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NFS server inside container

4,060 bytes added, 18:01, 4 August 2021
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There are two ways to setup NFS server on common [[HN]]:
use a user-space NFS server daemon or use an in-kernel implementation
of NFS server. Some peculiarities appear if you intend to run NFS serverin [[VE]].
{{Note|for information about NFS client inside VEcontainer, see [[NFS]].}}
== Kernel NFS server ==
Binary RPMs that are provided Kernel-space NFS server is supported by OpenVZ community contain latest RHEL5 and RHEL6 based kernels compiledand since vzctl-3.0.24. without NFS server NB! Currently only NFSv3 is supported - no NFSv4 supportyet. Thus you have  === Prerequisites ===In order torun an NFS server inside a container, make sure:[[Kernel build|recompile the * '''nfsd kernel]] with module is loaded on host system before starting a container'''* '''nfsd feature for a container is turned on''' (<code>vzctl set $CTID --feature nfsd:on --save</code>CONFIG_NFSD) ===mSetup ===* Make sure that rpcbind service is started before nfs service:: <code>chkconfig rpcbind on && service rpcbind start</code>. After booting * Disable NFSv4 and nfsd module loading warnings in this /etc/sysconfig/nfs by uncommenting the following lines: MOUNTD_NFS_V3="yes" RPCNFSDARGS="-N 4" NFSD_MODULE="noload"* Start NFS service:: <code>chkconfig nfs on && service nfs start</code> === Troubleshooting === Make sure that:# you have enabled nfsd feature for your container# nfsd kernel module is loaded before you started the container ==== rpcbind ==== If you'll be ablesee this:<pre># service nfs start...to use Starting NFS server on services: [[HN] OK ]Starting NFS quotas: Cannot register service: RPC: Unable to receive; errno = Connection refusedrpc.rquotad: unable to register (RQUOTAPROG, RQUOTAVERS, udp).</pre> It means you haven't started rpcbind service. Solution:<pre>chkconfig rpcbind on && service rpcbind start</pre> ==== nfsd module ====If you see this:<pre># service nfs start....In-kernel Starting NFS server runs kernel threads daemon: rpc.nfsd: Unable to service requests of clientsaccess /proc/fs/nfsd errno 2 (No such file or directory).Please try, as root, 'mount -t nfsd nfsd /proc/fs/nfsd' and then restart rpc.nfsd to correct the problemBut for security reasons kernel threads are prohibited in [[VEFAILED]]s! So # mount -t nfsd nfsd /proc/fs/nfsdmount: unknown filesystem type 'nfsd'</pre> It means you wonhaven'tloaded nfsd kernel module on host before starting container. ==== warnings ==== If you see this:<pre># /etc/init.d/nfs startFATAL: Module nfsd not found.FATAL: Error running install command for nfsdbe able ...</pre> It is actually harmless, you don't need to do anything. In case you want this to run NFS server inside [[VE]] without patching go away, uncomment (or add) the kernelline   NFSD_MODULE="noload" in <code>/etc/sysconfig/nfs</code> file.
== User-space NFS server ==
The reason is that these daemons check the major number of the device where the directory to export resides.
If major equals 0 then daemons assume that it is NFS and don't want to re-export it. Symptoms are
that clients will always get a "permission denied" error. Simfs (the file system on which VE container is located)
is associated with so called unnamed device, in which major equals 0. So, to prevent daemons from checking for
re-exporting — just use this <code>-r</code> option.
Please note that the user-space NFS server does not provide locking, or at least I couldn't get locking to work - [[User:Elronxenu|Elronxenu]] 19:49, 15 November 2007 (EST)
 
=== On Debian Lenny ===
 
The current stable debian version 5.0 (lenny) provides two packages for user space nfs support: <code>nfs-user-server</code> and <code>unfs3</code>. Here i describe my experiences with them --[[User:Strimo|Strimo]] 17:47, 16 February 2009 (UTC)
 
It seems that also the unfs3 package has been removed from the debian repositories. --[[Special:Contributions/95.21.175.189|95.21.175.189]] 23:39, 30 July 2011 (UTC)
 
==== nfs-user-server ====
 
IMPORTANT : read http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=515957 , nfs-user-server was removed
 
<pre>
aptitude install nfs-user-server
</pre>
 
First i used nfs-user-server package since i didn't know unfs3. After installing i always got the '''permission denied''' error when i tried to mount any exported path until i found this article. So i patched the /etc/init.d/nfs-user-server file to include the <code>-r</code> parameter by adding <code>-- -r</code> to the <code>start-stop-daemon</code> line responsible for starting <code>rpc.mountd</code> and <code>rpc.nfsd</code>:
 
<pre>
start-stop-daemon --start --oknodo --quiet --exec /usr/sbin/rpc.nfsd -- -r
start-stop-daemon --start --oknodo --quiet --exec /usr/sbin/rpc.mountd -- -r
</pre>
 
After the modification and a nfs server restart (<code>/etc/init.d/nfs-user-server restart</code>) i was able to mount a nfs share. At first the nfs server seems to work fine but anytime i want to edit any text file (using nano or mcedit) i got strange errors on writing to the file and i never solved the problem nor detected why this happens. So i switched to unfs3 ...
 
<b>Note</b>: nfsmount from busybox not works with nfs-user-server in Debian Lenny, it write message "rpc failed: 2" when I try boot from nfs server. unfs3 works fine.
Such problem into Ubuntu: https://bugs.launchpad.net/ubuntu/+source/nfs-user-server/+bug/189593
 
==== unfs3 ====
 
<pre>
aptitude install unfs3
</pre>
 
Works fine until now. Note that both unfs3 and nfs-user-server do not support file locking!
NOTE: I tested on centos 5.6 using unfs3 and I had to run the /etc/init.d/nfs service and see it work before I could use unfs. also use exports -a before using sudo /usr/sbin/unfsd -T -e /etc/exports
 
=== On CentOS 5 ===
 
If you are running RedHat/CentOS, you can [http://dag.wieers.com/rpm/packages/unfs3/ get unfs3 from the DAG repository]
== External links ==
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