Adds tests for the federated service watcher that exercise having remote and local clusters join and leave a federated service and ensuring that the correct proxy API updates are emitted.
Signed-off-by: Alex Leong <alex@buoyant.io>
Adds support for remote discovery to the destination controller.
When the destination controller gets a `Get` request for a Service with the `multicluster.linkerd.io/remote-discovery` label, this is an indication that the destination controller should discover the endpoints for this service from a remote cluster. The destination controller will look for a remote cluster which has been linked to it (using the `linkerd multicluster link` command) with that name. It will look at the `multicluster.linkerd.io/remote-discovery` label for the service name to look up in that cluster. It then streams back the endpoint data for that remote service.
Since we now have multiple client-go informers for the same resource types (one for the local cluster and one for each linked remote cluster) we add a `cluster` label onto the prometheus metrics for the informers and EndpointWatchers to ensure that each of these components' metrics are correctly tracked and don't overwrite each other.
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Signed-off-by: Alex Leong <alex@buoyant.io>
The GetProfile API endpoint does not behave as expected: when a profile
watch is established, the API server starts two separate profile
watches--a primary watch with the client's namespace and fallback watch
ignoring the client's namespace. These watches race to send data back to
the client. If the backup watch updates first, it may be sent to clients
before being corrected by a subsequent update. If the primary watch
updates with an empty value, the default profile may be served before
being corrected by an update to the backup watch.
From the proxy's perspective, we'd much prefer that the API provide a
single authoritative response when possible. It avoids needless
corrective work from distributing across the system on every watch
initiation.
To fix this, we modify the fallbackProfileListener to behave
predictably: it only emits updates once both its primary and fallback
listeners have been updated. This avoids emitting updates based on a
partial understanding of the cluster state.
Furthermore, the opaquePortsAdaptor is updated to avoid synthesizing a
default serviceprofile (surprising behavior) and, instead, this
defaulting logic is moved into a dedicated defaultProfileListener
helper. A dedupProfileListener is added to squelch obviously redundant
updates.
Finally, this newfound predictability allows us to simplify the API's
tests. Many of the API tests are not clear in what they test and
sometimes make assertions about the "incorrect" profile updates.
We frequently compare data structures--sometimes very large data
structures--that are difficult to compare visually. This change replaces
uses of `reflect.DeepEqual` with `deep.Equal`. `go-test`'s `deep.Equal`
returns a diff of values that are not equal.
Signed-off-by: Oliver Gould <ver@buoyant.io>
[gocritic][gc] helps to enforce some consistency and check for potential
errors. This change applies linting changes and enables gocritic via
golangci-lint.
[gc]: https://github.com/go-critic/go-critic
Signed-off-by: Oliver Gould <ver@buoyant.io>
The openAPIV3Schema validation in the ServiceProfiles CRD is very limited in what it can validate and is obviated by more sophisticated validation done by the validating admission controller. Therefore, we would like to remove the openAPIV3Schema validation to reduce the size and complexity of the CRD object.
To do so, we must also bump the version of the ServiceProfile custom resource from v1alpha1 to v1alpha2. This ensures that when the controller is upgraded, it will attempt to watch the v1alpha2 resource. If it cannot (because, for example, the controller pod started before the ServiceProfile CRD was updated and therefore the v1alpha2 version does not exist) then it will go into a crash loop backoff until it can. This essentially means that the controller will wait for the CRD to be upgraded to include v1alpha2 before it will start.
Bumping the version is necessary because if we did not, it would be possible for the controller to start before the CRD is updated (removing the validation). In this case, when the CRD is edited, the controller will lose its list watch on ServiceProfiles and will stop getting updates.
Signed-off-by: Alex Leong <alex@buoyant.io>
This change implements the DstOverrides feature of the destination profile API (aka traffic splitting).
We add a TrafficSplitWatcher to the destination service which watches for TrafficSplit resources and notifies subscribers about TrafficSplits for services that they are subscribed to. A new TrafficSplitAdaptor then merges the TrafficSplit logic into the DstOverrides field of the destination profile.
Signed-off-by: Alex Leong <alex@buoyant.io>
Alex Leong
Oliver Gould
Alejandro Pedraza
LiuDui
Zahari Dichev