Networking probes

[aojea]

Talked with @danwinship offline, it will be nice to be able to report

• Pod network problems
• DNS cluster problems
• Services problems

It should not be hard to provide some basic plugins that provide some basic checks, if we can figure out the best way to obtain the information needed

[aojea]

/cc @danwinship
/assign @aojea

[googs1025]

We currently have some pods such as cni network plug-ins, and we also want to detect its health status.

We now use custom plugins to detect whether a specific pod is alive. Perhaps HealthChecker should also support monitoring the status of a specific pod for inspection. 🤔