Add E2E test for Locality Load Balancing

[ravjot07]

Overview

This PR adds an end-to-end integration test (TestLocalityLoadBalancing) for the Locality Load Balancing feature in Kmesh. The goal is to validate the PreferClose traffic distribution policy by simulating a real-world scenario with services deployed in different zones. The test ensures that:

• Traffic from a local client is served by the closest available service instance (based on node locality).

• When the closest instance becomes unavailable, traffic is gracefully routed to a remote instance.

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Test Flow

Namespace Creation

A new namespace sample is created for the test resources.

Service Deployment

The helloworld service is deployed with:

trafficDistribution: PreferClose

Backend Deployments

Two deployments of the helloworld app are launched:

• Local Instance: On node kmesh-testing-worker, labeled as region.zone1.subzone1.

• Remote Instance: On node kmesh-testing-control-plane, labeled as region.zone1.subzone2.

Each instance responds with its own SERVICE_VERSION.

Sleep Client Deployment

A curl-based client (sleep) is deployed on kmesh-testing-worker to simulate client-side traffic origin.

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Verification

1. Resolution Check: Uses nslookup to resolve the FQDN of the service from within the client pod.

2. Initial Routing: Makes curl requests to helloworld.sample.svc.cluster.local expecting responses from the local instance (region.zone1.subzone1).

3. Failover Simulation: Deletes the local deployment and retries the curl until a response is returned from the remote instance (region.zone1.subzone2).

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Cleanup

The test framework handles namespace and deployment cleanup automatically after test execution.

Contributes toward #1146

[kmesh-bot]

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[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 45.48%. Comparing base (e5ead63) to head (7035aaa). Report is 6 commits behind head on main.

see 2 files with indirect coverage changes

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[hzxuzhonghu]

/retest

[YaoZengzeng]

@ravjot07 Try to fix the comments and get this PR merged.

Get code merged is what really matters.

[kmesh-bot]

Adding label do-not-merge/contains-merge-commits because PR contains merge commits, which are not allowed in this repository. Use git rebase to reapply your commits on top of the target branch. Detailed instructions for doing so can be found here.

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