Add support for CentOS (Stream) 8

[blaztinn]

With these changes I've successfully installed and have been using the server (with a few bridges) on the CentOS Stream 8. AFAIK, everything seems to be working as it should.

This PR is basically more of a request for comments. I don't know enough Ansible to replace ntp/ntpd with chrony/chronyd only for CentOS 8+.

Also, docker-py is installed through pip since I couldn't find it in any repos (checked CentOS and EPEL). Is that a good enough solution?

[spantaleev]

Thanks for thinking about making the playbook run on newer distros!

Looks like this PR would break installation on older distros (which don't have chrony).

Since systemd is already a hard dependency for us, using something like systemd's timesyncd for such newer distros is better than using ntp/chrony. See our discussion in #1029.

It's also good to separate the CentOS 8-Stream setup tasks into another YAML file, and to make setup_centos.yml only run for older CentOS. You'd then make your changes in your new file (setup_centos8_stream.yml).

[blaztinn]

Thanks, I'll look into it and update the PR :)

[blaztinn]

I've updated the PR to use systemd-timesyncd and made a separate setup setup_centos8.yml.

Because checking for CentOS vs CentOS Stream needs quite recent Ansible (ansible/ansible#73034) not yet packaged by my distro, I've made the setup available for all CentOS 8+. Looking at the packages mirror of CentOS 8 I believe that the setup should also work for that release but I haven't tested it. I have only tested it on CentOS 8 Stream.

For using the systemd-timesyncd I needed to add a task to install EPEL repos, I hope that's OK? Otherwise I'll change it back to chrony.

[spantaleev]

I guess this (using pip, installing epel-release) is better than not having any CentOS 8 support at all, so I'm merging it as it is. Thank you! 👍

Should we find a way to improve it in the future, we can.