Chapter 8: can't deploy echo-server due to "input/output error"

$ k describe pod tester-echo-server-79f4957797-pvjrr

Events:
  Type     Reason     Age                From               Message
  ----     ------     ----               ----               -------
  Normal   Scheduled  41s                default-scheduler  Successfully assigned default/tester-echo-server-79f4957797-pvjrr to ubuntu-w
  Normal   Pulled     17s (x3 over 40s)  kubelet            Container image "ealen/echo-server:0.6.0" already present on machine
  Normal   Created    17s (x3 over 40s)  kubelet            Created container echo-server
  Normal   Started    17s (x3 over 39s)  kubelet            Started container echo-server
  Warning  BackOff    11s (x4 over 37s)  kubelet            Back-off restarting failed container echo-server in pod tester-echo-server-79f4957797-pvjrr_default(599d903c-e9e3-4ead-b29a-ef74f444c4da)
 

btw further in the chapter, Apache deployment works fine. So, in principle it is not a blocker, but I want to know how to troubleshoot such problems in real life. E.g. do the same deployment but instead of starting Node, just open a shell and try starting Node manually? but also disable readiness&liveness probes, so that K8S doesn't restart the container while I'm inside?

I can't exec into a dead pod, that's the problem

$ k exec -it tester-echo-server-79f4957797-scmdv -- /bin/sh
error: Internal error occurred: unable to upgrade connection: container not found ("echo-server")

ChatGPT advises to export the the pod definition to YAML, replace the entrypoint with smth approx.command: [/bin/sh -c sleep] and run a new pod with the patched definition, but:

• this is way too cumbersome, I can't imagine DevOps people doing this on production systems on a regular basis
• it doesn't work anyway: exec /bin/sh: exec format error