feat(hubble): Add trafficDistribution field support for Kubernetes 1.31+

[younsl]

Description

Add trafficDistribution field support to Hubble services (excluding DaemonSet-connected services) with Kubernetes version compatibility check (≥1.31). This provides better performance and reliability than annotation-based topologyAwareRouting by being natively integrated into the Service API.

Changes:

• Added trafficDistribution configuration to Hubble Relay and UI services in values.yaml
• Updated service templates with conditional rendering based on Kubernetes version
• Excluded DaemonSet-connected services (agent, peer) as they use hostNetwork

Usage

Retina administrators can now set hubble.relay.service.trafficDistribution: PreferClose or hubble.ui.service.trafficDistribution: PreferClose in their values to enable topology-aware routing with improved performance characteristics.

Related Issue

• Comparison with service.kubernetes.io/topology-mode: Auto: Kubernetes official doc

Checklist

• I have read the contributing documentation.
• I signed and signed-off the commits (git commit -S -s ...). See this documentation on signing commits.
• [ x I have correctly attributed the author(s) of the code.
• I have tested the changes locally.
• I have followed the project's style guidelines.
• I have updated the documentation, if necessary.
• I have added tests, if applicable.

Screenshots (if applicable) or Testing Completed

Please add any relevant screenshots or GIFs to showcase the changes made.

Additional Notes

Why trafficDistribution over topologyAwareRouting?

The trafficDistribution field is recommended over topologyAwareRouting annotations as it provides native Kubernetes Service API integration with better performance and reliability characteristics. This field is available in Kubernetes 1.31+ and offers more granular control over traffic routing behavior compared to the annotation-based approach.

---
title: topologyAwareRouting vs trafficDistribution
---
graph LR
    A[K8s < 1.31] --> B["`**topologyAwareRouting**
    Annotation (Legacy)`"]
    C[K8s ≥ 1.31] --> D["`**trafficDistribution**
    PreferClose`"]
    
    B --Migration--> D 
    B --> F["`Inter AZ DTO Cost
    Reduction`"]
    D --> F

    style D fill:darkorange, color:white
    style B stroke:red, color:white

    note["As of Kubernetes 1.31, the trafficDistribution feature has been moved to beta."]

    style note fill:transparent, stroke:transparent, color:lightgray

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