cmd/{containerboot,k8s-operator},kube: add preshutdown hook for egress PG proxies
This change is part of work towards minimizing downtime during update
rollouts of egress ProxyGroup replicas.
This change:
- updates the containerboot health check logic to return Pod IP in headers,
if set
- always runs the health check for egress PG proxies
- updates ClusterIP Services created for PG egress endpoints to include
the health check endpoint
- implements preshutdown endpoint in proxies. The preshutdown endpoint
logic waits till, for all currently configured egress services, the ClusterIP
Service health check endpoint is no longer returned by the shutting-down Pod
(by looking at the new Pod IP header).
- ensures that kubelet is configured to call the preshutdown endpoint
This reduces the possibility that, as replicas are terminated during an update,
a replica gets terminated to which cluster traffic is still being routed via
the ClusterIP Service because kube proxy has not yet updated routig rules.
This is not a perfect check as in practice, it only checks that the kube
proxy on the node on which the proxy runs has updated rules. However, overall
this might be good enough.
The preshutdown logic is disabled if users have configured a custom health check
port via TS_LOCAL_ADDR_PORT env var. This change throws a warnign if so and in
future setting of that env var for operator proxies might be disallowed (as users
shouldn't need to configure this for a Pod directly).
This is backwards compatible with earlier proxy versions.
Updates tailscale/tailscale#14326
Signed-off-by: Irbe Krumina <irbe@tailscale.com>
Ensure that .status.podIPs is used to select Pod's IP
in all reconcilers.
Updates tailscale/tailscale#13406
Signed-off-by: Irbe Krumina <irbe@tailscale.com>
Currently egress Services for ProxyGroup only work for Pods and Services
with IPv4 addresses. Ensure that it works on dual stack clusters by reading
proxy Pod's IP from the .status.podIPs list that always contains both
IPv4 and IPv6 address (if the Pod has them) rather than .status.podIP that
could contain IPv6 only for a dual stack cluster.
Updates tailscale/tailscale#13406
Signed-off-by: Irbe Krumina <irbe@tailscale.com>
Adds a new reconciler that reconciles ExternalName Services that define a
tailnet target that should be exposed to cluster workloads on a ProxyGroup's
proxies.
The reconciler ensures that for each such service, the config mounted to
the proxies is updated with the tailnet target definition and that
and EndpointSlice and ClusterIP Service are created for the service.
Adds a new reconciler that ensures that as proxy Pods become ready to route
traffic to a tailnet target, the EndpointSlice for the target is updated
with the Pods' endpoints.
Updates tailscale/tailscale#13406
Signed-off-by: Irbe Krumina <irbe@tailscale.com>
