NFS

2009-03-19T11:39:10Z

Adrimcgrady: /* ISSUE: can't install nfs-common on ubuntu VE */

This page describes how to mount NFS partition inside a container.

== NFS server ==
Currently OpenVZ kernel doesn't include kernel NFS server support. However you are still able to use user space [[NFS server inside container]].

== NFS client ==
=== Preparations ===
==== Prerequisites ====
You will need the following software:

# vzctl version 3.0.13 or higher (do <code>vzctl --version</code>)
# kernel version 2.6.18-028test006 or higher (2.6.18-028stab* will do), or any recent RHEL5-based or 2.6.20-based kernel.

Note: In all the kernels earlier than 028stab038, kernel NFS support can be given to a container by setting:

sunrpc.ve_allow_rpc = 1
fs.nfs.ve_allow_nfs = 1
kernel.ve_allow_kthreads = 1

This can be done by adding the above lines into /etc/sysctl.conf on the hardware node, and then running <code>sysctl -p</code>.

===== Debian Notes =====

Debian Etch still uses vzctl version 3.0.11 and so NFS client support is not yet available. Lenny presently has version 3.0.18.

==== Prepare the HN ====

For NFS mounts to work in the containers with the RHEL5-based kernels you must enable kernel threads in the container by setting <code>kernel.ve_allow_kthreads=1</code> in <code>/etc/sysctl.conf</code>.

# modprobe nfs

You will probably want the nfs module to load automatically on reboots. One way to do this is to put the modprobe command in your /etc/rc.d/rc.local file:

modprobe nfs

==== Prepare the container ====
To allow a container to use NFS filesystem, you will need to start it with "nfs" feature enabled. If the container is running while you set the <code>--features nfs:on</code>, you will need to reboot it.

# vzctl set 101 --features "nfs:on" --save
# vzctl start 101

After this you may see nfs in <code>/proc/filesystems</code>
<pre>
# vzctl exec 101 cat /proc/filesystems
ext3
ext2
nodev rpc_pipefs
nodev proc
nodev nfs
nodev sysfs
nodev tmpfs
nodev devpts
</pre>

=== Mounting NFS ===
Make sure that packages <code>nfs-utils</code> and <code>nfs-utils-lib</code> or similar are installed in a container.

Assuming that you already have NFS server set up at <code>192.168.0.1:/nfs_pub</code>, mounting will be simple
<pre>
# vzctl enter 100
# mkdir /nfs
# mount -t nfs 192.168.0.1:/nfs_pub /nfs
# cat /proc/mounts
simfs / simfs rw 0 0
proc /proc proc rw 0 0
sysfs /sys sysfs rw 0 0
devpts /dev/pts devpts rw 0 0
nfs /nfs nfs rw,vers=3,rsize=32768,wsize=32768,hard,proto=tcp,timeo=600,retrans=2,sec=sys,addr=192.168.0.1 0 0
</pre>

For more details on how to setup NFS mount, see [http://nfs.sourceforge.net/nfs-howto/ar01s04.html NFS-client HOWTO]

=== Known issues ===
* There are quite a few parameters in NFS, so sometimes it doesn't work due to misconfiguration. We've created a separate
page describing such situations: [[NFS doesn't work]].
* Suspend and migrate operations fail if the VE has NFS partitions mounted [http://bugzilla.openvz.org/show_bug.cgi?id=616]

== ISSUE: can't install nfs-common on ubuntu VE ==

Host machine is ubuntu server 8.0.4 , VE container is ubuntu from openvz template repo.

Despite following all of the above directives, I am unable to get nfs-common to install on the VE (installs fine on the host machine).

Here is output ''(from inside VE)'' when I try to install nfs-common

<pre>
root@clinton:/# apt-get install nfs-common
Reading package lists... Done
Building dependency tree
Reading state information... Done
nfs-common is already the newest version.
0 upgraded, 0 newly installed, 0 to remove and 4 not upgraded.
1 not fully installed or removed.
After this operation, 0B of additional disk space will be used.
Setting up nfs-common (1:1.1.2-2ubuntu2.2) ...
* Starting NFS common utilities [fail]
invoke-rc.d: initscript nfs-common, action "start" failed.
dpkg: error processing nfs-common (--configure):
subprocess post-installation script returned error exit status 1
Errors were encountered while processing:
nfs-common
E: Sub-process /usr/bin/dpkg returned an error code (1)
</pre>

The cause of this problem is that portmap is not running. Portmat must be running before installing nfs-common.

Just run portmap:

# /etc/init.d/portmap start

Then, install nfs-common:

# apt-get install nfs-common

== See also ==
* [http://nfs.sourceforge.net/nfs-howto/ar01s04.html NFS-client HOWTO]
[[Category: HOWTO]]

OpenVZ Virtuozzo Containers Wiki - User contributions [en]

NFS