Files
Peter Whittaker 345b9b0295 Update rootfs.md: Fix formatting and wording of idmap option
The newly introduced `idmap` section of rootfs lacked a header
(comparable to Overlay Rootfs Mounts), had odd formatting, and
wording that differed from other instances of idmap, e.g., the
one in the --volume section. This commits addresses those issues.

Signed-off-by: Peter Whittaker <PeterWhittaker@SphyrnaSecurity.com>
2023-08-14 09:21:24 -04:00

1.5 KiB

####> This option file is used in: ####> podman create, run ####> If file is edited, make sure the changes ####> are applicable to all of those.

--rootfs

If specified, the first argument refers to an exploded container on the file system.

This is useful to run a container without requiring any image management, the rootfs of the container is assumed to be managed externally.

Overlay Rootfs Mounts

The :O flag tells Podman to mount the directory from the rootfs path as storage using the overlay file system. The container processes can modify content within the mount point which is stored in the container storage in a separate directory. In overlay terms, the source directory is the lower, and the container storage directory is the upper. Modifications to the mount point are destroyed when the container finishes executing, similar to a tmpfs mount point being unmounted.

Note: On SELinux systems, the rootfs needs the correct label, which is by default unconfined_u:object_r:container_file_t:s0.

idmap

If idmap is specified, create an idmapped mount to the target user namespace in the container. The idmap option supports a custom mapping that can be different than the user namespace used by the container. The mapping can be specified after the idmap option like: idmap=uids=0-1-10#10-11-10;gids=0-100-10. For each triplet, the first value is the start of the backing file system IDs that are mapped to the second value on the host. The length of this mapping is given in the third value. Multiple ranges are separated with #.