My kubernetes pods keep crashing with “CrashLoopBackOff” but I can't find any log

Question

This is what I keep getting:

[root@centos-master ~]# kubectl get pods
NAME               READY     STATUS             RESTARTS   AGE
nfs-server-h6nw8   1/1           


        

Answer 1

In my case the problem was what Steve S. mentioned:

The pod is crashing because it starts up then immediately exits, thus Kubernetes restarts and the cycle continues.

Namely I had a Java application whose main threw an exception (and something overrode the default uncaught exception handler so that nothing was logged). The solution was to put the body of main into try { ... } catch and print out the exception. Thus I could find out what was wrong and fix it.

(Another cause could be something in the app calling System.exit; you could use a custom SecurityManager with an overridden checkExit to prevent (or log the caller of) exit; see https://stackoverflow.com/a/5401319/204205.)