Implement DOS prevention wiring a global rate limit for podresources
API. The goal here is not to introduce a general ratelimiting solution
for the kubelet (we need more research and discussion to get there),
but rather to prevent misuse of the API.
Known limitations:
- the rate limits value (QPS, BurstTokens) are hardcoded to
"high enough" values.
Enabling user-configuration would require more discussion
and sweeping changes to the other kubelet endpoints, so it
is postponed for now.
- the rate limiting is global. Malicious clients can starve other
clients consuming the QPS quota.
Add e2e test to exercise the flow, because the wiring itself
is mostly boilerplate and API adaptation.
b837a0c1ff