Improve PodEvictor observability through EvictOptions

[tioxy]

What type of PR is this?

/kind feature

What this PR does / why we need it:

Supports profile name set under the label profile for the metric pods_evicted.

This allows the possibility of alerting different severities for different profiles.

Also, some refactors related to EvictOptions to make it more standard.

Which issue(s) this PR fixes:

NONE

Special notes for your reviewer:

I really do not think ProfileName as a public function was the best idea for PodEvictor, but adding to NewPodEvictor would require changes over many lines of code. Any suggestions on how to improve it?

Already discussed in the comments.

Results for v1alpha1

Config

apiVersion: "descheduler/v1alpha1"
kind: "DeschedulerPolicy"
strategies:
  "PodLifeTime":
     enabled: true
     params:
       podLifeTime:
         maxPodLifeTimeSeconds: 5
         states:
         - "Running"
         - "Pending"
         - "PodInitializing"
  "RemoveFailedPods":
     enabled: true
     params:
       failedPods:
         reasons:
         - "NodeAffinity"
         includingInitContainers: true
         excludeOwnerKinds:
         - "Job"
         minPodLifetimeSeconds: 5

Metric output

// + profile="strategy-RemoveFailedPods-profile"
descheduler_pods_evicted{namespace="local-path-storage",node="kind-control-plane",profile="strategy-RemoveFailedPods-profile",result="success",strategy="PodLifeTime"} 2

Results for v1alpha2

Config

apiVersion: descheduler/v1alpha2
kind: DeschedulerPolicy
profiles:
  - name: profile-01
    pluginConfig:
    - name: PodLifeTime
      args:
        maxPodLifeTimeSeconds: 5
        states:
        - Running
        - Pending
        - PodInitializing
    - name: RemoveFailedPods
      args:
        reasons:
        - OutOfcpu
        - CreateContainerConfigError
        includingInitContainers: true
        excludeOwnerKinds:
        - Job
        minPodLifetimeSeconds: 5
    plugins:
      deschedule:
        enabled:
          - PodLifeTime
          - RemoveFailedPods

Metric output

// + profile="profile-01"
descheduler_pods_evicted{namespace="local-path-storage",node="kind-control-plane",profile="profile-01",result="success",strategy="PodLifeTime"} 2

Does this PR introduce a user-facing change?

Metric `pods_evicted` gained `profile` label

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

NONE

[k8s-ci-robot]

Hi @tioxy. Thanks for your PR.

I'm waiting for a kubernetes-sigs member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[jklaw90]

/ok-to-test

[tioxy]

@a7i Tried following the suggestion of using EvictOptions. Also added support for StrategyName and deprecated context references for it.

Thank you for the patience and attention! 😀 👍

[a7i]

really good changes and clean-up 🏆

[a7i]

/label tide/merge-method-squash
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: a7i

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[a7i]

/lgtm

Thank you for your contribution and patience! 🏆

[tioxy]

Just realized another change was missing here.

#1358