[Bug 2088282] Re: kernel-nfs-server does not work at all

Status changed to 'Confirmed' because the bug affects multiple users.

** Changed in: linux (Ubuntu)
Status: New => Confirmed

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https://bugs.launchpad.net/bugs/2088282

Title:
kernel-nfs-server does not work at all

Status in linux package in Ubuntu:
Confirmed

Bug description:
I'm trying to setup a NFSv4 server on Ubuntu LTS 24.04 but it does not
work at all. The client (no matter whether Ubuntu 22.04.4 LTS, or
Solaris 11.3.x, or ...) sends a V4 Null call, the server receives the
paket on the related interface and ACKs it, but in never sends an
answer.

The server setup has been made the same way we did with our focal
server (applied the /etc/default/*nfs* to /etc/nfs.conf). Same clients
used to test the noble nfs server work fine with the focal nfs server.
This and the paket captures suggests that this must be nfsd/kernel
problem.

The setup is basically:
1) zfs create -o mountpoint=/export -p pool1/${HOST}/export
2) zfs create pool1/${HOST}/export/iks/backup
3) zfs set sharenfs=sec=sys,secure,sync,crossmnt,no_subtree_check,root_squash,rw=@141.44.21.94/31 pool1/${HOST}/export/iks/backup
4) adjust /etc/nfs.conf if needed (basically sed -ire '/^#*vers3=/ s/^.*/vers3=n/' -e 's/^#*vers(4[^=]*)=.*/vers\1=y/' -e '/^\[nfsd\]/ a\debug=all' /etc/nfs.conf )
5) optionally restart nfs-server: systemctl restart nfs-server

The only difference wrt. to the focal instance setup is, that on focal there is no statd and no mountd running (NFSv4 does not need them AFAIK), but haven't found a way on noble, how to disable them (and systemd nfs-server is not smart enough to disable them). The /etc/default/nfs-common looks like this:
```
STATDOPTS=
NEED_GSSD=no
NEED_STATD=no
NEED_IDMAPD=yes
```
and /etc/default/nfs-kernel-server
```
RPCNFSDCOUNT=32
RPCNFSDPRIORITY=0
RPCMOUNTDOPTS="--manage-gids --no-nfs-version 2 --no-nfs-version 3"
NEED_SVCGSSD=""
RPCSVCGSSDOPTS=""
```

Not sure how to map the NEED_* to /etc/nfs.conf, but beside this and
thread count it should be the same as the attached /etc/nfs.conf.


So it should work but does not at all, even if I set sharenfs=off and use /etc/exports with `/export/iks/backup 141.44.21.94/31(sync,wdelay,hide,crossmnt,no_subtree_check,mountpoint,sec=sys,rw,secure,root_squash,no_all_squash)`.

exportfs always shows:
```
/export/iks/backup
141.44.21.94/31
```
and thus should work.

Last but not least I found and tried
https://ppa.launchpadcontent.net/mehmetbasaran/linux-6.8.0-45.45-nfs-
patch/ubuntu but unfortunately it behaves like the linux-
image-6.8.0-48-generic - no answer to V4 NULL calls.

So are there any kernels in Ubuntu 24.04 (noble), where the nfsd actually works?
And optionally: Is there a way to permanently turn off statd and mountd daemons?

--
version.log: Ubuntu 6.8.0-46.2-generic-nfs 6.8.12
About Ubuntu: Ubuntu 22.04.4 LTS

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