Automatic merge from submit-queue (batch tested with PRs 39418, 41175, 40355, 41114, 32325)
TaintController
```release-note
This PR adds a manager to NodeController that is responsible for removing Pods from Nodes tainted with NoExecute Taints. This feature is beta (as the rest of taints) and enabled by default. It's gated by controller-manager enable-taint-manager flag.
```
Automatic merge from submit-queue (batch tested with PRs 40917, 41181, 41123, 36592, 41183)
Set all node conditions to Unknown when node is unreachable
**What this PR does / why we need it**:
Sets all node conditions to Unknown when node does not report status/unreachable
**Which issue this PR fixes**
fixes https://github.com/kubernetes/kubernetes/issues/36273
When tryUpdateNodeStatus() return err,err!=nil, but nc.kubeClient.Core().Nodes().Get() return no err, err==nil,
And we run nodeStatusUpdateRetry times, when for loop ends, err == nil, we can not print error info and run continue, so the condition judgement is wrong.
Automatic merge from submit-queue
Node controller to not force delete pods
Fixes https://github.com/kubernetes/kubernetes/issues/35145
- [x] e2e tests to test Petset, RC, Job.
- [x] Remove and cover other locations where we force-delete pods within the NodeController.
**Release note**:
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``` release-note
Node controller no longer force-deletes pods from the api-server.
* For StatefulSet (previously PetSet), this change means creation of replacement pods is blocked until old pods are definitely not running (indicated either by the kubelet returning from partitioned state, or deletion of the Node object, or deletion of the instance in the cloud provider, or force deletion of the pod from the api-server). This has the desirable outcome of "fencing" to prevent "split brain" scenarios.
* For all other existing controllers except StatefulSet , this has no effect on the ability of the controller to replace pods because the controllers do not reuse pod names (they use generate-name).
* User-written controllers that reuse names of pod objects should evaluate this change.
```
We had another bug where we confused the hostname with the NodeName.
To avoid this happening again, and to make the code more
self-documenting, we use types.NodeName (a typedef alias for string)
whenever we are referring to the Node.Name.
A tedious but mechanical commit therefore, to change all uses of the
node name to use types.NodeName
Also clean up some of the (many) places where the NodeName is referred
to as a hostname (not true on AWS), or an instanceID (not true on GCE),
etc.
