Every now and then (especially after upgrades) I see an error like:
020-07-24 19:29:42+00:00 [Warning] error killing pod: failed to "KillPodSandbox" for "0a6f9721-b383-49be-9229-52fca881189d" with KillPodSandboxError: "rpc error: code = Unknown desc = networkPlugin cni failed to teardown pod \"jupyter--42-53torm-5f-28-57-4d-46-29_prod\" network: WorkloadEndpoint.crd.projectcalico.org \"WorkloadEndpoint(prod/paws--k8s--worker--5-k8s-jupyter----42--53torm--5f--28--57--4d--46--29-eth0)\" not found"
Everything recovers and it keeps moving. However, this could be a race-condition/bug in calico or similar. It is typical that the solutions involve upgrading k8s CNI, calico or similar. It isn't a fatal error, but it is ugly to see and then have to wait for it to figure things out.