[Bug 1590799] Re: nfs-kernel-server does not start because of dependency failure

linuxball 1590799 at bugs.launchpad.net
Wed Nov 30 16:58:03 UTC 2016 

I confirm that this bug also affects my Ubuntu 16.04.1 LTS (GNU/Linux
4.4.0-51-lowlatency i686) system (with all updates as of today, even
those from xenial-proposed).

However, in my case the failure (rpc.mountd[<number>]: mountd: could not
create listeners) occured only in about 50% of all boot processes and
the system booted without this failure elsewise.

Using journalctl I could narrow the error down: It is a race condition:
The error occurs when rpcbind is not yet ready when rpc.mountd is
started and it does not occur when rpcbind is already ready at the time
rpc.mountd starts.

So Malcolm Scott gives the correct solution (add dependency and order
information to systemd) in comment #6. I created the snippet
/etc/systemd/system/nfs-mountd.service.d/rpcbind-dep.conf:

[Unit]
Wants=rpcbind.service
After=rpcbind.service

and updated the initramfs (update-initramfs -u) and now the bug has
gone. For a clean bug fix the above two lines should be added to
/lib/systemd/system/nfs-mountd.service by the maintainers of the nfs-
kernel-server package.

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Title:
  nfs-kernel-server does not start because of dependency failure

Status in nfs-utils package in Ubuntu:
  Confirmed

Bug description:
  Immediately after boot:

  root at feynmann:~# systemctl status nfs-kernel-server
  ● nfs-server.service - NFS server and services
     Loaded: loaded (/lib/systemd/system/nfs-server.service; enabled; vendor preset: enabled)
     Active: inactive (dead)

  Jun 09 14:35:47 feynmann systemd[1]: Dependency failed for NFS server and services.
  Jun 09 14:35:47 feynmann systemd[1]: nfs-server.service: Job nfs-server.service/start failed
   
  root at feynmann:~# systemctl status nfs-mountd.service 
  ● nfs-mountd.service - NFS Mount Daemon
     Loaded: loaded (/lib/systemd/system/nfs-mountd.service; static; vendor preset: enabled)
     Active: failed (Result: exit-code) since Thu 2016-06-09 14:35:47 BST; 7min ago
    Process: 1321 ExecStart=/usr/sbin/rpc.mountd $RPCMOUNTDARGS (code=exited, status=1/FAILURE)

  Jun 09 14:35:47 feynmann systemd[1]: Starting NFS Mount Daemon...
  Jun 09 14:35:47 feynmann rpc.mountd[1321]: mountd: could not create listeners
  Jun 09 14:35:47 feynmann systemd[1]: nfs-mountd.service: Control process exited, code=exited 
  Jun 09 14:35:47 feynmann systemd[1]: Failed to start NFS Mount Daemon.
  Jun 09 14:35:47 feynmann systemd[1]: nfs-mountd.service: Unit entered failed state.
  Jun 09 14:35:47 feynmann systemd[1]: nfs-mountd.service: Failed with result 'exit-code'.

  root at feynmann:~# systemctl list-dependencies nfs-kernel-server
  nfs-kernel-server.service
  ● ├─auth-rpcgss-module.service
  ● ├─nfs-config.service
  ● ├─nfs-idmapd.service
  ● ├─nfs-mountd.service
  ● ├─proc-fs-nfsd.mount
  ● ├─rpc-svcgssd.service
  ● ├─system.slice
  ● ├─network.target
  ● └─rpcbind.target
  ●   └─rpcbind.service

  root at feynmann:~# systemctl list-dependencies nfs-mountd.service 
  nfs-mountd.service
  ● ├─nfs-config.service
  ● ├─nfs-server.service
  ● ├─proc-fs-nfsd.mount
  ● └─system.slice
  root at feynmann:~# 

  root at feynmann:~# lsb_release -rd
  Description:	Ubuntu 16.04 LTS
  Release:	16.04

  root at feynmann:~# apt-cache policy nfs-kernel-server
  nfs-kernel-server:
    Installed: 1:1.2.8-9ubuntu12
    Candidate: 1:1.2.8-9ubuntu12
    Version table:
   *** 1:1.2.8-9ubuntu12 500
          500 http://gb.archive.ubuntu.com/ubuntu xenial/main amd64 Packages
          100 /var/lib/dpkg/status

  Additional comments:

      1. There seems to be a circular dependency between nfs-mountd and nfs-kernel-server
      2. I can get it working by changing the AFter,Requires in /lib/ssystemd/system/nfs-{mountd|server}.service files. I have managed to get nfs-kernel-server to start but not nfs-mountd.
      3. /usr/lib/systemd/scripts/nfs-utils_env.sh references /etc/sysconfig/nfs which is Centos/RedHat location of this file. Also /etc/default/nfs does not exist. (possibly unrelated to this bug)
      4. A file "/lib/systemd/system/-.slice" exists. this file prevents execution of 'ls *' or 'grep xxx *' commands in that directory. I am unsure whether this is intended by the systemd developers but it is unfriendly when investigating this bug.

  Attempted solution:

      1. Edit /lib/systemd/system/nfs-server.service (original lines are
  commented out:

  [Unit]
  Description=NFS server and services
  DefaultDependencies=no
  Requires=network.target proc-fs-nfsd.mount rpcbind.target
  # Requires=nfs-mountd.service
  Wants=nfs-idmapd.service
         
  After=local-fs.target
  #After=network.target proc-fs-nfsd.mount rpcbind.target nfs-mountd.service
  After=network.target proc-fs-nfsd.mount rpcbind.target 
  After=nfs-idmapd.service rpc-statd.service
  #Before=rpc-statd-notify.service
  Before=nfs-mountd.service rpc-statd-notify.service
  ...

  followed by a systemctl daemon-reload and a reboot.

  This results in nfs-kernel-server starting correctly but nfs-mountd
  not so. However starting nfs-mountd manually after reboot is
  successful:

  root at feynmann:~# systemctl status nfs-kernel-server.service 
  ● nfs-server.service - NFS server and services
     Loaded: loaded (/lib/systemd/system/nfs-server.service; enabled; vendor preset: enabled)
     Active: active (exited) since Thu 2016-06-09 15:07:23 BST; 1min 25s ago
    Process: 1391 ExecStart=/usr/sbin/rpc.nfsd $RPCNFSDARGS (code=exited, status=0/SUCCESS)
    Process: 1384 ExecStartPre=/usr/sbin/exportfs -r (code=exited, status=0/SUCCESS)
   Main PID: 1391 (code=exited, status=0/SUCCESS)
      Tasks: 0
     Memory: 0B
        CPU: 0
     CGroup: /system.slice/nfs-server.service

  Jun 09 15:07:23 feynmann systemd[1]: Starting NFS server and services...
  Jun 09 15:07:23 feynmann systemd[1]: Started NFS server and services.

  root at feynmann:~# systemctl status nfs-mountd.service 
  ● nfs-mountd.service - NFS Mount Daemon
     Loaded: loaded (/lib/systemd/system/nfs-mountd.service; static; vendor preset: enabled)
     Active: inactive (dead)

  root at feynmann:~# systemctl start nfs-mountd.service
   
  root at feynmann:~# systemctl status nfs-mountd.service 
  ● nfs-mountd.service - NFS Mount Daemon
     Loaded: loaded (/lib/systemd/system/nfs-mountd.service; static; vendor preset: enabled)
     Active: active (running) since Thu 2016-06-09 15:09:02 BST; 3s ago
    Process: 2044 ExecStart=/usr/sbin/rpc.mountd $RPCMOUNTDARGS (code=exited, status=0/SUCCESS)
   Main PID: 2046 (rpc.mountd)
      Tasks: 1
     Memory: 904.0K
        CPU: 12ms
     CGroup: /system.slice/nfs-mountd.service
             └─2046 /usr/sbin/rpc.mountd --manage-gids

  Jun 09 15:09:02 feynmann systemd[1]: Starting NFS Mount Daemon...
  Jun 09 15:09:02 feynmann rpc.mountd[2046]: Version 1.2.8 starting
  Jun 09 15:09:02 feynmann systemd[1]: Started NFS Mount Daemon.

  Enabling nfs-mountd.service (systemctl enable nfs-mountd.service) has
  no effect in this case.

  ProblemType: Bug
  DistroRelease: Ubuntu 16.04
  Package: nfs-kernel-server 1:1.2.8-9ubuntu12 [modified: lib/systemd/system/nfs-server.service]
  ProcVersionSignature: Ubuntu 4.4.0-22.40-generic 4.4.8
  Uname: Linux 4.4.0-22-generic x86_64
  ApportVersion: 2.20.1-0ubuntu2.1
  Architecture: amd64
  Date: Thu Jun  9 14:38:58 2016
  InstallationDate: Installed on 2016-06-08 (1 days ago)
  InstallationMedia: Ubuntu-Server 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.3)
  ProcEnviron:
   SHELL=/bin/bash
   TERM=linux
   PATH=(custom, no user)
   LANG=en_GB.UTF-8
   LANGUAGE=en_GB:en
  SourcePackage: nfs-utils
  UpgradeStatus: No upgrade log present (probably fresh install)

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