Cilium Multihoming
The multi-homed node from the previous post has two equal-cost layer 3 uplinks. The kernel’s multipath hash never sees the flow — Cilium’s bpf_fib_lookup carries L3 only. Feeding it the flow label and the L4 ports makes ECMP real, on the default hash policy. With the help of AI coding with my stupid ideas, cilium distributes traffic to both uplinks.