Compatibility Warning: Container Requires systemd v232+ for cgroupv2 Environment

How to Resolve LXC Startup Error on Proxmox from v6 to v7

If you encounter the following warning when starting an LXC container after upgrading from Proxmox v6 to v7:

WARN: old systemd (< v232) detected, container won't run in a pure cgroupv2 environment! Please see documentation -> container -> cgroup version.

Here is a solution to address this issue:

  1. Edit the GRUB configuration file on your Proxmox 7 server using a text editor like nano:

    nano /etc/default/grub
  2. Locate the GRUB_CMDLINE_LINUX_DEFAULT parameter.

  3. Add the following configuration to the line, preserving the existing parameters:

    quiet systemd.unified_cgroup_hierarchy=0

    The line should look like this:

    GRUB_CMDLINE_LINUX_DEFAULT="quiet systemd.unified_cgroup_hierarchy=0"
  4. Save the file.

  5. Run the following command to update the GRUB configuration:

  6. Restart the server to apply the changes:


By adding systemd.unified_cgroup_hierarchy=0 to the GRUB configuration, you revert the CGroup version to version 1. Proxmox 7 predominantly uses version 2, but this adjustment will ensure compatibility.

Alternatively, you can consider either installing a newer version of systemd or migrating your machine to CentOS 8 or a more recent distribution.

If you require further assistance, it is recommended to reach out to Proxmox support for additional help and guidance.

beware, if you copy/paste this config line verbatim line, the quotes come out wrong. you don’t want mistakes in your grub config!

it should be this:
GRUB_CMDLINE_LINUX_DEFAULT=“quiet systemd.unified_cgroup_hierarchy=0”

and not this:
GRUB_CMDLINE_LINUX_DEFAULT=“quiet systemd.unified_cgroup_hierarchy=0”

Thanks @darxtorm now the quotes are fixed, you can copy and paste.