Add monitoring to OSDK

[adellape]

JIRA: https://jira.coreos.com/browse/OSDOCS-11

New Configuring built-in monitoring with Prometheus topic:

http://file.rdu.redhat.com/~adellape/021919/osdk_metrics/applications/operator_sdk/osdk-monitoring-prometheus.html

[vikram-redhat]

@rh-max can you review to make sure this is still correct?

[openshift-docs-preview-bot]

The preview will be availble shortly at:

• https://osdk_metrics--ocpdocs.netlify.com/

[adellape]

@lilic What should this be added to?

[lilic]

Wherever in the users operator code.

[adellape]

@lilic Should "namespace" be a replaceable? services?

[lilic]

services are meant in this case an array of kubernetesService objects the user creates for metrics exposing.

Yes "namespace" is a silly example I guess, should include the signature of the function as well. It's the name of the Namespace in which the ServiceMonitor will be created.

CreateServiceMonitors(config *rest.Config, ns string, services []*v1.Service)

[lilic]

FYI I updated the original docs PR a bit.

[ahardin-rh]

@adellape LGTM! 💯

[adellape]

@lilic @ahardin-rh Thanks for the reviews! Updated with my latest understanding. Going to merge to get this in for QE review, and we can continue iterating from there.

Also cc @joelanford since you were reviewing the upstream operator-framework/operator-sdk#719 as well.