Automatic merge from submit-queue (batch tested with PRs 59592, 62308, 62523, 62635, 62243). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
Separate pod priority from preemption
**What this PR does / why we need it**:
Users request to split priority and preemption feature gate so they can use priority separately.
**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes#62068
**Special notes for your reviewer**:
~~I kept use `ENABLE_POD_PRIORITY` as ENV name for gce cluster scripts for backward compatibility reason. Please let me know if other approach is preffered.~~
~~This is a potential **break change** as existing clusters will be affected, we may need to include this in 1.11 maybe?~~
TODO: update this doc https://kubernetes.io/docs/concepts/configuration/pod-priority-preemption/
[Update] Usage: in config file for scheduler:
```yaml
apiVersion: componentconfig/v1alpha1
kind: KubeSchedulerConfiguration
...
disablePreemption: true
```
**Release note**:
```release-note
Split PodPriority and PodPreemption feature gate
```
Thanks to some great sleuthing by ikruglov!
kube-controller-manager defaults --leader-elect to true. We should
do the same for kube-scheduler. kube-scheduler used to have this
set to true, but it got lost during refactoring in:
efb2bb71cd
* Deprecate the old experimental-fail-swap-on
* Add a new flag fail-swap-on and set it to true
Before this change, we would not fail when swap is on. With this
change we fail for everyone when swap is on, unless they explicitly
set --fail-swap-on to false.
Automatic merge from submit-queue (batch tested with PRs 44606, 46038)
Fix serialization of EnforceNodeAllocatable
EnforceNodeAllocatable being `nil` and `[]` are treated in different
ways by kubelet. Namely, `nil` is replaced with `[]string{"pods"}` by
the defaulting mechanism.
E.g. if you run kubelet in Docker-in-Docker environment
you may need to run it with the following options:
`--cgroups-per-qos=false --enforce-node-allocatable=`
(this corresponds to EnforceNodeAllocatable being empty array and not
null) If you then grab kubelet configuration via /configz and try to
reuse it for dynamic kubelet config, kubelet will think that
EnforceNodeAllocatable is null, failing to run in the
Docker-in-Docker environment.
Encountered this while updating Virtlet for Kubernetes 1.6
(the dev environment is based on kubeadm-dind-cluster)
Automatic merge from submit-queue (batch tested with PRs 45953, 45889)
Add /metrics and profiling handlers to kube-proxy
Also expose "syncProxyRules latency" as a prometheus metrics.
Fix https://github.com/kubernetes/kubernetes/issues/45876
EnforceNodeAllocatable being `nil` and `[]` are treated in different
ways by kubelet. Namely, `nil` is replaced with `[]string{"pods"}` by
the defaulting mechanism.
E.g. if you run kubelet in Docker-in-Docker environment
you may need to run it with the following options:
`--cgroups-per-qos=false --enforce-node-allocatable=`
(this corresponds to EnforceNodeAllocatable being empty array and not
null) If you then grab kubelet configuration via /configz and try to
reuse it for dynamic kubelet config, kubelet will think that
EnforceNodeAllocatable is null, failing to run in the
Docker-in-Docker environment.
Encountered this while updating Virtlet for Kubernetes 1.6
(the dev environment is based on kubeadm-dind-cluster)
Automatic merge from submit-queue
Enable shared PID namespace by default for docker pods
**What this PR does / why we need it**: This PR enables PID namespace sharing for docker pods by default, bringing the behavior of docker in line with the other CRI runtimes when used with docker >= 1.13.1.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: ref #1615
**Special notes for your reviewer**: cc @dchen1107 @yujuhong
**Release note**:
```release-note
Kubernetes now shares a single PID namespace among all containers in a pod when running with docker >= 1.13.1. This means processes can now signal processes in other containers in a pod, but it also means that the `kubectl exec {pod} kill 1` pattern will cause the pod to be restarted rather than a single container.
```
The exported or public functions requires a doc comment to pass golint.
This commit has changes of conversion generated code. The actual doc
changes are added into a separate commit for a clean review.
Automatic merge from submit-queue
Add dockershim only mode
This PR added a `experimental-dockershim` hidden flag in kubelet to run dockershim only.
We introduce this flag mainly for cri validation test. In the future we should compile dockershim into another binary.
@yujuhong @feiskyer @xlgao-zju
/cc @kubernetes/sig-node-pr-reviews
Kubelet flags are not necessarily appropriate for the KubeletConfiguration
object. For example, this PR also removes HostnameOverride and NodeIP
from KubeletConfiguration. This is a preleminary step to enabling Nodes
to share configurations, as part of the dynamic Kubelet configuration
feature (#29459). Fields that must be unique for each node inhibit
sharing, because their values, by definition, cannot be shared.
Automatic merge from submit-queue
Allow multipe DNS servers as comma-seperated argument for kubelet --dns
This PR explores how kubectls "--dns" could be extended to specify multiple DNS servers for in-cluster PODs. Testing on the local libvirt-coreos cluster shows that multiple DNS server are injected without issues.
Specifying multiple DNS servers increases resilience against
- Packet drops
- Single server failure
I am debugging services that do 50+ DNS requests for a single incoming interactive request, thus highly increase the chance of a slowdown (+5s) due to a single packet drop. Switching to two DNS servers will reduce the impact of the issues (roughly +1s on glibc, 0s on musl, error-rate goes down to error-rate^2).
Note that there is no need to change any runtime related code as far as I know. In the case of "default" dns the /etc/resolv.conf is parsed and multiple DNS server are send to the backend anyway. This only adds the same capability for the clusterFirst case.
I've heard from @thockin that multiple DNS entries are somehow considered. I've no idea what was considered, though. This is what I would like to see for our production use, though.
```release-note
NONE
```
This change makes kubelet to use the CRI implementation by default,
unless the users opt out explicitly by using --enable-cri=false.
For the rkt integration, the --enable-cri flag will have no effect
since rktnetes does not use CRI.
Also, mark the original --experimental-cri flag hidden and deprecated,
so that we can remove it in the next release.
Clayton Coleman