We had added an optimization that made it so we dedupe pod status updates
from the provider. This ignored two subfields that could be updated along
with status.
Because the details of subresource updating is a bit API server centric,
I wrote an envtest which checks for this behaviour.
Signed-off-by: Sargun Dhillon <sargun@sargun.me>
This is a fundamentally different API than that of the K8s workqueue
which is better suited for our needs. Specifically, we need a simple
queue which doesn't have complex features like delayed adds that
sit on "external" goroutines.
In addition, we need deep introspection into the operations of the
workqueue. Although you can get this on top of the K8s workqueue
by implementing a custom rate limiter, the problem is that
the underlying rate limiter's behaviour is still somewhat
opaque.
This basically has 100% code coverage.
If you share a ratelimiter between workqueues, it breaks.
WQ1: Starts processing item (When)
WQ1: Fails to process item (When)
WQ1: Fails to process item (When)
WQ1: Fails to process item (When)
--- At this point we've backed off a bit ---
WQ2: Starts processing item (with same key, When)
WQ2: Succeeds at processing item (Forget)
WQ1: Fails to process item (When) ---> THIS RESULTS IN AN ERROR
This results in an error because it "forgot" the previous
rate limit.
Copy/paste some more kubernetes code. This is to remove the dep on
kubernetes/kubernetes from within exec.go
See #940
Signed-off-by: Miek Gieben <miek@miek.nl>
Try to stop depending on kubernetes/kubenetes. Copy golang/expansion
into the virtual-kubelet repo. The upstream code looks super stable, so
there is little harm to copy it here.
Signed-off-by: Miek Gieben <miek@miek.nl>
This refactor is a preparation for another commit. I want to add instrumentation
around our queues. The code of how queues were handled was spread throughout
the code base, and that made adding such instrumentation nice and complicated.
This centralizes the queue management logic in queue.go, and only requires
the user to provide a (custom) rate limiter, if they want to, a name,
and a handler.
The lease code is moved into its own package to simplify testing, because
the goroutine leak tester was triggering incorrectly if other tests
were running, and it was measuring leaks from those tests.
This also identified buggy behaviour:
wq := workqueue.NewNamedRateLimitingQueue(workqueue.DefaultItemBasedRateLimiter(), "test")
wq.AddRateLimited("hi")
fmt.Printf("Added hi, len: %d\n", wq.Len())
wq.Forget("hi")
fmt.Printf("Forgot hi, len: %d\n", wq.Len())
wq.Done("hi")
fmt.Printf("Done hi, len: %d\n", wq.Len())
---
Prints all 0s because event non-delayed items are delayed. If you call Add
directly, then the last line prints a len of 2.
// Workqueue docs:
// Forget indicates that an item is finished being retried. Doesn't matter whether it's for perm failing
// or for success, we'll stop the rate limiter from tracking it. This only clears the `rateLimiter`, you
// still have to call `Done` on the queue.
^----- Even this seems untrue
This refactors the v1 lease controller. It makes two functional differences
to the lease controller:
* It no longer ties lease updates to node pings or node status updates
* There is no fallback mechanism to status updates
This also moves vk_envtest, allowing for future brown-box testing of the
lease controller with envtest
As described in the issue, if the following sequence happens, we fail to properly
update the pod status in api server:
1. Create pod in k8s
2. Provider creates the pod and syncs its status back
3. Pod in k8s ready/running, all fine
4. Virtual kubelet fails to update node status for some time for whatever reason (e.g. network connectivity issues)
5. Virtual node marked as NotReady with message: Kubelet stopped posting node status
6. kube-controller-manager of k8s, goes and marks all pods as Ready = false:
7. Virtual kubelet never sync's status of pod in provider back to k8s
This uses gobin in the Makefile for golint. Gobin allows for easier
pinning of dependencies that are project specific, as in the actual
gobin command invocation you can specify the version.
We were having issues with golint not properly reporting declaration of functions
without proper documentation (comments). This is due to a config with golangci.
See: https://github.com/golangci/golangci-lint/issues/456
