runc: Missing pieces running rootless containers on RHEL 7.4 + Documentation

Running containers in a rootless manner isn’t straight forward on RHEL 7.4 as I excepted. I willing to write some extra documentation about getting rootless containers up-and-running on RHEL 7.4 if I can find the last piece of information how to solve the issue I have.

How to reproduce:

• Provision a Node and install a clean RHEL 7.4
• Install the latest runc (1.0.0-rc5)
• Make some adjustments to the Kernel to enable user namespaces (namespace.unpriv_enable=1 user_namespace.enable=1)
• Change the settings to allow to create user namespaces (sudo echo "user.max_user_namespaces=15000" >> /etc/sysctl.conf)
• Run the runc test script to check if we all good @ https://github.com/opencontainers/runc/blob/master/script/check-config.sh
• Create a rootless container using the instruction @ https://github.com/opencontainers/runc/blob/master/README.md#rootless-containers
• runc --root /tmp/runc run mycontainerid

I got an error:

container_linux.go:348: starting container process caused "process_linux.go:301: running exec setns process for init caused \"exit status 47\""

I think I’m close. Any one having a glue what I miss? I also disabled SELinux to be sure.

If I got this working I will change the documentation and test-script to make sure all RHEL users can experience the awesome power of rootless containers!