[SOLVED] WARN: old systemd (< v232) detected, container won't run in a pure cgroupv2 environment!

[ramses]

Hi everyone,

I have upgraded PVE v6.4 to PVE v7.2-7 and all works fine except LXC that I have.

When I try to start the LXC container:

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root@proxmox:/etc/pve/lxc# pct start 120
WARN: old systemd (< v232) detected, container won't run in a pure cgroupv2 environment! Please see documentation -> container -> cgroup version.
Task finished with 1 warning(s)!
root@proxmox:/etc/pve/lxc#
----------------------------------------------------------------

The config CT is this (Debian 8 / Jessie):

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root@proxmox:/etc/pve/lxc# pct config 120
arch: amd64
cores: 1
description: lxc.cgroup2.devices.allow = c 10%3A200 rwm%0A
hostname: soporte
memory: 1024
nameserver: 8.8.8.8 8.8.4.4
net0: name=eth0,bridge=vmbr0,gw=192.168.2.1,hwaddr=96:7F:45:EC:57:E8,ip=192.168.2.95/24,type=veth
onboot: 1
ostype: debian
rootfs: local-lvm:vm-120-disk-1,size=40G
searchdomain: soporte.local
swap: 1024
root@proxmox:/etc/pve/lxc#
----------------------------------------------------------------

I have tried to add the line GRUB_CMDLINE_LINUX_DEFAULT="systemd.unified_cgroup_hierarchy=0 quiet" to GRUB but the LXC CT haven't the GRUB files:

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root@soporte:/# ls -la /etc/default/grub
ls: cannot access /etc/default/grub: No such file or directory
root@soporte:/# ls /boot/grub/grub.conf
ls: cannot access /boot/grub/grub.conf: No such file or directory
root@soporte:/#
----------------------------------------------------------------

I have created the "/etc/default/grub" file with the line GRUB_CMDLINE_LINUX_DEFAULT="systemd.unified_cgroup_hierarchy=0 quiet" but when I try to update the GRUB:

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root@soporte:/# update-grub
bash: update-grub: command not found
root@soporte:/#
----------------------------------------------------------------

I can enter to the CT and start the network with the service networking start and have access to Internet but it not start automatically and all services are stoped but I can start, by example, the ssh server service manually.

What can I do to solve this error the LXC CT?


Regards and thanks so much

 

[Neobin]

The config CT is this (Debian 8 / Jessie)

I am not going to ask, why you are using a OS-version, that is EOL since over 4 years (normal) and over 2 years (LTS)...

I have tried to add the line GRUB_CMDLINE_LINUX_DEFAULT="systemd.unified_cgroup_hierarchy=0 quiet" to GRUB but the LXC CT haven't the GRUB files

You need to add this parameter on your PVE-host, not the LXC:
https://pve.proxmox.com/pve-docs/chapter-pct.html#pct_cgroup_compat ("Changing CGroup Version")

 

[ramses]

I am not going to ask, why you are using a OS-version, that is EOL since over 4 years (normal) and over 2 years (LTS)...



You need to add this parameter on your PVE-host, not the LXC:
https://pve.proxmox.com/pve-docs/chapter-pct.html#pct_cgroup_compat ("Changing CGroup Version")

@Neobin thanks so much

My LXC CT starts fine now.

Thanks so much again.

 

[zPro]

Will the solution also work on Proxmox 8? Ist there any drawback for Proxmox itself?

 

[Neobin]

Will the solution also work on Proxmox 8? Ist there any drawback for Proxmox itself?

cgroup V1 Deprecation

Reminder, since the previous major release Proxmox VE 7.0, the default is a pure cgroupv2 environment. While Proxmox VE 8 did not change in this regard, we'd like to note that Proxmox VE 8 will be the last release series that supports booting into the old "hybrid" cgroup system, e.g. for compatibility with ancient Container OS.

That means that Containers running systemd version 230 (released in 2016) or older won't be supported at all in the next major release (Proxmox VE 9, ~ 2025 Q2/Q3). If you still run such container (e.g., CentOS 7 or Ubuntu 16.04), please use the Proxmox VE 8 release cycle as time window to migrate to newer, still supported versions of the respective Container OS.

https://pve.proxmox.com/wiki/Upgrade_from_7_to_8#cgroup_V1_Deprecation

 

[zPro]

oh many thanks hybrid is still supported with Proxmox 8, I though I read that this is already not possible... just tried & runs fine after adding to grub.

For future I have to see, but one older Server does only run in Ubuntu 16, so need to see if e.g. docker can help in future... Changing the tool I surely cannot do...