cache root pw in file outside of mounted volumes

[zzzeek]

Don't write root pw in /var/lib/mysql which is volume mounted. Also, instead of using /etc or /etc/my.cnf.d, we dont want a mysql-owned writable file in /etc which is also considered to be server configuration so
since we don't actually need mariadb tools to find this file, instead write to an arbitrary file in a non-mounted directory like /var/local/mysql_pw_cache.cnf.

[openshift-ci]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: zzzeek
Once this PR has been reviewed and has the lgtm label, please ask for approval from dciabrin. For more information see the Code Review Process.

The full list of commands accepted by this bot can be found here.

Details

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[zzzeek]

/retest

[openshift-ci]

@zzzeek: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
ci/prow/mariadb-operator-build-deploy-chainsaw	dae44cb	link	true	/test mariadb-operator-build-deploy-chainsaw
ci/prow/mariadb-operator-build-deploy-kuttl	dae44cb	link	true	/test mariadb-operator-build-deploy-kuttl

Full PR test history. Your PR dashboard.

Details

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository. I understand the commands that are listed here.