Cgroup changes impacting Docker HW access

Plex Media Server Desktops & Laptops
1

I have the same issue when running plex in a docker container on a synology box.

failed to open /data/jenkins/pms-deps-universal-v2/BUILD_TAG/linux-ubuntu-x86_64/output/pms-depends-linux-ubuntu-x86_64-release-79dcc0f/lib/dri/hybrid_drv_video.so
Failed to wrapper hybrid_drv_video.so

If I deactivate hardware acceleration errors go away but video is not usable as it skips every 1 second.

2

That is a Docker problem. Unfortunately can’t help you here. Please redirect to server-docker

Be advised. HW transcoding, in Docker, on Synology is asking to get oneself slapped upside the head. :joy:
Docker doesn’t support automatic passthrough.

I provide automatic HW mapping in the native Synology installer.

3

@ChuckPa Running docker in privileged mode should give all the permissions needed along with a dev snapshot so I’m not sure why you’re saying this asks for trouble - It’s actually a much cleaner way to maintain a component on Synology.
As well, I’m using the official plex docker images so I’m not sure why this is not the right place to point out these issues.

4

No… Running docker in privileged mode won’t. give you access to hardware transcoding automatically.

You are running a chroot() filesystem (how containers work)
As such, the root of the container is some directory well below and away from /dev/dri

5

That is partially correct. The privileged deactivates all the limitations enforced by the device cgroup controller - basically that is an . This along with either full dev bind mount or specific device bind mount would give full access to host’s dri.

6

Have you considered the normal procedure of adding -v /dev/dri:/dev/dri to your mapping and being done with it?

7

@al3phan

I moved this thread here. It should not be part of a mainstream (host) linux server issue.
This is confined to within the scope of the container and the s6 init exec

8

Yes. The container has that mapping available.

        "Devices": [
            {
                "PathOnHost": "/dev/dri",
                "PathInContainer": "/dev/dri",
                "CgroupPermissions": "rwm"
            }
        ],

As well, the host has full permissions on these devices.

9

Just for laughs, which group owns /dev/dri and what group is user plex assigned/mapped?

Normal Linux adds group video and everything falls perfectly into place without the need of privileged mode.

10

It has 777 on all the dri devices:
drwxrwxrwx 2 root root 100 Jan 4 02:37 .
drwxr-xr-x 13 root root 18740 Jan 4 02:39 …
crwxrwxrwx 1 root root 226, 0 Jan 4 02:37 card0
crwxrwxrwx 1 root root 226, 64 Jan 4 02:37 controlD64
crwxrwxrwx 1 root root 226, 128 Jan 4 02:37 renderD128

11

That being fact, I don’t know why your docker is having this problem.

I am not a docker person.

I am tagging this as server-docker for the docker team to see.
Please leave it so tagged.

12

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