Refactor the kube-scheduler configuration API, command setup, and server
setup according to the guidelines established in #32215 and using the
kube-proxy refactor (#34727) as a model of a well factored component
adhering to said guidelines.
* Config API: clarify meaning and use of algorithm source by replacing
modality derived from bools and string emptiness checks with an explicit
AlgorithmSource type hierarchy.
* Config API: consolidate client connection config with common structs.
* Config API: split and simplify healthz/metrics server configuration.
* Config API: clarify leader election configuration.
* Config API: improve defaulting.
* CLI: deprecate all flags except `--config`.
* CLI: port all flags to new config API.
* CLI: refactor to match kube-proxy Cobra command style.
* Server: refactor away configurator.go to clarify application wiring.
* Server: refactor to more clearly separate wiring/setup from running.
Fixes#52428.
Automatic merge from submit-queue (batch tested with PRs 47961, 46276)
Remove duplicate error message output in hyperkube.
**What this PR does / why we need it**:
Currently hyperkube binary will always print duplicate messages if fatal error occurs:
```
$ ./kubelet # run without permission
I0523 08:38:02.642638 25701 feature_gate.go:144] feature gates: map[]
W0523 08:38:02.642827 25701 server.go:472] No API client: no api servers specified
Error: failed to run Kubelet: error reading /var/run/kubernetes/kubelet.key, certificate and key must be supplied as a pair
Error: failed to run Kubelet: error reading /var/run/kubernetes/kubelet.key, certificate and key must be supplied as a pair
```
This is due to RunToExit will print out the error which Run has just printed. https://github.com/kubernetes/kubernetes/blob/8bee44b/cmd/hyperkube/hyperkube.go#L178-L189
This was introduced in following commit for adding GOMAXPROCS calls.
1e679f0069
The following commit removes GOMAXPROCS calls, but did not remove the corresponding error output line.
88ea80b572
**Which issue this PR fixes**
**Special notes for your reviewer**:
**Release note**:
Automatic merge from submit-queue (batch tested with PRs 45514, 45635)
hyperkube_test should not depend on number of spaces.
From #45524.
Apparently adding a long flag to kube-controller-manager breaks the hyperkube unit tests, because they depend on number of spaces :)
**Release note**:
```release-note
NONE
```
Automatic merge from submit-queue
Update github.com/spf13/pflag and github.com/spf13/cobra
Update github.com/spf13/pflag and github.com/spf13/cobra
Update:
github.com/spf13/cobra to f62e98d28ab7ad31d707ba837a966378465c7b57
github.com/spf13/cobra/doc to f62e98d28ab7ad31d707ba837a966378465c7b57
github.com/spf13/pflag to 1560c1005499d61b80f865c04d39ca7505bf7f0b
Closes issue #29852
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Automatic merge from submit-queue
Cut the client repo, staging it in the main repo
Tracking issue: #28559
ref: https://github.com/kubernetes/kubernetes/pull/25978#issuecomment-232710174
This PR implements the plan a few of us came up with last week for cutting client into its own repo:
1. creating "_staging" (name is tentative) directory in the main repo, using a script to copy the client and its dependencies to this directory
2. periodically publishing the contents of this staging client to k8s.io/client-go repo
3. converting k8s components in the main repo to use the staged client. They should import the staged client as if the client were vendored. (i.e., the import line should be `import "k8s.io/client-go/<pacakge name>`). This requirement is to ease step 4.
4. In the future, removing the staging area, and vendoring the real client-go repo.
The advantage of having the staging area is that we can continuously run integration/e2e tests with the latest client repo and the latest main repo, without waiting for the client repo to be vendored back into the main repo. This staging area will exist until our test matrix is vendoring both the client and the server.
In the above plan, the tricky part is step 3. This PR achieves it by creating a symlink under ./vendor, pointing to the staging area, so packages in the main repo can refer to the client repo as if it's vendored. To prevent the godep tool from messing up the staging area, we export the staged client to GOPATH in hack/godep-save.sh so godep will think the client packages are local and won't attempt to manage ./vendor/k8s.io/client-go.
This is a POC. We'll rearrange the directory layout of the client before merge.
@thockin @lavalamp @bgrant0607 @kubernetes/sig-api-machinery
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Update:
github.com/spf13/cobra to f62e98d28ab7ad31d707ba837a966378465c7b57
github.com/spf13/cobra/doc to f62e98d28ab7ad31d707ba837a966378465c7b57
github.com/spf13/pflag to 1560c1005499d61b80f865c04d39ca7505bf7f0b
Closes issue #29852
Cole Mickens
