Recording Events in a Provider

[Smithx10]

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Environment summary

Provider (Triton)
Version (0...0..0.000..1)
K8s Master Info (minikube)
Install Method (go build)

Issue Details

While developing the Triton Provider I ran into a scenario where I would like to pass Events to the user. So they would appear in kubectl get events.

I looked how the regular Kubelet was doing so, and they used a recorder.

https://github.com/kubernetes/kubernetes/blob/master/pkg/kubelet/kubelet_pods.go#L594

In order for your recorder to sink events you need a *kubernetesClientset
https://github.com/virtual-kubelet/virtual-kubelet/blob/master/vkubelet/podcontroller.go#L69

I was able to create the desired behavior by passing the k8sclient that VK was using into the provider by adding the kubernetes clientset to register.
https://github.com/virtual-kubelet/virtual-kubelet/blob/master/providers/register/register.go#L13

@pires expressed concern about using the same Client as VK, and that the provider should init their own kubernetes client. I am completely fine with that, and am now wondering if we should pass kubeConfig from https://github.com/virtual-kubelet/virtual-kubelet/blob/master/cmd/root.go#L267 into register so that Providers can easily init a new client, or have them reach out themselves via the provider config https://github.com/virtual-kubelet/virtual-kubelet/blob/master/providers/mock/mock.go#L76

[pires]

I still share concerns about using the same Kubernetes client the VK uses to do its thing (track Pods, Secrets, ConfigMaps, the Node, send events). This means an option is for the VK to instantiate a second client and share listers + an event recorder the provider can use.

This aligns with what I did in systemk because VK didn't expose nothing I could use. That said, I think it's safe to say I may have all the info needed to evolve the Provider API to support this.

@cpuguy83 I think this is something that should be done soon. WDYT?

[cpuguy83]

It seems pretty tricky to do much here, because no matter what the provider is going to have to tell something that an event occurred. Why wouldn't that be a literal event recorder?

[pires]

My idea really is to provide an event recorder while making sure it's a client instance that is not used by VK, to avoid bad providers spamming events to mess w/ VK performance.

[pires]

Feel free to unsubscribe @Smithx10 but I'll keep the issue open. Thanks for reporting!