this commit introduces a new customization on the existing PodsWithPVC
protection. this new customization allow users to make pods that refer
to a given storage class unevictable.
for example, to protect pods referring to `storage-class-0` and
`storage-class-1` this configuration can be used:
```yaml
apiVersion: "descheduler/v1alpha2"
kind: "DeschedulerPolicy"
profiles:
- name: ProfileName
pluginConfig:
- name: "DefaultEvictor"
args:
podProtections:
extraEnabled:
- PodsWithPVC
config:
PodsWithPVC:
protectedStorageClasses:
- name: storage-class-0
- name: storage-class-1
```
changes introduced by this pr:
1. the descheduler starts to observe persistent volume claims.
1. a new api field was introduced to allow per pod protection config.
1. rbac had to be adjusted (+persistentvolumeclaims).
* skip eviction when pod creation time is below minPodAge threshold setting
In the default initialization phase of the descheduler, add a new
constraint to not evict pods that creation time is below minPodAge
threshold.
Added value:
- Avoid crazy pod movement when the autoscaler scales up and down.
- Avoid evicting pods when they are warming up.
- Decreases the overall cost of eviction as no pod will be evicted
before doing significant amount of work.
- Guard against scheduling. Descheduling loops in situations where
the descheduler has a different node fit logic from scheduler,
like not considering topology spread constraints.
* Use *time.Duration instead of uint for MinPodAge type
* Remove '(in minutes)' from default evictor configuration table
* make fmt
* Add explicit name for Duration field
* Use Duration.String()
* use plugin registry and prepare for conersion
* Register plugins explicitly to a registry
* check interface impl instead of struc var
* setup plugins at top level
* treat plugin type combinations
* pass registry as arg of V1alpha1ToInternal
* move registry yet another level up
* check interface type separately
