Previously, the scheduler created two separate list watchers. This
changes the scheduler to be able to leverage a shared informer, whether
passed in externally or spawned using the new in place method. This
removes the last use of a "special" informer in the codebase.
Allows someone wrapping the scheduler to use a shared informer if they
have more information avaliable.
Automatic merge from submit-queue
Scheduler configurator looks for a specific key in ConfigMap.Data
**What this PR does / why we need it**: Changes scheduler configurator to look for a specific key in ConfigMap.Data instead of the old logic which expected only one entry to exist in the map. The key is a constant whose value is "policy.cfg".
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #
**Special notes for your reviewer**:
**Release note**:
```release-note
```
Where possible, switch the scheduler to use generated listers and
informers. There are still some places where it probably makes more
sense to use one-off reflectors/informers (listing/watching just a
single node, listing/watching scheduled & unscheduled pods using a field
selector).
Automatic merge from submit-queue (batch tested with PRs 39538, 40188, 40357, 38214, 40195)
Decoupling scheduler creation from creation of scheduler.Config struc…
**What this PR does / why we need it**:
Adds functionality to the scheduler to initialize from an Configurator interface, rather then via a Config struct.
**Which issue this PR fixes**
Reduces coupling to `scheduler.Config` data structure format so that we can proliferate more interface driven composition of scheduler components.
Automatic merge from submit-queue (batch tested with PRs 38315, 38624, 38572, 38544)
scheduler: refactor main entry Run()
The kube-scheduler/app.Run() is the main entry of scheduler program.
It's enormous.
This PR tries to clean it up. Should be more modular and readable.
Automatic merge from submit-queue (batch tested with PRs 36263, 36755, 37357, 37222, 37524)
Add flag to enable contention profiling in scheduler.
```release-note
Add flag to enable contention profiling in scheduler.
```