Thread by @danielbryantuk

My top 8 commands and tools for debugging applications running on @kubernetesio 🧵👇

A good first step is viewing the app's pods and associated logs (potentially targeting a specific container) looking for obvious crashes

$ kubectl get pods -n my-namespace

$ kubectl logs my-pod -c my-container

More info -> kubernetes.io/docs/reference…

If a container gets stuck in a crash-loop-backoff, use the `logs --previous` flag

$ kubectl logs my-pod -c my-container --previous

`kubectl port-forwarding` can be useful, whether it's to check if an app is responding or to expose a remote dashboard locally (I frequently use port-forwards to look at the Argo CD dashboard!)

$ kubectl port-forward my-pod 8080:8080

More info -> kubernetes.io/docs/tasks/acc…

When I need more flexibility to poke around the cluster network, I use the @CloudNativeFdn Telepresence tool to "put my laptop in the cluster"

$ telepresence connect
$ curl my-service.my-namespace:port/path

More info -> getambassador.io/docs/teleprese…

(I'm a committer on this project)

If you want to spin up a service locally and run and debug it like it was in the cluster, Telepresence helps here too (and can route remote traffic, volumes, and envs locally)

$ telepresence intercept my-service --port XX --mount=/tmp/

More info -> getambassador.io/docs/teleprese…

If all else fails, and you're not using distroless containers then `kubectl exec` can be useful to poke around in the container in the cluster (but remember, this is like SSHing into prod!)

$ kubectl exec my-pod -c my-container -- /bin/sh

More info -> kubernetes.io/docs/tasks/deb…

I'm increasingly interested in using ephemeral containers (in beta) to debug apps, especially when running distroless containers

$ kubectl debug -it ephemeral-demo --image=busybox --target=ephemeral-demo

More info -> kubernetes.io/docs/tasks/deb…

And that's it for this thread! What are some of your favourite Kubernetes debugging tips and tools? 🛠️