[PATCH container/manager v2 0/7] implement per-mountpoint uid/gid mapping

Filip Schauer
2026-03-30T14:10:37Z

Add support for configuring UID/GID mappings on individual container
mount points without affecting the global container mapping.

A new "idmap" mount point option accepts semicolon-separated mappings:
```
idmap=type:ct:host:len;type:ct:host:len;...
```

type: can be either 'u' or 'g'
ct: ID as seen inside the container
host: corresponding ID on the host
len: number of consecutive IDs to map

Unmapped ranges inherit the container's ID mapping.

Example to pass through the host UID & GID 1005:
```
mp0: /mnt/data,mp=/data,idmap=u:1005:1005:1;g:1005:1005:1
```

To identity-map the entire range of ids, "passthrough" can be used:
```
idmap=passthrough
```

Mount point idmapping only works for unprivileged containers. Privileged
containers are unaffected.

Build/Bump order:
* pve-container
* pve-manager

Changes since v1:
* Include $msg in error message in sync_send/sync_recv
* Switch idmap from space-separated to semicolon-separated
* Improve documentation of idmap option
* Add 'idmap=passthrough'
* Cache user namespace file descriptors in memory at container startup
to avoid overhead of re-creating duplicates

pve-container:

Filip Schauer (5):
namespaces: relax prototype of run_in_userns
namespaces: refactor run_in_userns
d/control: update versioned dependency for libpve-common-perl
namespaces: add helper to create user namespace from idmap
implement per-mountpoint uid/gid mapping

debian/control | 2 +-
src/PVE/LXC.pm | 96 +++++++++++++++++++++++++++++++++++++--
src/PVE/LXC/Config.pm | 39 ++++++++++++++++
src/PVE/LXC/Namespaces.pm | 63 ++++++++++++++++++++-----
src/lxc-pve-prestart-hook | 23 ++++++++++
5 files changed, 206 insertions(+), 17 deletions(-)

pve-manager:

Filip Schauer (2):
ui: lxc/MPEdit: remove duplicate "mp" assignment
ui: lxc/MPEdit: add "idmap" option

www/manager6/lxc/MPEdit.js | 213 ++++++++++++++++++++++++++++++++++++-
1 file changed, 212 insertions(+), 1 deletion(-)

Summary over all repositories:
6 files changed, 418 insertions(+), 18 deletions(-)

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