Automatic merge from submit-queue (batch tested with PRs 50932, 49610, 51312, 51415, 50705)
Implement StatsProvider interface using cadvisor
Ref: https://github.com/kubernetes/kubernetes/issues/46984
- This PR changes the `StatsProvider` interface in `pkg/kubelet/server/stats` so that it can provide container stats from either cadvisor or CRI, and the summary API can consume the stats without knowing how they are provided.
- The `StatsProvider` struct in the newly added package `pkg/kubelet/stats` implements part of the `StatsProvider` interface in `pkg/kubelet/server/stats`.
- In `pkg/kubelet/stats`,
- `stats_provider.go`: implements the node level stats and provides the entry point for this package.
- `cadvisor_stats_provider.go`: implements the container level stats using cadvisor.
- `cri_stats_provider.go`: implements the container level stats using CRI.
- `helper.go`: utility functions shared by the above three components.
- There should be no user visible behaviors change in this PR.
- A follow up PR will implement the StatsProvider interface using CRI.
**Release note**:
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/assign @yujuhong
/assign @WIZARD-CXY
c27cdb11a9