Support High Availability of Private MetalnetLBs across Multiple AZs

[hardikdr]

Summary

This is an issue concerning the High Availability (HA) of Private MetalnetLBs in the net-dp-service. The current behavior of the service does not support ECMP (Equal-Cost Multi-Path), which limits the ability to use multiple private load balancers in a HA mode.

In the scenario of Private MetalnetLBs, traffic is not routed through the router. As a result, only a single copy of a Private MetalnetLB can exist within a given VNI, in a given VM-cluster. This restriction impedes the ability to spread PrivateLB across multiple Availability Zones (AZs).

Basic example

In cases where there are multiple AZ/VM-clusters, each having its own copy of a given API-PrivateLB (in turn a copy of PrivateMetalnetLB), where the same Network is spread across multiple clusters/AZs, we encounter conflicts. This setup leads to the creation of multiple PrivateMetalnetLBs within a single VNI. Consequently, the load balancing functionality might not perform as expected.

Motivation

To ensure effective load balancing and the high availability of Private MetalnetLBs across multiple clusters and AZs.

[hardikdr]

cc @gehoern @guvenc @MarekNaster @FlorinPeter