kubelet: Refactor RunInContainer/ExecInContainer/PortForward.

[yifan-gu]

Replace GetKubeletDockerContainers() with GetPods().

This removes the docker specific code in further. (Now we only have one GetKubeletDockerContainers!)

I remember @dchen1107 said now each pod has its UID, so I think we can remove the podFullName part in the kubelet's interface.(correct me if I am wrong, thank you!).

@vmarmol @yujuhong

[yujuhong]

Thanks for the PR! We've made quite some progress in this direction! :)

I may be wrong, but IMO, kubelet should use UID internally, but should also support querying using pod (namespace, name) tuple in public-facing interface. As far as I know, the interface is defined here https://github.com/GoogleCloudPlatform/kubernetes/blob/master/pkg/kubelet/server.go#L99

[dchen1107]

Didn't review PR in detail yet, @yujuhong is right. UID is terrible on user friendly.

[yifan-gu]

@yujuhong Thank you for clarification! I was wondering why e2e is failing... Maybe this is related.
Just updated the PR to keep the podFullName. Running e2e again.

[vmarmol]

LGTM, will wait on your results with e2e.

One day, my dream is that we will only use UID internally (and translate full name to UID once we take it in). But it's not currently a priority.

[yifan-gu]

Just cannot finish e2e because I have a terrible network at home... Will run tomorrow morning when I arrive the company.

[yifan-gu]

@vmarmol
Got 1 failure, think it's not related: #6517

Summarizing 1 Failure:

[Fail] Cluster level logging using Elasticsearch [It] should check that logs from pods on all nodes are ingested into Elasticsearch
/go/src/github.com/GoogleCloudPlatform/kubernetes/_output/dockerized/go/src/github.com/GoogleCloudPlatform/kubernetes/test/e2e/es_cluster_logging.go:326

Ran 32 of 37 Specs in 1318.850 seconds
FAIL! -- 31 Passed | 1 Failed | 0 Pending | 5 Skipped watchEvents output: |

[satnam6502]

Pretty sure this test failure is not related since it is pointing out an unrelated issue in our system.

[vmarmol]

LGTM @yifan-gu! Merging.