metal-stack uses frr and BGP for routing-to-the-host. If a calico interface / pod IP gets added or removed to the kernel routing table, frr announces or removes the according BGP route.
There is an open issue with frr, that sometimes - in rare cases - frr misses these route-changes: FRRouting/frr#7299 and the BGP routing tables differs from kernel routing table, leading to unreachable pods.
Since all pod IPs on a node are from the same podCIDR anyway, there is no need for host-routes for every pod. It's sufficient enough to simply route the whole node.podCIDR to that node.
node-init reads node.spec.podCIDR and sets a route to dev lo0. This results in a BGP route for this podCIDR to that node and therefore mitigates the issue with missing podIP routes.
Usage:
node-init [command]
Available Commands:
help Help about any command
init init node networking
Flags:
-h, --help help for node-init
Use "node-init [command] --help" for more information about a command.
kubectl apply -f deploy/node-init.yaml