~~NOTOC~~
====== NFS server ======

The NFS server can be used to provide a root file system that can be mounted root filesystem on the traget hardware, this is very convenient for application development. 


===== Tested with the following operating systems =====
  * Ubuntu 10.04 x86 in VMware Player
  * Ubuntu 12.04 x86 in VMware Player
  * Ubuntu 14.04 x86_64 in VMware Player
  * Ubuntu 16.04 x86_64 in VMware Player
===== Installation =====

On Ubuntu the nfs-kernel-server package has to be installed. 

<code bash>
user@ubuntu:~$ sudo apt-get install nfs-kernel-server
</code>
\\
----
===== Example Configuration for NFS boot =====
\\
Create a directory on the host root filesystem.
<code bash>
user@ubuntu:~$ sudo mkdir /nfs
user@ubuntu:~$ sudo chmod 777 /nfs
</code>

Extract the content of root.tgz to your nfs directory.\\
root.tgz is located in:
  * BSP download archive provided by TQ-Systems e.g. (TQMxx.BSP.SW.BIN.xxxx.tgz\TQMxx.BSP.SW.BIN.xxxx.tar\root.tgz)
  * After building the BSP sources with PTXdist e.g. (../TQMxx-BSP-REV.xxxx/platform-MBxx/images/root.tgz)
<code bash>
user@ubuntu:~$ cd /nfs
user@ubuntu:~$ sudo tar -xvf ~/workspace/TQMaxx-BSP-REV.xxxx/platform-MBaxx/images/root.tgz
</code>

Next step is to configure the ''/etc/exports'' file.
Create an entry that contains the path to your nfs folder created above.

<code>
<path/to/your/nfs/directory>       <permitted IPs>/<subnet>(<comma separated options>)
</code>

++++For example|
<code>
/nfs             192.168.0.0/255.255.0.0(rw,no_root_squash,async,no_subtree_check)
</code>
++++
<WRAP round important>
This path must match the U-Boot environment variable ''rootpath'' on the target and defines the source for the NFS rootfs.
</WRAP>

<WRAP round info>
After the /etc/exports file was modified the NFS server need to be restarted:
<code bash>
user@ubuntu:~$ sudo service nfs-kernel-server restart
</code>
</WRAP>
----
===== Test the configuration =====
\\
With the command ''showmount'' you can see the exported directories.
<code bash>
user@ubuntu:~$ showmount -e localhost
Export list for localhost:
/nfs 192.168.0.0/255.255.0.0
</code>

=====Related Links=====
\\
  * [[en:tftp|How to setup a TFTP Server on your Host Computer]]
  * [[en:general_information:tutorial:nfs_boot|Using NFS boot]]
===== Troubleshooting =====
\\
If the root file system cannot be mounted via NFS the log file of the NFS server should be checked. In Ubuntu the log is written to the file ''/var/log/syslog''.

An example of such a log entry looks like:

<code>
Nov 14 02:30:57 ubuntu mountd[8667]: refused mount request from 172.21.10.157 for /opt/ltib_iMX35/ltib/rootfs (/opt/ltib_iMX35/ltib/rootfs): unmatched host
</code>

In this case the server rejects the connection because the host does not match the one in the file ''/etc/exports''.


===== Sources =====
\\
  * https://help.ubuntu.com/community/SettingUpNFSHowTo
  * [[http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.8.|http://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.8.]]
  * http://www.centos.org/docs/5/html/Deployment_Guide-en-US/ch-nfs.html