Remove Divisor from Downward API resrouceFieldRefs

[andrewlecuyer]

Remove divisor from Downward API resrouceFieldRefs. This means CPU and memory information will now be exposed using the default divisor for CPU and memory (with default being "1" for both). This means memory information will now be represented in bytes, as expected by pgMonitor and the CPK Metrics & Monitoring stack when consuming Downward API information.

Checklist:

• Have you added an explanation of what your changes do and why you'd like them to be included?
• Have you updated or added documentation for the change, as applicable?
• Have you tested your changes on all related environments with successful results, as applicable?
  • Have you added automated tests?

Type of Changes:

• New feature
• Bug fix
  Fixes memory metrics in the Metrics & Monitoring stack.
• Documentation
• Testing enhancement
• Other

What is the current behavior (link to any open issues here)?
The divisor for the Downward API volumes for CPU and memory defaults to 1m for CPU and 1Mi for memory.

What is the new behavior (if this is a feature change)?

• Breaking change (fix or feature that would cause existing functionality to change)
  Potential breaking behavior if anyone is consuming Downward API info via a custom sidecar.

Other Information:

Issue: PGO-2604

[benjaminjb]

The default divisor is "1" (reasonable) but in reconcile_test.go, it looks like "0" (maddening)?

[andrewlecuyer]

@benjaminjb agreed! Looks like without a full Kube running we won't get the default of 1.

[benjaminjb]

We'll want a release note for this, but I can't think of any other docs that need to change, can you?

[andrewlecuyer]

Just noting that I tested this with the monitoring stack, and everything looks good.

E.g. for this spec:

apiVersion: postgres-operator.crunchydata.com/v1beta1
kind: PostgresCluster
metadata:
  name: hippo
  namespace: postgres-operator
spec:
  instrumentation: {}
  postgresVersion: 17
  instances:
    - name: instance1
      replicas: 2
      resources:
        requests:
          cpu: 1
          memory: "1Gi"
      dataVolumeClaimSpec:
        accessModes:
        - "ReadWriteOnce"
        resources:
          requests:
            storage: 1Gi

I see this on the file system:

$ cat mem_request
1073741824
$ cat cpu_request
1

And then the dashboard accurately reflects the memory reqiest:

[andrewlecuyer]

@benjaminjb agreed, release notes should be sufficient.