[Bug 1905472] Re: Something starts dhcclient for every intrface on boot

[Andrey Lelikov]

This has nothing to do with network, as mentioned earlier netplan is
masked and ifupdown works as expected. Moreover it is known EXACTLY what
happens (in initramfs):

local_top/aoe calls configure_networking

In absence of any kernel args, configure_networking tries to bring up
every interface, by launching dhcpc for 3(?) seconds. This succeeds for
interface that will be configured as part of bridge by ifupdown later,
so bridge is left unconfigured and network is lost.

The current workaround is to add ip=none to kernel line

The proper fix is to change configure_networking to have a mode/arg
where it brings up network interfaces bot does not try to assign ip
addresses, and call it this way from local_top/aoe . Probably even split
configure_networking into two functions...

p.s. I can predict the future though (I have such a gift) - the
resolution would be "AOE is used by 0.000000000000000001% of ubuntu
users, we power the word and store petabytes of data, mark this as
enhancement for a future version N+5".

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https://bugs.launchpad.net/bugs/1905472

Title:
  Something starts dhcclient for every intrface on boot

Status in ifupdown package in Ubuntu:
  Incomplete
Status in initramfs-tools package in Ubuntu:
  Incomplete
Status in netplan.io package in Ubuntu:
  Incomplete

Bug description:
  After upgrade frpm 18LTS to 20LTS I've lost the network.

  Network is managed by ifupdown
  Netplan is not installed
  Network manger is disabled (masked)

  Yet, at boot, SOMETHING starts dhclient for every network interface.
  This has disastrous results - dhcp request succeeds on physical
  interface that is a base for a vlan-based interface, causing real dhcp
  request on to fail on vlan interface.

  Expected behavior - dhclient starts only for interfaces marked as dhcp
  in /etc/network/interfaces .

  ProblemType: Bug
  DistroRelease: Ubuntu 20.04
  Package: isc-dhcp-client 4.4.1-2.1ubuntu5
  ProcVersionSignature: Ubuntu 5.8.0-29.31~20.04.1-generic 5.8.14
  Uname: Linux 5.8.0-29-generic x86_64
  NonfreeKernelModules: nvidia_modeset nvidia
  ApportVersion: 2.20.11-0ubuntu27.12
  Architecture: amd64
  CasperMD5CheckResult: skip
  Date: Wed Nov 25 00:07:45 2020
  SourcePackage: isc-dhcp
  UpgradeStatus: No upgrade log present (probably fresh install)

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