add integration tests to verify the behaviour of the endpoints
and endpointslices controller with dual stack services.
Since services can be single or dual stack, endpoints should be
generated for each IP family in the endpoint slice controller.
The legacy endpoint controller only will generate endpoints
in the first IP family configured in the service.
integration fix
The main goal was to cover retrieval of a PVC from the apiserver when
it isn't known yet. This is achieved by adding PVCs and (for the sake
of completeness) PVs to the reactor, but not the controller, when a
special annotation is set. The approach with a special annotation was
chosen because it doesn't affect other tests.
The other test cases were added while checking the existing tests
because (at least at first glance) the situations seemed to be not
covered.
Generally try to waive away folks who see a particular event stream
and feel tempted to extrapolate and build tooling that expects the
same underlying resource transition chain to continue to produce a
similar event stream as the underlying components evolve and are
updated. New controllers should not be constrained to be
backwards-compatible with previous versions with regard to Event
emission. This is distinct from the Event type itself, which has the
usual Kubernetes-API compatibility commitments for versioned types.
The EventTTL default has been 1h since 7e258b85bd (Reduce TTL for
events in etcd from 48hrs to 1hr, 2015-03-11, #5315), and remains so
today:
$ git --no-pager log -1 --format='%h %s' origin/master
8e5c02255c Merge pull request #90942 from ii/ii-create-pod%2Bpodstatus-resource-lifecycle-test
$ git --no-pager grep EventTTL: 8e5c02255c cmd/kube-apiserver/app/options/options.go
8e5c02255cc:cmd/kube-apiserver/app/options/options.go: EventTTL: 1 * time.Hour,
In this space [1,2]:
To avoid filling up master's disk, a retention policy is enforced:
events are removed one hour after the last occurrence. To provide
longer history and aggregation capabilities, a third party solution
should be installed to capture events.
...
Note: It is not guaranteed that all events happening in a cluster
will be exported to Stackdriver. One possible scenario when events
will not be exported is when event exporter is not running
(e.g. during restart or upgrade). In most cases it's fine to use
events for purposes like setting up metrics and alerts, but you
should be aware of the potential inaccuracy.
...
To prevent disturbing your workloads, event exporter does not have
resources set and is in the best effort QOS class, which means that
it will be the first to be killed in the case of resource
starvation.
Although that's talking more about export from etcd -> external
storage, and not about cluster components submitting events to etcd.
[1]: https://kubernetes.io/docs/tasks/debug-application-cluster/events-stackdriver/
[2]: https://github.com/kubernetes/website/pull/4155/files#diff-d8eb69c5436aa38b396d4f3ed75e4792R10
As part of externalizing this function to the k8s.io/component-helpers repo,
this commit simplifies the function signature and makes its 2 helpers private
(nodeSelectorRequirementsAsSelector and nodeSelectorRequirementsAsFieldSelector).
Normally, the PV controller knows about the PVC that triggers the
creation of a PV before it sees the PV, because the PV controller must
set the volume.beta.kubernetes.io/storage-provisioner annotation that
tells an external provisioner to create the PV.
When restarting, the PV controller first syncs its caches, so that
case is also covered.
However, the creator of a PVC might decided to set that annotation
itself to speed up volume creation. While unusual, it's not forbidden
and thus part of the external Kubernetes API. Whether it makes sense
depends on the intentions of the user.
When that is done and there is heavy load, an external provisioner
might see the PVC and create a PV before the PV controller sees the
PVC. If the PV controller then encounters the PV before the PVC, it
incorrectly concludes that the PV needs to be deleted instead of being
bound.
The same issue occurred earlier for external binding and the existing
code for looking up a PVC in the cache or in the apiserver solves the
issue also for volume provisioning, it just needs to be enabled also
for PVs without the pv.kubernetes.io/bound-by-controller annotation.
