TL;DR: we want to start failing the LB HC if a node is tainted with ToBeDeletedByClusterAutoscaler.
This field might need refinement, but currently is deemed our best way of understanding if
a node is about to get deleted. We want to do this only for eTP:Cluster services.
The goal is to connection draining terminating nodes
Since kube-proxy in LocalModeNodeCIDR needs to obtain the PodCIDR
assigned to the node it watches for the Node object.
However, kube-proxy startup process requires to have these watches in
different places, that opens the possibility of having a race condition
if the same node is recreated and a different PodCIDR is assigned.
Initializing the second watch with the value obtained in the first one
allows us to detect this situation.
Change-Id: I6adeedb6914ad2afd3e0694dcab619c2a66135f8
Signed-off-by: Antonio Ojea <aojea@google.com>
Kube/proxy, in NodeCIDR local detector mode, uses the node.Spec.PodCIDRs
field to build the Services iptables rules.
The Node object depends on the kubelet, but if kube-proxy runs as a
static pods or as a standalone binary, it is not possible to guarantee
that the values obtained at bootsrap are valid, causing traffic outages.
Kube-proxy has to react on node changes to avoid this problems, it
simply restarts if detect that the node PodCIDRs have changed.
In case that the Node has been deleted, kube-proxy will only log an
error and keep working, since it may break graceful shutdowns of the
node.
