If you have not already installed an NFS server, you should do so:

# yum install nfs-utils

Make a directory to contain the contents of the Oracle VM Server installation ISO that will be exported via NFS:

# mkdir -p /srv/install/ovs

Copy the entire contents of the Oracle VM Server installation ISO into this new directory:

# cp -r /mnt/* /srv/install/ovs

Substitute mnt with the path to the mount point where you mounted the ISO. Do not simply provide access to the ISO file itself via NFS; you need to make the contents available instead.

Now configure your NFS exports by editing the /etc/exports file to contain the following:

/srv/install *(ro,async,no_root_squash,no_subtree_check,insecure)

Depending on your security requirements, you may configure this export to only cater to particular hosts.

Start the NFS service:

# service nfs start

Configure the NFS service to always start at boot:

# chkconfig nfs on
# chkconfig nfslock on