Diagnosing NFSv4 Authentication Issues

I’ve got a couple of NFSv4 shares (with Kerberos authentication). Most of the time they work quite well, but when there’s an issue they can be a pain to fix.

I put this down to them being quite opaque as far as internal operations and error messages go – I can tell it isn’t working but can’t easily see the details of what’s going on. I generally just resort to checking the bread and butter issues (clock sync, keytabs correctly installed, etc) and muddling through.

So I thought I’d throw this question out there: When NFS/Kerberos authentication is failing, what is a good way to get more visibility on what’s going on and understanding the root cause of the problem.