Re: Questions and problems with NFS4

Chuck Lever
2010-07-28T18:08:38Z

On 07/27/10 06:46 PM, J.A. Magallón wrote:
> - AFAIK, with NFS4 the only needed daemons are nfsd and idmapd. And the
> only accesible port from the outside is 2049, for nfsd.
> I have tried to strip down my nfs server (-N 2 -N 3 -U),
> but rpcinfo still gives me:
>
> annwn:~# rpcinfo -p localhost
> program vers proto port service
> 100000 4 tcp 111 portmapper
> 100000 3 tcp 111 portmapper
> 100000 2 tcp 111 portmapper
> 100000 4 udp 111 portmapper
> 100000 3 udp 111 portmapper
> 100000 2 udp 111 portmapper
> 100024 1 udp 48461 status
> 100024 1 tcp 37515 status
> 100021 1 udp 38583 nlockmgr
> 100021 3 udp 38583 nlockmgr
> 100021 4 udp 38583 nlockmgr
> 100021 1 tcp 37873 nlockmgr
> 100021 3 tcp 37873 nlockmgr
> 100021 4 tcp 37873 nlockmgr
> 100003 4 tcp 2049 nfs
> 100005 1 udp 45341 mountd
> 100005 1 tcp 58639 mountd
>
> disabling portampper and mountd is just a matter of initscripts
> requirements, but how can I disable nlockmgr ? It isn't needed for
> NFS4, isn't it ? Nor portmapper nor mountd...

Strictly speaking, portmapper is not required for NFSv4 service.
However, the NFS infrastructure on Linux is still designed for NFSv2 and
v3. There remains some work needed to make portmapper optional for a
v4-only server. For now, continue to run it in order to handle kernel
upcalls.

rpc.mountd is, however, still required on Linux NFSv4 servers. Although
NFSv4 clients do not contact the server's mountd, the kernel's NFS
server performs upcalls to rpc.mountd to manage export information. You
can firewall off the mountd service on the server without affecting
NFSv4 clients. Recent versions of rpc.mountd accept command line
options that disable the mountd network service while still handling
kernel upcalls.

And, as long as lockd is running, you will need to keep rpc.statd
around. Again, you can firewall this service so that it is not exposed
on the network, but it must continue to be available to handle kernel
upcalls. This is something we hope to address eventually as part of the
lockd work Bruce mentioned.