xe sr-probe does not find NFSv4/NFSv4.1

[borzel]

Background:

• XCP-ng 7.6 (with all extras/testing packages up to date)
• FreeNAS-11.2-RELEASE-U1 as NFS-Server (NFSv4 enabled)

Steps:

1. enable NFSv4 on FreeNAS and reboot it to fully enable it (!)
   
2. Create new SR with XCP-ng Center (https://github.com/xcp-ng/xenadmin/releases/tag/v7.6.3.21) with NFSv4.1 (or XenOrchestra -> this step just proves NFSv4.1 support)
   
3. Detach SR
4. run xe sr-probe type=nfs device-config:server=<some-ip> device-config:serverpath=/mnt/testpool/nfsv41test device-config:probeversion

Output of sr-probe

<?xml version="1.0" ?>
<SRlist>
        <SR>
                <UUID>2131f8f8-49be-0868-2b97-d624c9851584</UUID>
        </SR>
        <SR>
                <UUID>cce30ede-0fd2-b34a-04e5-291b56b9f8fc</UUID>
        </SR>
        <SupportedVersions>
                <Version>3</Version>
        </SupportedVersions>
</SRlist>

Expected result
Shows SupportedVersions 3, 4 and 4.1

[thctlo]

Hm getting :
Host Xen XCP 7.6.3 , NFSv4 enabled Server Debian 9.
exports file contains.
/srv/nfs4 192.168.xxx.0/24(rw,sync,fsid=0,crossmnt,no_subtree_check,sec=sys:krb5:krb5i:krb5p)
/srv/nfs4/xcphosts 192.168.xxx.0/24(rw,sync,no_subtree_check,sec=sys:krb5:krb5i:krb5p)

This current setup works for v3/v4/v4.1 with and without kerberos mounts.

xe sr-probe type=nfs device-config:server=IP_HERE device-config:serverpath=/xen/nfs-stor device-config:probeversion
Error code: SR_BACKEND_FAILURE_73
Error parameters: , NFS mount error [opterr=mount failed with return code 32],

[thctlo]

running : xe sr-probe type=nfs device-config:server=IP_HERE device-config:probeversion

Error code: SR_BACKEND_FAILURE_101
Error parameters: , The request is missing the serverpath parameter, <?xml version="1.0" ?>
<nfs-exports>
<Export>
<Target>192.168.xxx.xxx</Target>
<Path>/srv/nfs4/xcphosts</Path>
<Accesslist>192.168.xxx.0/24</Accesslist>
</Export>
<Export>
<Target>192.168.xxx.xxx</Target>
<Path>/srv/nfs4</Path>
<Accesslist>192.168.xxx.0/24</Accesslist>
</Export>
</nfs-exports>

[stormi]

@borzel Is that a problem that occurs for any NFS share that supports NFS 4 or above, or only with specific servers?

[NormHenderson]

Not sure if it is related to the same root cause however: when xe sr-create specifies only type=nfs, it defaults to NFSv3 and will not negotiate NFSv4/NFSv4.1 share without adding device-config:nfsversion=4.1 (which isn't documented as far as I can tell). IMHO it should be starting with NFSv4.1 and negotiating downwards. (XCP-ng 8.1 connecting to nfs-kernel-server on Ubuntu 20.04)

[ondraknezour]

I had similar problem with FreeBSD NFS server set up with minimal NFS version 4 (vfs.nfsd.server_min_nfsvers=4 in the /etc/sysctl.conf file) [1].

I was told [2], that NFS v4 doesn't use RPC, so if support for older protocol version isn't needed, nfsd would not register with rcpbind, making function check_server_service in /opt/xensource/sm/nfs.py unreliable and invalid, because it checks for condition (nfs service in rpcinfo -s output) which is not always present.

[1] https://lists.freebsd.org/pipermail/freebsd-net/2021-January/057371.html
[2] https://lists.freebsd.org/pipermail/freebsd-net/2021-January/057372.html

[jcharaoui]

I've hit this bug with an NFSv4+ only server (eg. NFSv3 is disabled). XCP-ng is unable to add the SR because it depends on the presence of NFSv3 services.

[olivierlambert]

Then I think it should be reported upstream ASAP :)

https://github.com/xapi-project/sm/issues

[TristisOris]

still actual for Huawei storage.

[olivierlambert]

IIRC, this was fixed in a recent upstream SMAPI patch (but likely not yet available in XCP-ng. @stormi can you take a look where you are around? Thanks!

[stormi]

I don't remember commits that would address this, and the issue on the upstream repository got no answers from the devs.

Recent commits that are about NFS in sm are: xapi-project/sm@e121864 and xapi-project/sm@6fbff68 but I don't think they are related to this issue here.