mount -t nfs4 fails, but mount -t nfs succeeds [SOLVED]

[Jonathan Ryshpan]

On Fri, 2012-04-27 at 16:10 +0800, Ed Greshko wrote:
> First, it may be helpful for you to post the contents of your
> server's /etc/exports
> and /etc/fstab.

Here they are.  /etc/exports is much chewed up by many experiments; this
is its latest incarnation.  /etc/fstab follows.
        $ more exports
        /               amito(rw,fsid=root,no_root_squash)
        # /home/jonrysh amito(rw,no_root_squash)
        # /var          amito(rw,no_root_squash)
        # /nfs4exports  192.168.0.0/24(ro,root_squash,no_subtree_check,fsid=0) 
        
        # /nfs4exports         192.168.0.0/24(ro,fsid=root,insecure,no_subtree_check,no_root_squash) 
        # /nfs4exports/home    192.168.0.0/24(rw,nohide,insecure,no_subtree_check,no_root_squash)
        # /nfs4exports/sbin    192.168.0.0/24(rw,nohide,insecure,no_subtree_check,no_root_squash)
        
        # /nfs4exports         192.168.2.5(ro,fsid=root,insecure,no_subtree_check,no_root_squash) 
        # /nfs4exports/home    192.168.2.5(rw,nohide,insecure,no_subtree_check,no_root_squash)
        # /nfs4exports/sbin    192.168.2.5(rw,nohide,insecure,no_subtree_check,no_root_squash)
        
        $ more fstab
        # /etc/fstab
        # Created by anaconda on Fri Mar 30 11:08:48 2012
        #
        # Accessible filesystems, by reference, are maintained under '/dev/disk'
        # See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
        #
        UUID=2df88f7e-a779-401a-8e47-0c32d500b5af /               ext4    defaults        1 1
        UUID=d64559f2-2e25-4a96-a937-bbe06516ab2c /boot           ext4    defaults        1 2
        UUID=2d7ec72f-f9af-4ec8-aff0-03d07ef30b73 /var            ext4    defaults        1 2
        UUID=5fb1efb6-3e12-437f-a12e-b60cb622d001 swap            swap    defaults        0 0

> Second, have you modified your idmap.conf such that you have identical
> Domain =
> lines?  Note that after modification the nfs-idmap.service needs to be
> restarted. 

You must mean /etc/idmapd.conf .  This file is untouched on both client
and server.  It has a single "Domain = ..." line, which is commented
out.  I'm not sure what it should be identical to.  The value of this 
variable should be the local domain name, which is null.
        $ dnsdomainname
        $ hostname --fqdn
        amito

Thanks - jon