NFS in a Centos 6 LXC Proxmox 4.1

Posted on January 28, 2016  •  2 minutes  • 365 words  •  Suggest Changes

Getting NFS to work seems a bit of a grey area for LXC … I only recently switched part of our infrastructure over to LXC. But no NFS would be definitely a no-go.

We only work in a virtualized environment because its easy for backups and to efficiently use the computational resources on each of our server. That’s the reason, security of what a container can do, is only a second to functionality. On top of that, most of these containers are not giving out a service to the outside world, the only reason they have a connection to the web is for LAN and updates. So before you use this “guide”, know that I did not look into it.

Installing NFS

I started by updating & installing nfs common’s.

# updates
yum update -y

# install nfs
yum install nfs-utils nfs-utils-lib

Next I tried to start & keep them online after reboot.

# mark them as start-during-boot
chkconfig rpcbind on
chkconfig nfs on 

# start the services
service rpcbind start
service nfs start

I received this error :

Starting NFS daemon: rpc.nfsd: Unable to access /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 problem

Which I believe means, that some of the nfs kernel modules was not loaded when the container was started. This was solved by installing nfs-kernel-server on the proxmox head.

apt-get install nfs-kernel-server

I also needed to add an exception to apparmor, I don’t know exactly how apparmor works, but it can be overruled in the lxc configuration (/etc/pve/lxc/101.conf) with : (add)

lxc.aa_profile: unconfined

After that I restarted the container in proxmox webgui. (cause I don’t know the console commands 🙂 ) I retried and the services started. Although I found that NFS was not reporting as working :

service nfs status
rpc.svcgssd is stopped
rpc.mountd (pid 1061) is running...
nfsd dead but subsys locked

However a mount from an external machine worked.

/etc/exports from lxc container

/data *(rw,sync,no_root_squash,no_subtree_check)

and a soft mount from the client (non lxc in this test)

mount -o soft,rw lxc_ip:/data /mnt/tmp

So not 100% its save, but its working 🙂