Donavan Fritz
e1e9544e2e
Build flock Image / build (push) Has been cancelled
The design doc's lo placement was motivated by avoiding NDP/ARP DAD conflicts "across nodes advertising the same IP" — but flock pods each sit on their own /64 veth subnet. DAD on eth0 only sees the host peer, no cross-node L2. With the IP on lo, the pod kernel doesn't reply to NDP solicits arriving on eth0 (Linux default: answer NDP only for addresses on the receiving interface). The host route `<ip>/128 dev flock<8hex>` causes the host to do NDP for the destination on the veth; pod ignores; packet drops silently between forwarding decision and transmit. Symptom: v4 anycast works (proxy_arp=1 on the host veth handles ARP), v6 anycast doesn't. Putting on eth0 makes NDP just work. Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>