[Bug 2039743] Re: Intermittent DHCP startup failure during boot due to potential race condition in interface renaming

[Nick Rosbrook]

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

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Title:
  Intermittent DHCP startup failure during boot due to potential race
  condition in interface renaming

Status in systemd package in Ubuntu:
  New
Status in systemd source package in Focal:
  New

Bug description:
  The server fails to start its network with DHCP seemingly randomly. It
  can take a few reboots to bring up the network. This causes issues
  where automated updates that trigger a reboot cause the server to go
  offline.

  I've attached syslog examples of both success and failure.

  My assumption is that the cause of this bug is a race condition where
  systemd is not waiting on the interface renaming.

  Notably, when it boots properly, it says:

  "Interface is under renaming, pending initialization."

  That message is not logged when it fails.

  The server uses cloud-init, and the cloud image provided by Ubuntu.

  Another possible explanation is the netplan configuration at
  /etc/netplan/50-cloud-init.yaml is:

  network:
      version: 2
      ethernets:
          eth0:
              dhcp4: true
              match:
                  macaddress: 92:00:00:00:43:6a
              set-name: eth0

  Maybe set-name is redundant here, but it's the default configuration
  generated by cloud-init.

  ProblemType: Bug
  DistroRelease: Ubuntu 20.04
  Package: systemd 245.4-4ubuntu3.21
  ProcVersionSignature: Ubuntu 5.4.0-164.181-generic 5.4.248
  Uname: Linux 5.4.0-164-generic x86_64
  ApportVersion: 2.20.11-0ubuntu27.27
  Architecture: amd64
  CasperMD5CheckResult: skip
  Date: Wed Oct 18 16:22:57 2023
  Lsusb: Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
  Lsusb-t: /:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=uhci_hcd/2p, 12M
  MachineType: Slicie.com Slicie Cloud Server
  ProcEnviron:
   TERM=xterm-256color
   PATH=(custom, no user)
   XDG_RUNTIME_DIR=<set>
   LANG=C.UTF-8
   SHELL=/bin/bash
  ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-5.4.0-164-generic root=UUID=f849f569-82f8-4fc0-9ac6-d4f7f7ef9609 ro console=tty1 console=ttyS0
  SourcePackage: systemd
  UpgradeStatus: No upgrade log present (probably fresh install)
  dmi.bios.date: 04/01/2014
  dmi.bios.vendor: SeaBIOS
  dmi.bios.version: 1.13.0-1ubuntu1.1
  dmi.chassis.type: 1
  dmi.chassis.vendor: QEMU
  dmi.chassis.version: pc-i440fx-2.1
  dmi.modalias: dmi:bvnSeaBIOS:bvr1.13.0-1ubuntu1.1:bd04/01/2014:svnSlicie.com:pnSlicieCloudServer:pvr1.0.0:cvnQEMU:ct1:cvrpc-i440fx-2.1:
  dmi.product.name: Slicie Cloud Server
  dmi.product.version: 1.0.0
  dmi.sys.vendor: Slicie.com

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