Automatic merge from submit-queue (batch tested with PRs 48976, 49474, 40050, 49426, 49430)
Use presence of kubeconfig file to toggle standalone mode
Fixes#40049
```release-note
The deprecated --api-servers flag has been removed. Use --kubeconfig to provide API server connection information instead. The --require-kubeconfig flag is now deprecated. The default kubeconfig path is also deprecated. Both --require-kubeconfig and the default kubeconfig path will be removed in Kubernetes v1.10.0.
```
/cc @kubernetes/sig-cluster-lifecycle-misc @kubernetes/sig-node-misc
Automatic merge from submit-queue (batch tested with PRs 48976, 49474, 40050, 49426, 49430)
Remove duplicated import and wrong alias name of api package
**What this PR does / why we need it**:
**Which issue this PR fixes**: fixes#48975
**Special notes for your reviewer**:
/assign @caesarxuchao
**Release note**:
```release-note
NONE
```
Automatic merge from submit-queue
Remove flags low-diskspace-threshold-mb and outofdisk-transition-frequency
issue: #48843
This removes two flags replaced by the eviction manager. These have been depreciated for two releases, which I believe correctly follows the kubernetes depreciation guidelines.
```release-note
Remove depreciated flags: --low-diskspace-threshold-mb and --outofdisk-transition-frequency, which are replaced by --eviction-hard
```
cc @mtaufen since I am changing kubelet flags
cc @vishh @derekwaynecarr
/sig node
Replaces use of --api-servers with --kubeconfig in Kubelet args across
the turnup scripts. In many cases this involves generating a kubeconfig
file for the Kubelet and placing it in the correct location on the node.
Automatic merge from submit-queue (batch tested with PRs 48981, 47316, 49180)
Added golint check for pkg/kubelet.
**What this PR does / why we need it**:
Added golint check for pkg/kubelet, and make golint happy.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes#47315
**Release note**:
```release-note-none
```
Automatic merge from submit-queue (batch tested with PRs 47694, 47772, 47783, 47803, 47673)
Make different container runtimes constant
Make different container runtimes constant to avoid hardcode
**Release note**:
```release-note
NONE
```
Use shared informers instead of creating local controllers/reflectors
for the proxy's endpoints and service configs. This allows downstream
integrators to pass in preexisting shared informers to save on memory &
cpu usage.
This also enables the cache mutation detector for kube-proxy for those
presubmit jobs that already turn it on.
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
```
Depending on an exact cluster setup multiple dns may make sense.
Comma-seperated lists of DNS server are quite common as DNS servers
are always plain IPs.
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