Add distribution detection logic

[rtorrero]

This PR adds:

• A check in the pre_tasks of the playbook. The check will prevent the execution on distributions others than SLES for SAP 15 SP3, SP4 or SP5
• A conditional that executes the expect workaround that manually installs the user/group for prometheus. This conditional will ensure that the workaround is only executed when needed (SP4 and SP5)
• Changes yaml formatting for the playbook so that we use 2 spaces for indentation. I've seen this in most of YAML guidelines and my formatter follows this also. I can remove it if we prefer to stay with 1-space.

I've checked the logic in all 3 supported targets and it works as expected

[arbulu89]

Hey @rtorrero,
I guess that this approach is good enough if the differences are so small.
There are other strategies like having specific variables files per distro for more advanced use cases.
My unique concern again is the PR environment, which I think we start failing again.
What do you have in mind for that?

[arbulu89]

We need to check if we need to accept openSUSE leap as well.
Otherwise the PR environment workflow will start failing, as It is not based on SLES4SAP (but i'm not sure if it is based in Leap neither)

[rtorrero]

Not sure, let's discuss it today in the daily 👍

[arbulu89]

I think we need some yaml linter here

[rtorrero]

I would go for the double-space indenting that is used more extensively. Should we enforce this in the CI?

[arbulu89]

I don't really care, as long as we don't do this "out of the blue" changes

[CDimonaco]

Same comments as @arbulu89, also we need to support LEAP, for the pr env itself and also for Vagrant usage/testing

We can go with the latest leap version, changing the Vagrant box ofc

[rtorrero]

@CDimonaco @arbulu89 changes applies, except for the linting. I would like to address that separately as we need to change more than a few existing files. I will do that next and add https://github.com/marketplace/actions/yaml-lint to the CI, wdyt?

[CDimonaco]

@CDimonaco @arbulu89 changes applies, except for the linting. I would like to address that separately as we need to change more than a few existing files. I will do that next and add https://github.com/marketplace/actions/yaml-lint to the CI, wdyt?

Please check locally on the machine if yaml lint and ansible-lint conficts, ansible lint has already some rules on formatting the yaml files

[arbulu89]

I would personally remove all the linting changes, and apply them once we have some linting rules

[arbulu89]

I don't really care, as long as we don't do this "out of the blue" changes