* Starting NFS kernel daemon [fail]

Question

Hi I follow the https://help.ubuntu.com/community/SettingUpNFSHowTo guid to install nfs server on ubuntu 12.04 64 bit server, but when I tried to start the server I get

ubuntu# service nfs-kernel-server restart
 * Stopping NFS kernel daemon`                                            [ OK ] 
 * Unexporting directories for NFS kernel daemon...                      [ OK ] 
 * Exporting directories for NFS kernel daemon...                        [ OK ] 
 * Starting NFS kernel daemon [fail]

I want to see why it fail but I can`t find any log?

1. where are the nfs server logs?

2. Is there something I am missing here?

I find the error logs in /var/syslog

thanks to the comments now I see the folowing errors:

Jan  6 18:23:46 ip- kernel: [9107084.728144] NFSD: Using /var/lib/nfs/v4recovery as the NFSv4 state recovery directory
Jan  6 18:23:46 ip- kernel: [9107084.728166] NFSD: starting 90-second grace period
Jan  6 18:23:46 ip- rpc.svcgssd[6526]: ERROR: GSS-API: error in gss_acquire_cred(): GSS_S_FAILURE (Unspecified GSS failure.  Minor code may provide more information) - 
Jan  6 18:23:46 ip- rpc.svcgssd[6526]: unable to obtain root (machine) credentials
Jan  6 18:23:46 ip- rpc.svcgssd[6526]: do you have a keytab entry for nfs/<your.host>@<YOUR.REALM> in /etc/krb5.keytab?

What is keytab? why there in nothing about in in the official ubuntu guide ?

Answer 1

The only problem is that nfs-kernel-server not started because I was trying to run it as root, when I switch to other user and used sudo it started.