Fixes https://github.com/linkerd/linkerd2/issues/2800#issuecomment-513740498
When the Linkerd proxy sends a query for a Kubernetes external name service to the destination service, the destination service returns `NoEndpoints: exists=false` because an external name service has no endpoints resource. Due to a change in the proxy's fallback logic, this no longer causes the proxy to fallback to either DNS or SO_ORIG_DST and instead fails the request. The net effect is that Linkerd fails all requests to external name services.
We change the destination service to instead return `InvalidArgument` for external name services. This causes the proxy to fallback to SO_ORIG_DST instead of failing the request.
Signed-off-by: Alex Leong <alex@buoyant.io>
The destination service's endpoints watcher assumed every `Endpoints`
object contained a `TargetRef`. This field is optional, and in cases
such as the default `ep/kubernetes` object, `TargetRef` is nil, causing
a nil pointer dereference.
Fix endpoints watcher to check for `TargetRef` prior to dereferencing.
Signed-off-by: Andrew Seigner <siggy@buoyant.io>
We add support for looking up individual pods in a stateful set with the destination service. This allows Linkerd to correctly proxy requests which address individual pods. The authority structure for such a request is `<pod-name>.<service>.<namespace>.svc.cluster.local:<port>`.
Fixes#2266
Signed-off-by: Alex Leong <alex@buoyant.io>
To give better visibility into the inner workings of the kubernetes watchers in the destination service, we add some prometheus metrics.
Signed-off-by: Alex Leong <alex@buoyant.io>
* Have `GetOwnerKindAndName` be able to skip the cache
Refactored `GetOwnerKindAndName` so it can optionally skip the
shared informer cache and instead hit the k8s API directly.
Useful for the proxy injector, when the pod's replicaset got just
created and might not be in ready in the cache yet.
Fixes#2738
Signed-off-by: Alejandro Pedraza <alejandro@buoyant.io>
This is a major refactor of the destination service. The goals of this refactor are to simplify the code for improved maintainability. In particular:
* Remove the "resolver" interfaces. These were a holdover from when our decision tree was more complex about how to handle different kinds of authorities. The current implementation only accepts fully qualified kubernetes service names and thus this was an unnecessary level of indirection.
* Moved the endpoints and profile watchers into their own package for a more clear separation of concerns. These watchers deal only in Kubernetes primitives and are agnostic to how they are used. This allows a cleaner layering when we use them from our gRPC service.
* Renamed the "listener" types to "translator" to make it more clear that the function of these structs is to translate kubernetes updates from the watcher to gRPC messages.
Signed-off-by: Alex Leong <alex@buoyant.io>
Alex Leong
Andrew Seigner
Alejandro Pedraza