Upgrade manager should collect and expose metrics

[sandeepbhojwani]

Is this a BUG REPORT or FEATURE REQUEST?:
FEATURE REQUEST
What happened:

• Upgrade manager should expose some useful metrics that can be used for monitoring, automation, etc
• It will be best to expose the metrics in prometheus format
• Bonus will be a grafana dashboard :)

What you expected to happen:

How to reproduce it (as minimally and precisely as possible):

Anything else we need to know?:

Environment:

• rolling-upgrade-controller version
• Kubernetes version :

$ kubectl version -o yaml

Other debugging information (if applicable):

• RollingUpgrade status:

$ kubectl describe rollingupgrade <rollingupgrade-name>

• controller logs:

$ kubectl logs <rolling-upgrade-controller pod>

[shaoxt]

the features have been done in controller v2 #189

[sahilbadla]

I think there's more work that needs to be done here. According to the epic, here are the sub tasks:

• Focus on metrics that indicate the progress of the upgrade and if it is "stuck"
• For each CR/IG, number of nodes needed to be upgraded, number of nodes completed and number of nodes remaining. An alert could be put on non-zero values of nodes remaining not changing within a specific time period