Unable to mount NFS on linux clients

[kaushikbr]

Hi Experts

We have a 2 node serviceguard cluster running on redhat linux version 2.6.18-53.el5. We also use the NFStoolkit to export the filesystems to different clients. From the server end the filesystems seem to be exported, however when I try to mount it on the client, I'm unable to mount the filesystems and the mount command fails with the error message 'Permission denied'. On the server side ' mount request from unknown host 10.0.0.10 for /local/a (/local/a)' messages are seen in the /var/log/messages file. The exporting of the filesystems is done by the serviceguard package and the filesystems are exported to the net group. I have copied information from netgroup file and the showmount -e command here.

Thanks in advance for all your help

Regards
Kaushik

[root@esuk1ds1 log]# showmount -e
Export list for esuk1ds1:
/local/a @esuk1ds-farm
/local/opt @esuk1ds-farm
/local/home @esuk1ds-farm


esuk1ds-farm (esuk1ds1-p,,uk.eu.airbus.corp),(esuk1ds2-p,,uk.eu.airbus.corp),(nfslocal,,uk.eu.airbus.corp),(esuk1
man,,uk.eu.airbus.corp),(esuk1010,,uk.eu.airbus.corp),(esuk1011,,uk.eu.airbus.corp),(esuk1012,,uk.eu.airbus.corp),(es
uk1013,,uk.eu.airbus.corp),(esuk1014,,uk.eu.airbus.corp),(esuk1015,,uk.eu.airbus.corp),(esuk1016,,uk.eu.airbus.corp),
(esuk1017,,uk.eu.airbus.corp),(esuk1018,,uk.eu.airbus.corp),(esuk1019,,uk.eu.airbus.corp),(esuk1020,,uk.eu.airbus.cor
p),(esuk1021,,uk.eu.airbus.corp),(esuk1022,,uk.eu.airbus.corp),(esuk1023,,uk.eu.airbus.corp),(esuk1024,,uk.eu.airbus.
corp),(esuk1025,,uk.eu.airbus.corp),(esuk1026,,uk.eu.airbus.corp),(esuk1027,,uk.eu.airbus.corp),(esuk1028,,uk.eu.airb
us.corp),(esuk1029,,uk.eu.airbus.corp),(esuk1030,,uk.eu.airbus.corp),(esuk1031,,uk.eu.airbus.corp),(esuk1032,,uk.eu.a
irbus.corp),(esuk1033,,uk.eu.airbus.corp),(esuk1034,,uk.eu.airbus.corp),(esuk1035,,uk.eu.airbus.corp),(esuk1036,,uk.e
u.airbus.corp),(esuk1037,,uk.eu.airbus.corp),(esuk1038,,uk.eu.airbus.corp),(esuk1039,,uk.eu.airbus.corp),(esuk1040,,u
k.eu.airbus.corp),(esuk1041,,uk.eu.airbus.corp),(esuk1042,,uk.eu.airbus.corp),(esuk1043,,uk.eu.airbus.corp),(esuk1044
,,uk.eu.airbus.corp),(esuk1045,,uk.eu.airbus.corp),(esuk1046,,uk.eu.airbus.corp),(esuk1047,,uk.eu.airbus.corp),(esuk1
048,,uk.eu.airbus.corp),(esuk1049,,uk.eu.airbus.corp),(esuk1050,,uk.eu.airbus.corp),(esuk1051,,uk.eu.airbus.corp),(es
uk1052,,uk.eu.airbus.corp),(esuk1053,,uk.eu.airbus.corp),(esuk1054,,uk.eu.airbus.corp),(esuk1055,,uk.eu.airbus.corp),
(esuk1056,,uk.eu.airbus.corp),(esuk1057,,uk.eu.airbus.corp),(,,)

[Steven Schweda]

I know nothing, but "mount request from
unknown host 10.0.0.10" suggests that the
server can't translate that IP address to a
name, which sounds like a problem with DNS
(or /etc/hosts, or NIS, or whatever,
depending on how you expect to do
name-address resolution).

[kaushikbr]

Hi Steven

I agree with you, when I export the filesystems explicitly to the full IPv4 IP address of the client, I can mount the filesystems on the client. The server is unable to resolv the hostname even when the filesystems is exported to a wildcarded IP address meaning exported to 10.0.0.*.

I've searched different forums and on google.
In all these forums it was recomended to use host, dig instead of nslookup, and to update the resolv.conf and nsswitch.conf.

The resolv.conf and nsswitch.conf on my machine looks like ---

/etc/resolv.conf
search localdomain
nameserver 127.0.0.1

/etc/nsswitch.conf
passwd: files
shadow: files
group: files
hosts: files
bootparams: nisplus [NOTFOUND=return] files
ethers: files
netmasks: files
networks: files
protocols: files
rpc: files
services: files
netgroup: files nisplus
publickey: nisplus
automount: files nisplus
aliases: files nisplus

I have all the IP addresses in the /etc/hosts file.

Since we use a private network, we do not have a DNS server.

Thanks in advance for all your replies.

Regards
Kaushik

[kaushikbr]

hi

In the process of investigation I've found something useful.

By exporting the filesystems to the entire subnet using

/local/a 10.0.0.0/255.255.255.0(rw,sync) -
I'm able to mount the filesystems on all the hosts.

However I'm still not able to fix the problem of the host resolution.

The host command still comes back with ';; connection timed out; no servers could be reached' and I'm not able to force the host lookup to use the /etc/hosts file.


Thanks in advance for all your suggestions.

Regards
Kaushik

[Matti_Kurkela]

The message ';; connection timed out; no servers could be reached' seems to indicate that the system is failing in trying to access a DNS server (maybe on 127.0.0.1, as your resolv.conf indicates).

Remember that processes generally read configuration files like /etc/nsswitch.conf only when they're starting up. If you've made changes to your nsswitch.conf file while your NFS daemons have already been running, the daemons might still be using the old settings.

MK