host system max_user_namespaces is set to 0

[klutchell]

When running this container on Ubuntu derivatives and using cgroups v1 as required, the host max_user_namespaces can get reset to 0 causing various issues on the host.

Linux system76 5.15.11-76051511-generic #202112220937~1640185481~21.04~b3a2c21-Ubuntu SMP Mon Jan 3 16:5 x86_64 x86_64 x86_64 GNU/Linux

Retrieve the current value with

sudo sysctl -a | grep max_user_namespaces

Can be restored with

echo 10000 | sudo tee /proc/sys/user/max_user_namespaces