[core] add pdb controller in ome

[pallasathena92]

What type of PR is this?

/kind feature

What this PR does / why we need it:

A Pod Disruption Budget (PDB) in Kubernetes is a resource that specifies the minimum number or percentage of pods that must remain available for an application during voluntary disruptions.
Add it to our service to ensure the availiblity and volutary disruptions.

Which issue(s) this PR fixes:

there are two mian parts of this pr:

1. add pdb controller
2. remove hpa reference deployment name modify we checked in for migration previously.
   during migration, we have add "-new" as suffix to deployment name. In current inference service behavior, the deployment name will be "xxx-engine" and "xxx-decoder".

Does this PR introduce a user-facing change?

None. There is no impact on user's experience.

[gemini-code-assist]

Summary of Changes

Hello @pallasathena92, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request introduces a new Pod Disruption Budget (PDB) controller to improve the resilience and availability of services by allowing users to define minimum availability or maximum unavailability constraints for pods during voluntary disruptions. Additionally, it refines the deployment naming convention by removing a legacy modification related to HPA references, ensuring more consistent resource identification. These changes collectively aim to bolster the stability of deployed applications.

Highlights

• Pod Disruption Budget (PDB) Support: Introduced a new PDB controller to manage Pod Disruption Budgets for service components, enhancing application availability during voluntary disruptions. This includes new MinAvailable and MaxUnavailable fields in component specifications.
• HPA Deployment Name Logic Removed: The logic that appended a '-new' suffix to deployment names for HPA references during migration has been removed, streamlining deployment naming conventions.
• Dependency Cleanup: Performed a significant cleanup of unused Go module dependencies in go.sum, reducing the overall project footprint and improving build efficiency.
• API Schema Updates: Updated the API schema (openapi_generated.go and swagger.json) to include the new minAvailable and maxUnavailable fields for component extension specifications.

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[gemini-code-assist]

Code Review

This pull request introduces a Pod Disruption Budget (PDB) controller to improve service availability during voluntary disruptions, which is a great addition. The implementation is well-integrated into the existing reconciliation logic. The PR also includes a cleanup of some legacy code related to HPA deployment naming from a previous migration.

My review includes a high-severity comment regarding the default PDB configuration, which could inadvertently cause downtime for single-replica services. I've also pointed out a couple of minor typos in the code comments that affect the generated API documentation. Overall, the changes are solid, and addressing the default PDB behavior would make this feature safer for all use cases.

[gemini-code-assist]

The default behavior of creating a PodDisruptionBudget with maxUnavailable: 1 can be risky for single-replica services, as it would allow the single pod to be voluntarily disrupted, causing downtime. To better ensure availability, consider not creating a PDB by default if neither minAvailable nor maxUnavailable is specified by the user. This would make PDB creation an explicit opt-in, which is safer. An alternative could be to default to maxUnavailable: 0 for single-replica deployments.