feat: Grant additional access for Groups & Recocile logic for masterRole Changes & Metrics Support

[tkcontiant]

I notice we are missing sequences and functions access.

• Owner-Group user should have Grant ALL, as it will most likely be used for Flyway migrations, etc.

ownerPrivs          = "ALL"
ownerFunctionPrivs  = "ALL"
ownerSequencePrivs  = "ALL"

The Second Writer-Group should have limited access to Sequences and execute the Functions.

writerSequencePrivs = "USAGE,SELECT"
writerFunctionPrivs = "EXECUTE"

Reader-Group remains the same

Update Owner-Group if the masterRole was renamed or changed

• I assume the operator needs to keep the state always, as defined in the CRD

Re-assign the user group membership

• My user was a reader, and I needed to be part of a writer or owner group.

Leader election

• Enable Leader election for the operator, allowing the organizations to run the operator in HA mode
• Update the RBAC so Operator can access the correct privileges to acquire the leader lock
• Enable the Prometheus metrics endpoint

PodMonitor

Added for Prometheus Operator Discovery
PodMonitor

Enable Metrics

• Useful metrics are already available

# TYPE controller_runtime_reconcile_total counter
controller_runtime_reconcile_total{controller="postgres",result="error"} 0
controller_runtime_reconcile_total{controller="postgres",result="requeue"} 0
controller_runtime_reconcile_total{controller="postgres",result="requeue_after"} 0
controller_runtime_reconcile_total{controller="postgres",result="success"} 0
controller_runtime_reconcile_total{controller="postgresuser",result="error"} 0
controller_runtime_reconcile_total{controller="postgresuser",result="requeue"} 0
controller_runtime_reconcile_total{controller="postgresuser",result="requeue_after"} 0
controller_runtime_reconcile_total{controller="postgresuser",result="success"} 0

[pcallewaert]

Thanks, I like all these improvements. Some feedback added.

[tkcontiant]

Thanks, I like all these improvements. Some feedback added.

Thanks for the review. I believe we are ready.

[itek09]

Nice PR, I'm affected by the same

[tkcontiant]

Nice PR, I'm affected by the same

I am looking forward to being approved and merged. You can take the PR Source Code and do a local Docker build.

docker build . -t postgres-operator:v1

The next topic on the horizon is the monitoring role. I am still clarifying how is going to look like on my end.
I hope I am able to have a fully compatible postgres-exporter and pgwatch monitoring role managed by the operator at some point.