added new variables that allow to disable the installation of some parts …

[lhoss]

…(like java, rngd, mysql)

Motivation:

• Allow to switch of the deployment parts we want to handle outside this playbook, in a more customized way
• disable Java installation: the included OracleJDK-7 deployment is outdated, and most people that deploy a new cluster are much better off with a JDK-8 (even openjdk8 is perfectly fine), more infos: Java role has (oracle)JDK v7 hardcoded #24
• disable Mysql installation: Useful if you want to use postgresql instead
  • for this see also added new variable database_type to switch between CDH supported databases… #30

[dbeech]

Would tags / skip_tags be a better way of achieving this?
https://docs.ansible.com/ansible/latest/user_guide/playbooks_tags.html

[lhoss]

Btw @dbeech is this 'temporary' workaround still needed in the playbook (maybe for older CDH 5.x versions ?).
During my initial tests with CDH 6.2, I had this part ignored, and the deployment worked (at least upto the CM install + configuration)

[dbeech]

No, I don't think this is required any more. The bug listed is 3 years old and wasn't even commonly encountered -- I think the original root cause was that selinux was enabled and this messed up the user creation through CM.

[lhoss]

OK, then I propose to get that whole logic out in a future PR
( but keep my addition in for now, assuming you are OK with the rest)

[lhoss]

Would tags / skip_tags be a better way of achieving this?

Simply using tags can be good enough in some cases, but it often gets problematic with tags outside the main playbook ( which would be required for the cluster_install_groups_users toggle)

To avoid creating a bunch of new 'group vars' (in the all file .. we should add the '.yml' extension btw for proper yml handling in editors, like VScode), I could make undocumented vars by changing the when check(s) to:

      when: cluster_install_rngd | default(true)