fix(loadbalancers): ip_port_mapping is overwritten by new vips

[SkalaNetworks]

Pull Request

• Make sure you have followed Kube-OVN Code Style.

What type of this PR

• Bug fixes

There's a problem with SwitchLBRules right now:

• The ip_port_mapping is overwritten for any new SLR
• That means new SLRs will break previous ones

I seem to be the one that introduced this regression a few month back. This fixes it by adding ip_port_mappings one after another.

The GC will take care of cleaning up ip_port_mappings if some become stale.

[gemini-code-assist]

Summary of Changes

Hello @SkalaNetworks, 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 resolves a critical bug in the OVN load balancer management where the IP port mappings were inadvertently being reset or overwritten when new load balancer rules were applied. The fix ensures that mappings are added cumulatively, preserving existing configurations and preventing service disruptions. This change improves the stability and reliability of load balancer operations within the system.

Highlights

• Bug Fix: IP Port Mapping Overwrite: Addressed a regression where ip_port_mapping in OVN load balancers was being overwritten by new SwitchLBRules (SLRs), causing previous SLRs to break.
• Load Balancer Update Logic: Modified the LoadBalancerUpdateIPPortMapping function to incrementally add ip_port_mappings rather than attempting to delete and then add, which was causing the overwrite issue. Existing mappings will now persist.
• Garbage Collection Reliance: Confirmed that the garbage collector will handle the cleanup of any stale ip_port_mappings that are no longer needed, removing the necessity for manual deletion logic within this function.

Changelog

• pkg/ovs/ovn-nb-load_balancer.go
  • Removed logic that incorrectly deleted ip_port_mapping entries, which led to overwriting existing mappings.
  • Ensured that new ip_port_mappings are added without affecting previously configured ones.

Activity

• No specific activity (comments, reviews) has been recorded on this pull request yet.

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[gemini-code-assist]

Code Review

This pull request correctly fixes a bug where ip_port_mapping entries for existing services were being overwritten when a new service was added or an existing one was updated. The previous implementation incorrectly tried to clean up stale mappings, but ended up removing valid mappings for other services. By removing the faulty deletion logic and relying only on the insert operation, the change ensures that mappings are added cumulatively. As noted in the description, a separate garbage collection process will handle the cleanup of stale entries, making this change safe and effective. The fix is clear and addresses the regression.

[SkalaNetworks]

@oilbeater this bug is breaking SLRs in custom VPCs, the fix seems to work on my clusters.