Kata claims to support rootless, but I fail to achieve that in many machines.

[zibinpan]

I followed the instruction to set the rootless for kata, and followed the doc to set the rootless for containerd. However, when I tried to run the following command to create a container in rootless:

ctr run --runtime "io.containerd.kata.v2" -t docker.io/library/ubuntu:20.04 ubuntu_20

It raised an error of:

ctr: failed to unmount /run/user/1001/containerd-mount2863814794: operation not permitted: failed to mount /run/user/1001/containerd-mount2863814794: operation not permitted

So, is there any successful and complete demo telling me how to run a rootless container by kata in detail?

My Host OS is Ubuntu 18.04, kernel 5.4.0.150-generic, (also tried and failed in Ubuntu 22.04 in kernel of 6.5.0-28-generic).

My kata-container version is 3.3.0, and containerd version is 1.7.14.