Normally the scheduler shouldn't schedule when there is a taint, but perhaps it
didn't know yet.
The TestEviction/update test covered this, but only failed under the right
timing conditions. The new event handler test case covers it reliably.
Events get recorded in the apiserver asynchronously, so even if the test knows
that the event has been evicted because the pod is deleted, it still has to
also check for the event to be recorded.
This caused a flake in the "Consistently" check of events.
There was one error path that led to a "controller has shut down" log
message. Other errors caused different log entries or are so unlikely (event
handler registration failure!) that they weren't checked at all.
It's clearer to let Run return an error in all cases and then log the
"controller has shut down" error at the call site. This also enables tests to
mark themselves as failed, should that ever happen.
In tests it is sometimes unavoidable to use the Prometheus types directly,
for example when writing a custom gatherer which needs to normalize data
before testing it. device_taint_eviction_test.go does this to strip
out unpredictable data in a histogram.
With type aliases in a package that is explicitly meant for tests we
can avoid adding exceptions for such tests to the global exception list.
The controller is derived from the node taint eviction controller.
In contrast to that controller it tracks the UID of pods to prevent
deleting the wrong pod when it got replaced.
This is a verbatim copy of the current pkg/controller/taintseviction code,
revision fc268ecd09 (v1.33.0 plus one commit),
minus the TimedWorker helper.
The intent is to modify the code such that it enforces eviction of pods which
use tainted devices.
