This replaces the klog formatting and message routing with a simpler
implementation that uses less code. The main difference is that we skip the
entire unused message routing.
Instead, the same split output streams as for JSON gets implemented in the
io.Writer implementation that gets passed to the textlogger.
Rate limitter.go file is a generic file implementing
grpc Limiter interface. This file can be reuse by other gRPC
API not only by podresource.
Change-Id: I905a46b5b605fbb175eb9ad6c15019ffdc7f2563
Add and use more facilities to the *internal* podresources client.
Checking e2e test runs, we have quite some
```
rpc error: code = Unavailable desc = connection error: desc = "transport: Error while dialing: dial unix /var/lib/kubelet/pod-resources/kubelet.sock: connect: connection refused": rpc error: code = Unavailable desc = connection error: desc = "transport: Error while dialing: dial unix /var/lib/kubelet/pod-resources/kubelet.sock: connect: connection refused"
```
This is likely caused by kubelet restarts, which we do plenty in e2e tests,
combined with the fact gRPC does lazy connection AND we don't really
check the errors in client code - we just bubble them up.
While it's arguably bad we don't check properly error codes, it's also
true that in the main case, e2e tests, the functions should just never
fail besides few well known cases, we're connecting over a
super-reliable unix domain socket after all.
So, we centralize the fix adding a function (alongside with minor
cleanups) which wants to trigger and ensure the connection happens,
localizing the changes just here. The main advantage is this approach
is opt-in, composable, and doesn't leak gRPC details into the client
code.
Signed-off-by: Francesco Romani <fromani@redhat.com>
This was making my eyes bleed as I read over code.
I used the following in vim. I made them up on the fly, but they seemed
to pass manual inspection.
:g/},\n\s*{$/s//}, {/
:w
:g/{$\n\s*{$/s//{{/
:w
:g/^\(\s*\)},\n\1},$/s//}},/
:w
:g/^\(\s*\)},$\n\1}$/s//}}/
:w
To enable rate limiting, needed for GA graduation,
we need to pass more parameters to the already crowded
`ListenAndServePodresources` function.
To tidy up a bit, pack the parameters in a helper struct,
with no intended changes in behavior.
Signed-off-by: Francesco Romani <fromani@redhat.com>
Added EnableNodeLogQuery field to kubelet/apis/config/types.go and
staging/src/k8s.io/kubelet/config/v1beta1/types.go, then executed.
`hack/update-codegen.sh`.
This new field will default to off and will need to be explicitly
enabled in addition to the NodeLogQuery gate to use the feature.
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.
