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

Mon Feb 6 10:55:39 UTC 2017

Okay, sorry for the delay. It took me sometime to review all SysV,
Upstart scripts and Systemd unit files. What "linuxball" said is
correct, we're missing rpcbind dependency for nfs-mountd.service.

# nfs-server.service

[Unit]
...
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= nfs-idmapd.service rpc-statd.service
Before= rpc-statd-notify.service

Wants=auth-rpcgss-module.service
After=rpc-gssd.service rpc-svcgssd.service

Before=remote-fs-pre.target

Wants=nfs-config.service
After=nfs-config.service

As it stands, "rpcbind.target is being put as a dependency and to run
before "nfs-server.service" but not before "nfs-mountd.service":

[Unit]
...
Requires=proc-fs-nfsd.mount
After=proc-fs-nfsd.mount
After=network.target local-fs.target
BindsTo=nfs-server.service

Wants=nfs-config.service
After=nfs-config.service

Since the services run in parallel there is an window of opportunity for
"nfs-mountd.service" to be started before "rpcbind.target".

Only problem is that rpcbind.target is for synchronization with SysV
scripts:

rpcbind.target
The portmapper/rpcbind pulls in this target and orders itself before it, to indicate its availability. systemd automatically adds dependencies of type After= for this target unit to all SysV init script service units with an LSB header referring to the "$portmap" facility.

Right now we have:

system/nfs-server.service:Requires= ... rpcbind.target
system/nfs-server.service:After= ... rpcbind.target ...
system/rpc-statd.service:Requires= ... rpcbind.target
system/rpc-statd.service:After= ... rpcbind.target

So the correct fix would be:

Wants= ... rpcbind.target
After= ... rpcbind.target

For all NFS daemons depending on rpcbind to be fully operational, since
the systemd generators would take also care of SysV script dependencies
(allegedly if rpcbind is started through SysV generator).

The thing is that, this upstream discussion has taken place:

https://patchwork.kernel.org/patch/8976701/

I think I should move on and "cherry-pick" this change as well. Upstream
"Linux NFS" changed the dependency from "target" to "service" - which
makes perfectly sense based on the explanation from Neil Brown.

I'm providing a PPA soon and will ask for feedback and, at the same
time, I'll attach this small fix as a debdiff proposal for sponsors team
to upload it to -propose if your feedback is good. I'd like to ask you
to reproduce the issue and to make sure issue is gone with the package
I'll provide.

Sorry for the amount of time this bug was opened without a fix. I think it never gained much traction because the workaround as simple so people had stick with the workaround you guys provided. 
Jeroen, if you want to understand how Ubuntu development works, specifically for fixes you can read this Wiki: https://wiki.ubuntu.com/StableReleaseUpdates.

Will get back to this today.

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https://bugs.launchpad.net/bugs/1590799

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

Status in nfs-utils package in Ubuntu:
  In Progress
Status in nfs-utils source package in Xenial:
  New

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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