Multiple expanders can now be specified, expanders now "filter to the
tied for best" instead of "selecting the best" so the output of one
expander is now fed to the input of the next. Each expander may only
be used once to disallow bad configuration. This should not be a change
in functionality as in the event of a tie the random expander is still
used.
The following things changed in scheduler and needed to be fixed:
* NodeInfo was moved to schedulerframework
* Some fields on NodeInfo are now exposed directly instead of via getters
* NodeInfo.Pods is now a list of *schedulerframework.PodInfo, not *apiv1.Pod
* SharedLister and NodeInfoLister were moved to schedulerframework
* PodLister was removed
Adds a new optional flag named `configmap` to specify the name of a configmap containing node group specs.
The configmap is polled every `scan-interval` seconds to reconfigure cluster-autoscaler dynamically at runtime.
Example usage:
```
./cluster-autoscaler --v=4 --cloud-provider=aws --skip-nodes-with-local-storage=false --logtostderr --leader-elect=false --configmap=cluster-autoscaler --logtostderr
```
The configmap would look like:
```yaml
kind: ConfigMap
apiVersion: v1
metadata:
name: cluster-autoscaler
namespace: kube-system
data:
settings: |-
{
"nodeGroups": [
{
"minSize": 1,
"maxSize": 2,
"name": "kubeawstest-nodepool1-AutoScaleWorker-1VWD4GAVG35L5"
}
]
}
```
Other notes:
* Make namespace defaults to "kube-system"
according to https://github.com/kubernetes/contrib/pull/2226#discussion_r94144267
* Trigger a full-recreate on a configuration change
according to https://github.com/kubernetes/contrib/pull/2226#issuecomment-269617410
* Introduced `autoscaler/` and moved all the dynamic/recreatable-at-runtime parts of autoscaler into there (Update: the package is now named `core` according to https://github.com/kubernetes/contrib/pull/2226#issuecomment-273071663)
* Extracted the core of CA(=`func Run()` in `main.go`) into `Autoscaler`
* `DynamicAutoscaler` is a wrapper around `Autoscaler` which achieves reconfiguration of CA by recreating an `Autoscaler` instance on a configmap change.
* Moved `scale_down*.go`, `scale_up*.go` and `utils*.go` into the `autoscaler` package accordingly because they seemed to be meant to be collocated in the same package as the core of CA (which is now implemented as `Autoscaler`)
* Moved the `createEventRecorder` func from the `main` package to the `utils/kubernetes` package to make it importable from both `main` and `autoscaler`
Evan Sheng
Ryan McNamara
Bartłomiej Wróblewski
Jakub Tużnik
Lukasz Piatkowski
Pengfei Ni
Marcin Wielgus
Yusuke Kuoka
thebigjc