How to force NFSv4.2 (server side)?

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1

Do we curently have a way of forcing using NFSv4?

Archwiki says that systemd has the option of running NFSv4 only, so I suppose that it is somewhere (not on the NixOS Wiki.

Do any of you know about this option?

2

Not sure if it is NFS4 only but I use:

fileSystems.“/mnt/nfs/share” = {
device = “server.domain:/file/store/stuff”;
fsType = “nfs4”;
};

Are you trying to prevent a fallback? I’ve not seen it happen, but could just be my setup…

I’d be interested in the answer too if I am misunderstanding!

1 Like
3

Just to be clear, I have a NFS server on NixOS and I want the files to be avalible only for nfs4 clients.

I have added the fsType to my bind mount:

fileSystems.${nfsDir} = { # see hardware-config.nix
    device = "/mnt/${discDir}";
    options = [ "bind" ];
    fsType = "nfs4";
  };

However, I do not think that this changes the nfs version avalibility:

user@notNix ~ $ rpcinfo -p 192.168.1.124 | grep nfs
    100003    3   tcp   2049  nfs
    100003    4   tcp   2049  nfs
    100227    3   tcp   2049  nfs_acl

Could you please provide the output of this command?

Are you trying to prevent a fallback?

Not really. I am trying to limit resource usage and improve security.
And of course play around with NixOS.

4

You can turn NFSv3 off on the server by using extraNfsdConfig:

services.nfs.server.extraNfsdConfig = ''
  UDP=off
  vers2=off
  vers3=off
'';

It writes the options for nfs.conf (see man pages for nfs.conf, rpc.nfsd)

1 Like
5

Thanks!
I have managed to set this config:

  services.nfs.server = { enable=true;
    exports = "${exportFileContents}";
    extraNfsdConfig =''
      rdma = true # Remote Direct Memory Access
      vers3 = false
      vers4 = true
      vers4.0 = false
      vers4.1 = false
      vers4.2 = true
    '';
  };
1 Like
6

This woked great. However extraNnfsdConfig got deprecated and now I cannot specify the “vers4.X” as nix recognizes it as a float.

Does anyone know how to do this?

7

Where is that deprecation?

8

I got a message when nixos-rebuilding saying that I should switch to the newer way.

9

Please post the entire error message verbatim without paraphrasing. I don’t see a deprecation warning in Nixpkgs on that option.

10

sorry, I was not at the PC at that moment. Here it is:

# nixos-rebuild test 
building Nix...
building the system configuration...
trace: warning: `services.nfs.server.extraNfsdConfig` is deprecated. Use `services.nfs.settings` instead.

these 19 derivations will be built:
[...]

Also if I try to use both I get

 error:
       Failed assertions:
       - `services.nfs.settings` cannot be used together with `services.nfs.extraConfig` and `services.nfs.server.extraNfsdConfig`.
11

No problem, the deprecation warning was in a place where I didn’t expect it. Having the error message makes it easier to locate.

Looks like you can just use something like:

services.nfs.settings = {
    nfsd = {
        rdma = true;
        vers2 = false;
        vers4 = true;
        [... and so on ...]
    };
};

In general, this will build the .ini file for NFS. The top-level attributes (in this case nfsd) will be turned into sections, and the key-value-pairs below will be turned into, well, key=value properly formatted for INI files.

12

And if you have a key that’d otherwise be nix syntax, you can quote it like this:

"vers4.2" = true;
2 Likes
13

This is what I was missing!
This is my config as of right now:

    settings = {
      nfsd.udp = false;
      nfsd.vers3 = false;
      nfsd.vers4 = true;
      nfsd."vers4.0" = false;
      nfsd."vers4.1" = false;
      nfsd."vers4.2" = true;
    };