Extended OpenShift template for the Galera cluster

[desdrury]

I've extended the OpenShift template so that it can do the following.

• Define the root password (see Implement Galera Master-Master Replication #107). Stored in a Secret. Uses the OpenShift template variable MYSQL_ROOT_PASSWORD.
• Define a default user and password. Stored in the same Secret. Uses the OpenShift template variables MYSQL_USER and MYSQL_PASSWORD.
• Define a default database. Use the OpenShift template variable MYSQL_DATABASE.
• Added a Deployment and related Service that runs the Prometheus MySQL Exporter so that we can collect metrics to visualise in Grafana.

This has all been tested on a local MiniShift instance.

[Schnitzel]

Thanks!

We want to create an alpine mariadb first (#61), so we don't depend on any external images (like adfinissygroup/k8s-mariadb-galera-centos).

After that happy to look into that :)

[desdrury]

@Schnitzel do you have an ETA for when the Alpine MariaDB will be done? And if not before Governors, i.e. 22/12/2017, would Amazee support us running a version of the Galera cluster using the adfinissygroup/k8s-mariadb-galera-centos as an interim solution?

[Schnitzel]

pinging @rtprio for the question regarding MariaDB Images

[rtprio]

mariadb builds ok with the galera flags; I'm having several issues with building the associated wsrep tools on alpine. I do not think I'll have it ready to go by the 22nd.

At this time adfinissygroup/k8s-mariadb-galera-centos would be my second choice.

[rtprio]

I didn't mean to close this PR so swiftly but I'm tracking galera in #107