* 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()
Currently, all the plugins are run in a sequence.
No plugin executes evictions in parallel within.
Yet, there's no guarantee a future plugin (e.g. a custom one)
will not attemp to evict pods in parallel.
When checking for node limit getting exceeded the pod eviction
never fails. Thus, ignoring the metric reporting when a pod fails
to be evicted due to node limit constrains.
The error also allows plugin to react on other limits getting
exceeded. E.g. the limit on the number of pods evicted per namespace.
Currently, the pod evictor is created during each descheduling cycle
to reset the internal counters and the fake client (in case a dry run is
configured). Instead, create the pod evictor once and reset only what's
needed. So later on the pod evictor can be extended with e.g. a cache
keeping the track of eviction requests that are still in progress and
required more than a single descheduling cycle to complete.
* Check if Pod matches inter-pod anti-affinity of other pod on node as part of NodeFit()
* Add unit tests for checking inter-pod anti-affinity match in NodeFit()
* Export setPodAntiAffinity() helper func to test utils
* Add docs for inter-pod anti-affinity in README
* Refactor logic for inter-pod anti-affinity to use in multiple pkgs
* Move logic for finding match between pods with antiaffinity out of framework to reuse in other pkgs
* Move interpod antiaffinity funcs to pkg/utils/predicates.go
* Add unit tests for inter-pod anti-affinity check
* Test logic in GroupByNodeName
* Test NodeFit() case where pods matches inter-pod anti-affinity
* Test for inter-pod anti-affinity pods match terms, have label selector
* NodeFit inter-pod anti-affinity check returns early if affinity spec not set
