Linux Ubuntu NFS – Mount.nfs: Access Denied by Server While Mounting on Ubuntu Machines

linuxmountnfsUbuntu

I have three machines in production – 

machineA    10.66.136.129
machineB    10.66.138.181
machineC    10.66.138.183

and all those machines have Ubuntu 12.04 installed in it and I have root access to all those three machines.

Now I am supposed to do below things in my above machines – 

Create mount point /opt/exhibitor/conf
Mount the directory in all servers.
 sudo mount <NFS-SERVER>:/opt/exhibitor/conf /opt/exhibitor/conf/

I have already created /opt/exhibitor/conf directory in all those three machines as mentioned above.

Now I am trying to create a Mount Point. So I followed the below process –

Install NFS support files and NFS kernel server in all the above three machines

$ sudo apt-get install nfs-common nfs-kernel-server

Create the shared directory in all the above three machines

$ mkdir /opt/exhibitor/conf/

Edited the /etc/exports and added the entry like this in all the above three machines – 

# /etc/exports: the access control list for filesystems which may be exported
#               to NFS clients.  See exports(5).
#
# Example for NFSv2 and NFSv3:
# /srv/homes       hostname1(rw,sync,no_subtree_check) hostname2(ro,sync,no_subtree_check)
#
# Example for NFSv4:
# /srv/nfs4        gss/krb5i(rw,sync,fsid=0,crossmnt,no_subtree_check)
# /srv/nfs4/homes  gss/krb5i(rw,sync,no_subtree_check)
#
/opt/exhibitor/conf/     10.66.136.129(rw)
/opt/exhibitor/conf/     10.66.138.181(rw)
/opt/exhibitor/conf/     10.66.138.183(rw)

I have tried mounting on machineA like below from machineB and machineC and it gives me this error- 

root@machineB:/# sudo mount -t nfs 10.66.136.129:/opt/exhibitor/conf /opt/exhibitor/conf/
mount.nfs: access denied by server while mounting 10.66.136.129:/opt/exhibitor/conf

root@machineC:/# sudo mount -t nfs 10.66.136.129:/opt/exhibitor/conf /opt/exhibitor/conf/
mount.nfs: access denied by server while mounting 10.66.136.129:/opt/exhibitor/conf

Did my /etc/exports file looks good? I am pretty sure, I have messed up my exports file. As I have the same content in all the three machines in exports file.

Any idea what wrong I am doing here? And what will be the correct /exports file here?

Best Answer

exportfs

When you create a /etc/exports file on a server you need to make sure that you export it. Typically you'll want to run this command:

$ exportfs -a

This will export all the entries in the exports file.

showmount

The other thing I'll often do is from other machines I'll check any machine that's exporting NFS shares to the network using the showmount command.

$ showmount -e <NFS server name>

Example

Say for example I'm logged into scully.

$ showmount -e mulder
Export list for mulder:
/export/raid1/isos     192.168.1.0/24
/export/raid1/proj     192.168.1.0/24
/export/raid1/data     192.168.1.0/24
/export/raid1/home     192.168.1.0/24
/export/raid1/packages 192.168.1.0/24

fstab

To mount these upon boots you'd add this line to your client machines that want to consume the NFS mounts.

server:/shared/dir /opt/mounted/dir nfs rsize=8192,wsize=8192,timeo=14,intr

automounting

If you're going to be rebooting these servers then I highly suggest you look into setting up automounting (autofs) instead of adding these entries to /etc/fstab. It's a bit more work but is well worth the effort.

Doing so will allow you to reboot the servers more independently from one another and also will only create the NFS mount when it's actually needed and/or being used. When it goes idle it will get unmounted.

References

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