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Proxmox LXC idmap → Idmapped Mount Converter

Paste your old lxc.idmap block and get the Proxmox 8.1+ idmapped mount config line plus cleanup commands — all ready to copy.

Paste the lxc.idmap lines from your container config, enter the host path, LXC path, and mount point index. The tool detects which UID/GID rows are passthrough mappings, generates the replacement mpX: line for /etc/pve/lxc/<CTID>.conf, and shows the cleanup commands to remove the old lxc.idmap block.

Requires Proxmox 8.1 or newer (kernel 6.x). The backing filesystem must support idmapped mounts: ZFS, ext4, and XFS all work. Older NFS or CIFS exports may not.

Old config

Paste the lxc.idmap lines from your <CTID>.conf. One line per row.

Absolute path to the directory on the Proxmox host, e.g. /mnt/media.

Absolute path where the data should appear inside the container, e.g. /media.

The mpX index in the container config, e.g. 0 for mp0.

Used only in the cleanup commands. Leave blank to use a generic <CTID> placeholder.

Detected passthrough IDs 
No passthrough rows detected — paste your lxc.idmap block above.
New <CTID>.conf line 
Enter a host path and LXC path to generate the config line.
Cleanup commands 
Fill in the fields above to generate cleanup commands.

What this tool does

Legacy LXC containers on Proxmox used a lxc.idmap block in <CTID>.conf plus matching entries in /etc/subuid and /etc/subgid to remap container UIDs/GIDs to host UIDs/GIDs. A typical setup for passing through a single host user (UID 1000) looks like this:

lxc.idmap: u 0 100000 1000
lxc.idmap: g 0 100000 1000
lxc.idmap: u 1000 1000 1
lxc.idmap: g 1000 1000 1
lxc.idmap: u 1001 101001 64535
lxc.idmap: g 1001 101001 64535

The tool reads those lines, picks out the passthrough rows (containerId === hostId), and builds the idmapped mount line that replaces them — mp0: /mnt/media,mp=/media,idmapped=1. It also shows the sed command to strip the old lxc.idmap lines and a reminder to clean up the matching subuid/subgid entries.

Mastering UID/GID Mapping in Proxmox LXC Containers

Background on UID/GID mapping, default offset layouts, and when traditional lxc.idmap is still the right approach.

Read the full guide