Adding and deleting a veth leaks a systemd unit

[Shaun Crampton]

When I add a veth device:

    sudo ip link add name test1 type veth

I see these systemd units appear:

    systemctl list-units --all | grep test

     sys-devices-virtual-net-test1.device
             loaded active plugged /sys/devices/virtual/net/test1

     sys-subsystem-net-devices-test1.device
             loaded active plugged /sys/subsystem/net/devices/test1

However, if I then delete the veth:

    sudo ip link del dev test1

Then only one of the units is removed:

    systemctl list-units --all | grep test

      sys-devices-virtual-net-test1.device
             loaded active plugged /sys/devices/virtual/net/test1

This is a big problem when running, for example, a Kubernetes cluster since each pod creation/deletion leaks a systemd unit. When enough have been leaked, systemd becomes unresponsive and the system is broken until reboot.

ProblemType: Bug
DistroRelease: Ubuntu 17.10
Package: systemd 234-2ubuntu12.1
ProcVersionSignature: Ubuntu 4.13.0-21.24-generic 4.13.13
Uname: Linux 4.13.0-21-generic x86_64
ApportVersion: 2.20.7-0ubuntu3.6
Architecture: amd64
Date: Tue Jan 9 18:57:34 2018
Lsusb: Error: command ['lsusb'] failed with exit code 1:
MachineType: Google Google Compute Engine
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.13.0-21-generic root=UUID=c66b8cf4-2a6c-4fb3-9f39-59483a6a025c ro scsi_mod.use_blk_mq=Y console=ttyS0
SourcePackage: systemd
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 01/01/2011
dmi.bios.vendor: Google
dmi.bios.version: Google
dmi.board.asset.tag: 1AF4A7E8-D62B-D331-0693-3511A041DD96
dmi.board.name: Google Compute Engine
dmi.board.vendor: Google
dmi.chassis.type: 1
dmi.chassis.vendor: Google
dmi.modalias: dmi:bvnGoogle:bvrGoogle:bd01/01/2011:svnGoogle:pnGoogleComputeEngine:pvr:rvnGoogle:rnGoogleComputeEngine:rvr:cvnGoogle:ct1:cvr:
dmi.product.name: Google Compute Engine
dmi.sys.vendor: Google

[Shaun Crampton (fasaxc)]

As a workaround, running

    systemctl daemon-reload

removes all the leaked units.

[Shaun Crampton (fasaxc)]

I tried this on Ubuntu 16.04, started on GCE and it didn't seem to repro there. When I add a veth, systemd units are added but they all seem to be cleaned up when the veth is removed.

[Dan Streetman (ddstreet)]

please reopen if this is still an issue