WIP: EL8 installer

[punkrokk]

Done so far

• Create EL8 Packages in staging-unstable
• Prep Vagrantfile
• Update st2bootstrap scripts (This PR)
• Author (@punkrokk) testing
• You test

Updates for EL8:

• RabbitMQ on RHEL 8 requires: sudo yum -y module enable perl:5.26
• Currently need the rabbit packagecloud repo:

# Install rabbit from packagecloud
  curl -s https://packagecloud.io/install/repositories/rabbitmq/rabbitmq-server/script.rpm.sh | sudo bash
  sudo yum makecache -y --disablerepo='*' --enablerepo='rabbitmq_rabbitmq-server'

• selinux policy utils package name is different: policycoreutils-python -> policycoreutils-python-utils
• modify [includes/common.sh](https://github.com/StackStorm/st2-packages/blob/f0e1e650d17ccee9c8e4ab05bfdbd1a664378089/scripts/st2bootstrap-el8.sh#L256-L260) to force PEM key type.
• MongoDB to 4.0 (Readme not updated yet)

See StackStorm/st2docs#955 more differences from EL7 -> EL8.

How I am testing

Here is a reasonably plain Vanilla Vagrantfile that I'm using. Main difference is 4 CPUs and 4GB of RAM and a Private Network static IP. YMMV.
https://gist.github.com/punkrokk/36db930d50d0a272c93ae6049919bf5c

Vagrant setup

mkdir el8test && cd el8test
[copy above or your own Vagrantfile in this dir
vagrant up --provider virtualbox && vagrant ssh

In Vagrant box or your CentOS 8 VM: :

sudo yum -y install git
git clone https://github.com/StackStorm/st2-packages.git
cd st2-packages
git checkout el8-install-testing 
cd scripts
bash st2bootstrap-el8.sh  --unstable --staging  --user=st2admin --password=Ch@ngeMe

Please comment here if you:

• Succeed (Thumbs up this PR)
• Find a bug (Comment or request a change and explain why/what)

[punkrokk]

The vagrant docker provisioner is currently broken for CentOS 8

• vm_config.vm.provision :docker fails on CentOS 8 hashicorp/vagrant#11330

[arm4b]

Talking about installer script, I left several comments to address in previous PR related to el8 bootstrap sh:
#630 (review)

[arm4b]

Looks we're close with the EL8 scripted installer 👍

Next stage would be asking existing @StackStorm/maintainers + Contributors to test the EL8 bootstrap script manually and report back if anything weird, bugs or improvements found and if installation succeeds or not in different environments.
I'll try to run the script myself as well.

The instructions to run it on EL8 (RHEL8 or CentOS8) once we merge this PR:

curl -sSL https://stackstorm.com/packages/install.sh | bash -s -- --staging --unstable

[arm4b]

Fun fact: rabbitmq-server is installing 160 other packages via dependencies, including Java.
This experience is similar to nodejs that's pulling python as a dependency for st2chatops package we ship 🤕

[punkrokk]

@armab FYI - epel is required for rabbitmq dependencies (erlang specifically)

[arm4b]

LGTM 👍

Thanks for the extra effort testing it!
We'll need also another cycle and community/maintainer/contributors help in #development to run & test EL8 installer after merging.