[Bug 1881847] Re: If NFS server reboots, client somethings fails to remount the file system properly

[Robert Dinse]

I'm sorry it was some time ago when I submitted this.  I have since
upgraded to 5.13.19 and 5.16 on some machines and these latter kernels seems
to have resolved the issue.

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On Mon, 14 Feb 2022, Andreas Hasenack wrote:

> Date: Mon, 14 Feb 2022 20:21:46 -0000
> From: Andreas Hasenack <1881847 at bugs.launchpad.net>
> To: nanook at eskimo.com
> Subject: [Bug 1881847] Re: If NFS server reboots,
>     client somethings fails to remount the file system properly
> 
> With NFSv4, user and group information is sent on the wire as names,
> instead of uids. And these names are qualified with a domain. So for
> example an exported directory containing files for the "ubuntu" user
> will have the ownership sent to NFSv4 clients as "ubuntu at DOMAIN", where
> "DOMAIN" is the DNS domain of the server.
>
> Whave I have seen in some testing is that after a reboot, for some
> reason (probably service ordering), the NFS server bits do not know yet
> the domain of the machine, and then this becomes "localdomain", and the
> user is sent to the client as "ubuntu at localdomain". The client, being on
> the same DNS domain, decides that "localdomain" is none of its business,
> and declares that user as "nobody".
>
> You said there was a "hang", but maybe the issue above is realted
> somehow? One way to see it is in the client logs, where "nfsidmap" is
> called. If you configure /etc/request-key.d/id_resolver.conf to call
> nfidmap with extra "-v -v -v" in the command line, it will be more
> verbose in /var/log/syslog and say which user it's trying to resolve.
>
> If you see the "localdomain" issue, then try hardcoding the domain in
> /etc/idmapd.conf on both the server and the client, to your actual DNS
> domain, and see if that helps.
>
>
> Hope this helps
>
> -- 
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1881847
>
> Title:
>  If NFS server reboots, client somethings fails to remount the file
>  system properly
>
> Status in nfs-utils package in Ubuntu:
>  New
>
> Bug description:
>  If the NFS server reboots, sometimes client servers fail to re-
>  establish the NFS mount properly.  This is using NFS v4.2.  The client
>  machine will hang if I try to do a df when an NFS mount is in this
>  condition.  Attempting to access a file will likewise hang
>  indefinitely.  This is a problem with the stock 5.3.0.x kernel and it
>  is a problem with 5.6 still.  I have not tried 5.7 yet.  I filed this
>  against nfs-kernel, but I am not 100% sure it is not nfs-common but
>  there is some sort of communications not happening between them.
>
>  ProblemType: Bug
>  DistroRelease: Ubuntu 20.04
>  Package: nfs-kernel-server 1:1.3.4-2.5ubuntu3
>  Uname: Linux 5.6.0 x86_64
>  ApportVersion: 2.20.11-0ubuntu27.2
>  Architecture: amd64
>  CasperMD5CheckResult: skip
>  CurrentDesktop: MATE
>  Date: Tue Jun  2 21:34:31 2020
>  InstallationDate: Installed on 2017-05-27 (1102 days ago)
>  InstallationMedia: Ubuntu-MATE 17.04 "Zesty Zapus" - Release amd64 (20170412)
>  SourcePackage: nfs-utils
>  UpgradeStatus: Upgraded to focal on 2020-04-26 (38 days ago)
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/ubuntu/+source/nfs-utils/+bug/1881847/+subscriptions
>

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https://bugs.launchpad.net/bugs/1881847

Title:
  If NFS server reboots, client somethings fails to remount the file
  system properly

Status in nfs-utils package in Ubuntu:
  New

Bug description:
  If the NFS server reboots, sometimes client servers fail to re-
  establish the NFS mount properly.  This is using NFS v4.2.  The client
  machine will hang if I try to do a df when an NFS mount is in this
  condition.  Attempting to access a file will likewise hang
  indefinitely.  This is a problem with the stock 5.3.0.x kernel and it
  is a problem with 5.6 still.  I have not tried 5.7 yet.  I filed this
  against nfs-kernel, but I am not 100% sure it is not nfs-common but
  there is some sort of communications not happening between them.

  ProblemType: Bug
  DistroRelease: Ubuntu 20.04
  Package: nfs-kernel-server 1:1.3.4-2.5ubuntu3
  Uname: Linux 5.6.0 x86_64
  ApportVersion: 2.20.11-0ubuntu27.2
  Architecture: amd64
  CasperMD5CheckResult: skip
  CurrentDesktop: MATE
  Date: Tue Jun  2 21:34:31 2020
  InstallationDate: Installed on 2017-05-27 (1102 days ago)
  InstallationMedia: Ubuntu-MATE 17.04 "Zesty Zapus" - Release amd64 (20170412)
  SourcePackage: nfs-utils
  UpgradeStatus: Upgraded to focal on 2020-04-26 (38 days ago)

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/nfs-utils/+bug/1881847/+subscriptions