Implement CRI stats for dockershim using docker stats. This enables use
of the summary api to get container metrics on Windows where CRI stats
are enabled.
Automatic merge from submit-queue (batch tested with PRs 49488, 50407, 46105, 50456, 50258)
Add UpdateContainerResources method to CRI
This is first step toward support for opinionated cpu pinning for certain guaranteed pods.
In order to do this, the kubelet needs to be able to dynamically update the cpuset at the container level, which is managed by the container runtime. Thus the kubelet needs a method to communicate over the CRI so the runtime can then modify the container cgroup.
This is used in the situation where a core is added or removed from the shared pool to become a exclusive core for a new G pod. The cpuset for all containers in the shared pool will need to be updated to add or remove that core.
Opening this up now so we can start discussion. The need for a change to the CRI might be unexpected.
@derekwaynecarr @vishh @ConnorDoyle
```release-note
NONE
```
Automatic merge from submit-queue (batch tested with PRs 45809, 46515, 46484, 46516, 45614)
CRI: add methods for container stats
**What this PR does / why we need it**:
Define methods in CRI to get container stats.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*:
Part of https://github.com/kubernetes/features/issues/290; addresses #27097
**Special notes for your reviewer**:
This PR defines the *minimum required* container metrics for the existing components to function, loosely based on the previous discussion on [core metrics](https://github.com/kubernetes/community/blob/master/contributors/design-proposals/core-metrics-pipeline.md) as well as the existing cadvisor/summary APIs.
Two new RPC calls are added to the RuntimeService: `ContainerStats` and `ListContainerStats`. The former retrieves stats for a given container, while the latter gets stats for all containers in one call.
The stats gathering time of each subsystem can vary substantially (e.g., cpu vs. disk), so even though the on-demand model preferred due to its simplicity, we’d rather give the container runtime more flexibility to determine the collection frequency for each subsystem*. As a trade-off, each piece of stats for the subsystem must contain a timestamp to let kubelet know how fresh/recent the stats are. In the future, we should also recommend a guideline for how recent the stats should be in order to ensure the reliability (e.g., eviction) and the responsiveness (e.g., autoscaling) of the kubernetes cluster.
The next step is to plumb this through kubelet so that kubelet can choose consume container stats from CRI or cadvisor.
**Alternatively, we can add calls to get stats of individual subsystems. However, kubelet does not have the complete knowledge of the runtime environment, so this would only lead to unnecessary complexity in kubelet.*
**Release note**:
```release-note
Augment CRI to support retrieving container stats from the runtime.
```
Jeff Grafton