Can't to forward a sound card to container LXC.

[Yashalta]

I'm trying to forward a sound card to container LXC and get error.

mknod: snd/controlC0: Operation not permitted
mknod: snd/controlC2: Operation not permitted
mknod: snd/controlC1: Operation not permitted
mknod: snd/hwC2D0: Operation not permitted
mknod: snd/pcmC0D0p: Operation not permitted
mknod: snd/pcmC0D0c: Operation not permitted
mknod: snd/pcmC0D1p: Operation not permitted
mknod: snd/pcmC2D3p: Operation not permitted
mknod: snd/pcmC1D0p: Operation not permitted
mknod: snd/timer: Operation not permitted
mknod: snd/seq: Operation not permitted

if i right understand "Unprivileged containers are not allowed to create device nodes."!
Then how do I organize sound support in a container LXC?

"Debian 10" is installed in the container.

 

[oguz]

hi,

I'm trying to forward a sound card to container LXC and get error.

what's the process you're following to forward the card? what changes have you made?

if i right understand "Unprivileged containers are not allowed to create device nodes."!
Then how do I organize sound support in a container LXC?

if it's necessary to create device nodes, then you can use a privileged CT or just a VM with pci passthrough

 

[Yashalta]

hi,

what's the process you're following to forward the card? what changes have you made?
...

Thanks for answer!
I do according to this instruction https://forum.proxmox.com/threads/forward-alsa-audio-to-lxc-container.45310/#post-215942
After this instruction, appear a sound devices in the LXC container!

root@Sound:~# arecord -l
**** List of CAPTURE Hardware Devices ****
card 0: Dummy [Dummy], device 0: Dummy PCM [Dummy PCM]
  Subdevices: 8/8
  Subdevice #0: subdevice #0
  Subdevice #1: subdevice #1
  Subdevice #2: subdevice #2
  Subdevice #3: subdevice #3
  Subdevice #4: subdevice #4
  Subdevice #5: subdevice #5
  Subdevice #6: subdevice #6
  Subdevice #7: subdevice #7
card 1: NVidia [HDA NVidia], device 0: CX20561 Analog [CX20561 Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
root@Sound:~#

And started to work an alsamixer!

But, there is no sound from the LXC container!

...

if it's necessary to create device nodes, then you can use a privileged CT or just a VM with pci passthrough

How to make a privileged LXC container?
Can you give more details about it!

PS - And even no sound in the host, where is installed Proxmox itself! I tried to run some files for testing, files like .mp3, .wav.

 

[oguz]

hi,

PS - And even no sound in the host, where is installed Proxmox itself! I tried to run some files for testing, files like .mp3, .wav.

that seems suspicious. first make sure you have sound working on the host

How to make a privileged LXC container?
Can you give more details about it!

backup the container, and then restore it. while restoring it, deactivate the "unprivileged" setting

 

[Yashalta]

hi,
that seems suspicious. first make sure you have sound working on the host

Done!
Everything works fine on the host .mp3 and so on!
But, if I login by ssh to container by user root and run command alsamixer everything is looked fine! I can see and select any sound card from the list available! But user root cannot run pulseaudio! And and therefore it can't listen .mp3 files!
Ok, I created a user "sound", logged by user "sound" and run command alsamixer.
As a result, I have an error:

sound@player:~$ alsamixer
Failed to load cookie file from cookie: Permission denied
Failed to load cookie file from cookie: Permission denied
ALSA lib pulse.c:243:(pulse_connect) PulseAudio: Unable to connect: Connection terminated

cannot open mixer: Connection refused

see attached file.
What am I doing wrong?

 

[oguz]

did you convert the container to privileged?

also what is your container config like? can you post it here?

maybe the second post in the thread you mentioned is a better solution

 

[Yashalta]

also what is your container config like? can you post it here?

Here is my container config, witch one located on the host.

arch: amd64
cores: 2
hostname: player
memory: 1024
net0: name=eth0,bridge=vmbr0,firewall=1,gw=192.168.18.1,hwaddr=76:6B:A1:1A:84:E$
ostype: debian
rootfs: local-lvm:vm-104-disk-0,size=15G
swap: 1024
unprivileged: 0
lxc.mount.entry: /dev/snd dev/snd none bind,create=dir,optional 0 0
lxc.cgroup.devices.allow: c 116:* rwm

maybe the second post in the thread you mentioned is a better solution

Yes, I do according to this instruction https://forum.proxmox.com/threads/forward-alsa-audio-to-lxc-container.45310/#post-215942
I have no other options!

I think, I guess what my problem is, but I don’t know how to solve it!
The problem is privileges!
If I run a container with a value "unprivileged: 0" then i see this

sound@player:~$ ls -all /dev/snd/
total 0
drwxr-xr-x 3 root root      280 Apr 25 07:16 .
drwxr-xr-x 7 root root      480 Apr 25 08:23 ..
drwxr-xr-x 2 root root       80 Apr 25 07:16 by-path
crw-rw---- 1 root audio 116,  4 Apr 25 07:16 controlC0
crw-rw---- 1 root audio 116, 10 Apr 25 07:16 controlC1
crw-rw---- 1 root audio 116,  8 Apr 25 07:16 hwC1D0
crw-rw---- 1 root audio 116,  9 Apr 25 07:16 hwC1D3
crw-rw---- 1 root audio 116,  3 Apr 25 07:16 pcmC0D0c
crw-rw---- 1 root audio 116,  2 Apr 25 07:16 pcmC0D0p
crw-rw---- 1 root audio 116,  6 Apr 25 07:16 pcmC1D0c
crw-rw---- 1 root audio 116,  5 Apr 25 07:43 pcmC1D0p
crw-rw---- 1 root audio 116,  7 Apr 25 07:16 pcmC1D3p
crw-rw---- 1 root audio 116,  1 Apr 25 07:16 seq
crw-rw---- 1 root audio 116, 33 Apr 25 07:16 timer

user is "root" and groop is "audio"!

and if, I run a container with a value "unprivileged: 1" then i see this

sound@player:~$ ls -all /dev/snd/
total 0
drwxr-xr-x 3 nobody nogroup     280 Apr 25 07:16 .
drwxr-xr-x 6 root   root        460 Apr 25 08:45 ..
drwxr-xr-x 2 nobody nogroup      80 Apr 25 07:16 by-path
crw-rw---- 1 nobody nogroup 116,  4 Apr 25 07:16 controlC0
crw-rw---- 1 nobody nogroup 116, 10 Apr 25 07:16 controlC1
crw-rw---- 1 nobody nogroup 116,  8 Apr 25 07:16 hwC1D0
crw-rw---- 1 nobody nogroup 116,  9 Apr 25 07:16 hwC1D3
crw-rw---- 1 nobody nogroup 116,  3 Apr 25 07:16 pcmC0D0c
crw-rw---- 1 nobody nogroup 116,  2 Apr 25 07:16 pcmC0D0p
crw-rw---- 1 nobody nogroup 116,  6 Apr 25 07:16 pcmC1D0c
crw-rw---- 1 nobody nogroup 116,  5 Apr 25 07:43 pcmC1D0p
crw-rw---- 1 nobody nogroup 116,  7 Apr 25 07:16 pcmC1D3p
crw-rw---- 1 nobody nogroup 116,  1 Apr 25 07:16 seq
crw-rw---- 1 nobody nogroup 116, 33 Apr 25 07:16 timer

user is "nobody" and groop is "nogroup"!

And, I can’t to change the privileges!

sound@player:~$ sudo chown root:audio /dev/snd/*
chown: changing ownership of '/dev/snd/by-path': Operation not permitted
chown: changing ownership of '/dev/snd/controlC0': Operation not permitted
chown: changing ownership of '/dev/snd/controlC1': Operation not permitted
chown: changing ownership of '/dev/snd/hwC1D0': Operation not permitted
chown: changing ownership of '/dev/snd/hwC1D3': Operation not permitted
chown: changing ownership of '/dev/snd/pcmC0D0c': Operation not permitted
chown: changing ownership of '/dev/snd/pcmC0D0p': Operation not permitted
chown: changing ownership of '/dev/snd/pcmC1D0c': Operation not permitted
chown: changing ownership of '/dev/snd/pcmC1D0p': Operation not permitted
chown: changing ownership of '/dev/snd/pcmC1D3p': Operation not permitted
chown: changing ownership of '/dev/snd/seq': Operation not permitted
chown: changing ownership of '/dev/snd/timer': Operation not permitted

Or it should be like this?