the container

Folder on the host (Proxmox or computer)

Path in the container (optional)

Current owner UID on the host

Current owner GID on the host

UID shift (offset)

Container ID (for the idmap)

What does this mean?

Files have an owner with a number: a UID (user) and a GID (group). An unprivileged LXC container in Proxmox adds its numbers to 100000 on the host. A program running in the container as user 1000 is therefore user 101000 on the host. If your folder on the host has a different owner, you will get permission denied.

Two solutions: make the host folder owned by the converted number (simple), or map one UID directly to the host in the container configuration (idmap, cleaner if you share the same folder with multiple containers). Docker on a regular computer does not add: there UID 1000 in the container is simply UID 1000 on the host.

Did you not choose the offset of 100000 yourself? Then this is the default for Proxmox. When in doubt, check /etc/subuid on the host. Everything happens in your browser. Make a backup or snapshot before you change permissions with -R over a large folder.