Posted on by richay

Proxmox Unprivelliged LXC with shared Intel ARC GPU for Plex or Jellyfin transcoding

This is to create Plex and/or Jellyfin using docker within an Unprivilleged LXC container using Proxmox with access to the LXC’s host Intel ARC GPU.

I’m using Debian Trixie LXC for this example. This assumes you have:

Check the render device group on the host

ls -l /dev/dri/render*


Example output:

crw-rw---- 1 root render 226, 128 Nov 16 21:02 /dev/dri/renderD128
crw-rw---- 1 root render 226, 129 Nov 16 21:02 /dev/dri/renderD129


This is for the iGPU and the ARC GPU, the ARC GPU is renderD129. Both are part of the device GROUP 226 this will be needed later on.

Find the GID of the render group on the host – HOST_GID

getent group render


Example output:

render:x:993:


We also need the render group of the LXC – LXC_GID

getent group render


Example output:

render:x:105:



On the proxmox host, edit the config for the lxc

nano /etc/pve/lxc/<CTID>.conf


Add these lines in, remembering:
GROUP: 226
LXC_GID: 105
HOST_GID: 993
SUBUID_START: 100000 (constant)
BASE_RANGE: 65536 (constant)

lxc.cgroup2.devices.allow: c 226:0 rwm
lxc.cgroup2.devices.allow: c 226:128 rwm
lxc.mount.entry: /dev/dri/renderD128 dev/dri/renderD128 none bind,optional,create=file
lxc.cgroup2.devices.allow: c 226:129 rwm
lxc.mount.entry: /dev/dri/renderD129 dev/dri/renderD129 none bind,optional,create=file
lxc.idmap: u 0 100000 105
lxc.idmap: g 0 100000 105
lxc.idmap: u 105 993 1
lxc.idmap: g 105 993 1
lxc.idmap: u 106 100106 65430
lxc.idmap: g 106 100106 65430


This is to share both the iGPU and ARC GPU with 226 being the group.
The idmaps are rather complicated but you should be fine if you follow the rules 

lxc.idmap: u 0 SUBUID_START BASE_RANGE = lxc.idmap: u 0 100000 105
lxc.idmap: g 0 SUBUID_START BASE_RANGE = lxc.idmap: g 0 100000 105

lxc.idmap: u LXC_GID HOST_GID 1 = lxc.idmap: u 105 993 1
lxc.idmap: g LXC_GID HOST_GID 1 = lxc.idmap: g 105 993 1

lxc.idmap: u (LXC_GID+1) (SUBUID_START + LXC_GID + 1) (BASE_RANGE - (LXC_GID+1)) = lxc.idmap: u 106 100106 65430
lxc.idmap: g (LXC_GID+1) (SUBUID_START + LXC_GID + 1) (BASE_RANGE - (LXC_GID+1)) = lxc.idmap: g 106 100106 65430


Save and exit the config.

We need to add the HOST_GID to the proxmox host subuid and subgid files

nano /etc/subuid


This should be as follows, then save and close

root:100000:65536
root:993:1


The same for the subgid

nano /etc/subgid
root:100000:65536
root:993:1


Restart the LXC container so the new config is loaded. Nearly there..

Docker Compose

For both Plex and Jellyfin the ARC GPU needs to be passed through into the container, add these lines into the docker compose file 

    devices:
      - /dev/dri:/dev/dri

Plex

For Plex, go to Settings, Transcoder then scroll down to Hardware transcoding device your ARC should be there. Mine shows Intel DG2 [Arc A310]. If it’s not here, double check the idmaps in the LXC config from the proxmox host

Test the transcoding by playing any video, then in the Play Settings change the quality to something lower, then go to Activity, Dashboard and see if its transcoding with a hardware (hw) tag

NOTE: Hardware transcoding does require a subscription.
 

Jellyfin

For Jellyfin, top left 3 bars, Adminstration, Dashboard
Then Playback, Transcoding
Under Hardware Acceleration select Intel Quicksync (QSV)
With QSC Device enter /dev/dri/renderD129 for your ARC GPU
(or /dev/dri/renderD128 if you dont have iGPU)

To test play a video, go to the Play Settings, lower the quality, then click Playback Info
Look through the info for Play method Transcoding.
When Jellyfin transcoding is incorrectly setup videos wont play at all, check the idmaps in the LXC config from the proxmox host

2 Replies to “Proxmox Unprivelliged LXC with shared Intel ARC GPU for Plex or Jellyfin transcoding”

Leave a Reply

Your email address will not be published. Required fields are marked *