[Bug 2063973] Re: network-online.target is reached before netplan-configured interfaces are online

[Lukas Märdian]

Waiting for all (non-optional) interfaces to be ready on a link-local
level ("degraded") and one interface having a global IP ("routable") is
now implemented in Netplan v1.1.

This is according to the "Definition of an online system" [spec]. And is
implemented via a /run/systemd/system/systemd-networkd-wait-
online.service.d/10-netplan.conf drop-in configuration generated by
Netplan.

[spec] https://discourse.ubuntu.com/t/spec-definition-of-an-online-
system/27838

** Changed in: netplan.io (Ubuntu)
       Status: Triaged => Fix Released

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https://bugs.launchpad.net/bugs/2063973

Title:
  network-online.target is reached before netplan-configured interfaces
  are online

Status in netplan.io package in Ubuntu:
  Fix Released

Bug description:
  Hi,

  Running Ubuntu 24.04 with netplan.io/netplan-generator 1.0-2ubuntu1.

  I use a systemd unit to mount an NFS filesystem. That unit should only
  be activated when the network is ready. However, it looks like
  network-online.target is reached before netplan-configured interfaces
  are up, so the unit triggers too early and sometimes fail (because it
  cannot resolve the name of the remote server).

  I configured netplan manually with:
  ```
  # cat /etc/netplan/01-netcfg.yaml 
  ---
  network:
    version: 2
    renderer: networkd
    ethernets:
      eno1:
        dhcp4: true
  ```

  I see the following during boot:

  ```
  Apr 27 23:31:28 localhost systemd[1]: Starting systemd-networkd.service - Network Configuration...
  Apr 27 23:31:28 localhost systemd-networkd[1190]: lo: Link UP
  Apr 27 23:31:28 localhost systemd-networkd[1190]: lo: Gained carrier
  Apr 27 23:31:28 localhost systemd-networkd[1190]: Enumeration completed
  Apr 27 23:31:28 localhost systemd-networkd[1190]: eno1: Configuring with /run/systemd/network/10-netplan-eno1.network.
  Apr 27 23:31:28 localhost systemd[1]: Started systemd-networkd.service - Network Configuration.
  Apr 27 23:31:28 localhost systemd[1]: Reached target network.target - Network.
  Apr 27 23:31:28 localhost systemd[1]: systemd-networkd-wait-online.service - Wait for Network to be Configured was skipped because of an unmet condition check (ConditionPathIsSymbolicLink=/run/systemd/generator/network-online.target.wants/systemd-networkd-wait-online.service).
  Apr 27 23:31:28 localhost systemd[1]: Reached target network-online.target - Network is Online.
  Apr 27 23:31:28 localhost systemd[1]: Reached target remote-fs-pre.target - Preparation for Remote File Systems.
  Apr 27 23:31:28 localhost systemd[1]: Mounting grid5000.mount - /grid5000...
  Apr 27 23:31:28 localhost systemd-networkd[1190]: eno1: Link UP
  Apr 27 23:31:28 localhost systemd-networkd[1190]: eno1: Gained carrier
  Apr 27 23:31:28 localhost systemd-networkd[1190]: eno1: DHCPv4 address 172.16.66.53/20, gateway 172.16.79.254 acquired from 172.16.79.107
  Apr 27 23:31:28 localhost systemd[1]: Starting networkd-dispatcher.service - Dispatcher daemon for systemd-networkd...
  Apr 27 23:31:29 gros-53 systemd[1]: Starting rpc-statd.service - NFS status monitor for NFSv2/3 locking....
  Apr 27 23:31:29 gros-53 rpc.statd[1439]: Version 2.6.4 starting
  Apr 27 23:31:29 gros-53 rpc.statd[1439]: Flags: TI-RPC
  Apr 27 23:31:29 gros-53 rpc.statd[1439]: Failed to read /var/lib/nfs/state: Success
  Apr 27 23:31:29 gros-53 rpc.statd[1439]: Initializing NSM state
  Apr 27 23:31:29 gros-53 systemd[1]: Started rpc-statd.service - NFS status monitor for NFSv2/3 locking..
  Apr 27 23:31:29 gros-53 mount[1441]: Created symlink /run/systemd/system/remote-fs.target.wants/rpc-statd.service → /usr/lib/systemd/system/rpc-statd.service.
  Apr 27 23:31:29 gros-53 systemd[1]: Reloading requested from client PID 1441 ('systemctl') (unit grid5000.mount)...
  Apr 27 23:31:29 gros-53 systemd[1]: Reloading...
  Apr 27 23:31:30 gros-53 systemd[1]: Reloading finished in 194 ms.
  Apr 27 23:31:30 gros-53 systemd[1]: Mounted grid5000.mount - /grid5000.
  Apr 27 23:31:30 gros-53 nfsrahead[1497]: setting /grid5000 readahead to 128

  
  The key message here seems to be:
  Apr 27 23:31:28 localhost systemd[1]: systemd-networkd-wait-online.service - Wait for Network to be Configured was skipped because of an unmet condition check (ConditionPathIsSymbolicLink=/run/systemd/generator/network-online.target.wants/systemd-networkd-wait-online.service).
  Why doesn't netplan generate that symlink? It seems it does generate it, but only later, when systemd reloads at 23:31:29 (according to 'stat' on the symlink).

  
  It worked fine with Ubuntu 22.04:
  "systemd[1]: Reached target Network is Online."
  only appears after the interface got configured via DHCP.

  ProblemType: Bug
  DistroRelease: Ubuntu 24.04
  Package: netplan.io 1.0-2ubuntu1
  ProcVersionSignature: Ubuntu 6.8.0-31.31-generic 6.8.1
  Uname: Linux 6.8.0-31-generic x86_64
  ApportVersion: 2.28.1-0ubuntu2
  Architecture: amd64
  CasperMD5CheckResult: pass
  Date: Sat Apr 27 23:50:37 2024
  InstallationDate: Installed on 2024-04-26 (1 days ago)
  InstallationMedia: Ubuntu-Server 24.04 LTS "Noble Numbat" - Release amd64 (20240423)
  ProcEnviron:
   LANG=en_US.UTF-8
   PATH=(custom, no user)
   SHELL=/bin/bash
   TERM=xterm
   XDG_RUNTIME_DIR=<set>
  SourcePackage: netplan.io
  UpgradeStatus: No upgrade log present (probably fresh install)

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