nixos nfs
I migrated from FreeBSD to NixOS for my nas. Apparently I never tested/used NFS on the new OS. When I went to mount my music share from my OpenBSD client I received the following error.
NFS Portmap: RPC: Program not registered
I followed this guide to add NFS to the NixOS config.
That partially worked. I could use the local client in the example to connect and an Arch Linux client could connect. But my OpenBSD client would not connect.
After some (ok a lot) of searching I stumbled upon this guide, which suggested to run the below rpcinfo commands.
rpcinfo -t hostname mountd
rpcinfo -u hostname mountd
rpcinfo -t hostname nfs
rpcinfo -u hostname nfs
When I got to this one it became obvious what was really going on.
rpcinfo -u nas nfs
rpcinfo: RPC: Program not registered
program 100003 is not available
It turns out that OpenBSD defaults to using UDP for NFS and Linux defaults to TCP. When I had ran my rpcinfo command I didn’t notice that there was a UDP entry missing for the NFS service.
rpcinfo -p nas
program vers proto port
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 4000 status
100024 1 tcp 4000 status
100005 1 udp 4002 mountd
100005 1 tcp 4002 mountd
100005 2 udp 4002 mountd
100005 2 tcp 4002 mountd
100005 3 udp 4002 mountd
100005 3 tcp 4002 mountd
100003 3 tcp 2049 nfs
100003 4 tcp 2049 nfs
100227 3 tcp 2049
100021 1 udp 4001 nlockmgr
100021 3 udp 4001 nlockmgr
100021 4 udp 4001 nlockmgr
100021 1 tcp 4001 nlockmgr
100021 3 tcp 4001 nlockmgr
100021 4 tcp 4001 nlockmgr
showmount -e nas
Exports list on nas:
export 192.168.88.0/24
export/music 192.168.88.0/24
I tried mount_nfs with the -T option to specify using TCP and it worked!
mount_nfs -T nas:/export/music /mnt/nas-media
I then hunted around for the flag for NixOS to add a UDP service for NFS. You need to add udp=y. The below is the NFS config for my NixOS.
services = {
nfs = {
server.enable = true;
server.exports = ''
/export 192.168.88.0/24(rw,fsid=0,no_subtree_check)
/export/music 192.168.88.0/24(rw,nohide,insecure,no_subtree_check)
'';
# for nvsv3
# fixed rpc.statd port; for firewall
server.statdPort = 4000;
server.lockdPort = 4001;
server.mountdPort = 4002;
server.extraNfsdConfig = ''udp=y'';
}:
}:
After upgrading to nixos 24.05 services.nfs.server.extraNfsConfig was deprecated. You now use services.nfs.settings. That config would like the below.
services = {
nfs = {
server.enable = true;
server.exports = ''
/export 192.168.88.0/24(rw,fsid=0,no_subtree_check)
/export/music 192.168.88.0/24(rw,nohide,insecure,no_subtree_check)
'';
# for nvsv3
# fixed rpc.statd port; for firewall
server.statdPort = 4000;
server.lockdPort = 4001;
server.mountdPort = 4002;
settings = {
nfsd.udp = true;
};
}:
}:
# Open ports in the firewall.
networking.firewall.enable = true;
networking.firewall.allowedTCPPorts = [ 111 2049 4000 4001 4002 20048 ];
networking.firewall.allowedUDPPorts = [ 111 2049 4000 4001 4002 20048 ];
Now rpcinfo shows:
rpcinfo -p nas
program vers proto port
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
100005 1 udp 4002 mountd
100005 1 tcp 4002 mountd
100005 2 udp 4002 mountd
100005 2 tcp 4002 mountd
100005 3 udp 4002 mountd
100005 3 tcp 4002 mountd
100024 1 udp 4000 status
100024 1 tcp 4000 status
100003 3 tcp 2049 nfs
100003 4 tcp 2049 nfs
100227 3 tcp 2049
100003 3 udp 2049 nfs
100227 3 udp 2049
100021 1 udp 4001 nlockmgr
100021 3 udp 4001 nlockmgr
100021 4 udp 4001 nlockmgr
100021 1 tcp 4001 nlockmgr
100021 3 tcp 4001 nlockmgr
100021 4 tcp 4001 nlockmgr
Also NixOS supports NFS versions 3 through 4.2 and OpenBSD supports versions 2 and 3. However both OSs do successfully negotiate to use version 3.