[Users] rpc.idmapd in container

[Björn Lindgren]

On 04/26/2012 05:53 PM, Kir Kolyshkin wrote:
> On 04/23/2012 12:34 PM, Björn Lindgren wrote:
>> Hi,
>>
>> I'm trying to setup NFS4 in a container but are having trouble 
>> getting the rpc.idmapd daemon process to work.
>>
>> At startup rpc.idmapd tries to access two proc files which are 
>> missing in the container.
>>
>> /proc/net/rpc/nfs4.nametoid/channel
>> /proc/net/rpc/nfs4.idtoname/channel
>>
>> They are available on the host node through kernel module nfsd.ko
>>
>> How do I configure OpenVZ to get these?
>>
>> Running CentOS 6.2 with 
>> 042stab053.5<http://wiki.openvz.org/News/updates#Kernel_RHEL6_042stab053.5_released>
>
> NFS server (and client) inside container is fully supported, for it to 
> work you need to
> (1) have kernel module nfsd loaded before starting CT
> (2) have feature nfsd turned on for CT
>
> Both of this is described at 
> http://wiki.openvz.org/NFS_server_inside_container
>
> Having said that, only NFS v2 and NFS v3 are supported inside CT.
>
> We are currently working on making NFS v4 work inside containers, but 
> we do it for mainline
> kernels rather than in RHEL6 kernel. So whenever we will port OpenVZ 
> to any of 3.3 kernels,
> it will most probably have NFS v4 support. RHEL7-based OpenVZ kernel 
> will have it, too.
>
> Is there any specific reason why you need NFS v4 and not v3?

Thanks for clarifying the status of NFSv4 support in OpenVZ.

We are currently using NFSv3 and some of our applications are dependent 
on the file locking feature (fcntl/fcntl64 syscall) and we have had 
troubles getting remote locking to work correctly between CT and the NFS 
server. Sometimes it do work, but suddenly it stop working or stop 
working after a reboot of the CT. Looks like it is related to the 
out-of-band communication between the CT and rpc.lockd on the NFS 
server, or in the locking functionality in the kernel space in VE or NFS 
server.

We have found an work-around to the issue by resort to enforcing local 
locking with mount option "nolock", this enables the applications to run 
on top of NFSv3 in the VE.

Regards,
Bjorn

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://openvz.org/pipermail/users/attachments/20120430/e70d9acc/attachment.html