[Bug 1841378] Re: MACVLAN= in .nspawn file vs command line results in /sys/class/net showing host interfaces

[Balint Reczey]

Fixed in 240 and up.

** Also affects: systemd (Ubuntu Bionic)
   Importance: Undecided
       Status: New

** Changed in: systemd (Ubuntu)
       Status: New => Fix Released

** Also affects: systemd (Ubuntu Disco)
   Importance: Undecided
       Status: New

** Changed in: systemd (Ubuntu Disco)
       Status: New => Fix Released

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Title:
  MACVLAN= in .nspawn file vs command line results in /sys/class/net
  showing host interfaces

Status in systemd package in Ubuntu:
  Fix Released
Status in systemd source package in Bionic:
  New
Status in systemd source package in Disco:
  Fix Released

Bug description:
  I have machine with the following nspawn file:

  --
  [Network]
  MACVLAN=laneth0

  [Exec]
  PrivateUsers=false
  --

  if I start it with systemctl start systemd-nspawn at name, all works as
  expected.

  If I start manually with systemd-nspawn -M name -b, I seem to
  correctly get a new network namespace (ip link output in container is
  correct), but ls /sys/class/net shows the host's interfaces.

  The difference turns out to be that starting with systemctl uses a
  default command line which includes --private-network; the MACVLAN= in
  the config file should imply this, but instead it seems I'm getting
  "half" a private network, with the namespace correctly set but /sys
  not.

  Having a quick poke around, I suspect

  https://github.com/systemd/systemd/commit/60f1ec13ed059e412c2a2ee4cc3093e2d520673c

  may have 'accidentally' fixed this - it moves

         if (arg_private_network)
                  arg_mount_settings |= MOUNT_APPLY_APIVFS_NETNS;

  from parse_argv to verify_arguments which is called later.

  This bug causes netplan to fail as well as it rummages around in
  /sys/class/net.

  If the planets ever align appropriately, I will try to come up with a
  patch to 237 for bionic, but I don't recommend anyone holds their
  breath..

  ProblemType: Bug
  DistroRelease: Ubuntu 18.04
  Package: systemd-container 237-3ubuntu10.25
  Uname: Linux 4.19.13-041913-generic x86_64
  ApportVersion: 2.20.9-0ubuntu7.6
  Architecture: amd64
  CurrentDesktop: XFCE
  Date: Sun Aug 25 17:54:50 2019
  InstallationDate: Installed on 2018-03-22 (521 days ago)
  InstallationMedia: Xubuntu 18.04 LTS "Bionic Beaver" - Alpha amd64 (20180306.1)
  SourcePackage: systemd
  UpgradeStatus: No upgrade log present (probably fresh install)

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