[Bug 2065037] Re: dhcpcd is called before interfaces have carrier causing a 29 seconds boot delay

[Andreas Hasenack]

I retried the failing armhf dep8 tests and they are now green.

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https://bugs.launchpad.net/bugs/2065037

Title:
  dhcpcd is called before interfaces have carrier causing a 29 seconds
  boot delay

Status in initramfs-tools package in Ubuntu:
  Fix Released
Status in initramfs-tools source package in Noble:
  Fix Committed

Bug description:
  [ Impact ]

  The boot time can be longer on system that configure their network in
  the initrd.

  [ Test Plan ]

  The affected systems show "Sleeping $time seconds before retrying
  getting a DHCP lease" in their boot log. Once applying the fix, this
  message should not be found any more and "dhcpcd-10.0.6 starting"
  should be only logged once (at most once for IPv4 and once for IPv6
  depending on the boot parameters).

  There are qemu-net and qemu-net-dnsmasq autopkgtests for this area of
  code.

  [ Where problems could occur ]

  The DHCP code in the initrd are touched. So the boot can be affected.
  Also updating initramfs-tools will regenerate the initrd and can cause
  issues there (like full disks, etc).

  [ Original report ]

  In automatically encrypted Clevis+Tang unlock of LUKS encrypted device
  (dmcrypt/cryptsetup) - on top of which the ZFS Pool for / resides,
  dhcpcd is used in order to obtain automatically an IP address during
  initramfs boot.

  During this phase, dhcpcd is called before interfaces have carrier
  causing a 29 seconds boot delay.

  Boot delay is currently 45 seconds, instead of the 15 seconds that it
  should.

  BUG Initially reported in:
  https://bugs.launchpad.net/ubuntu/+source/initramfs-tools/+bug/2064926

  Relevant Logs:
  ```
  dhcpcd-10.0.6 starting
  [...]
  no interfaces have a carrier
  exiting due to oneshot
  dhcpcd exited
  Sleeping 29 seconds before retrying getting a DHCP lease
  dhcpcd-10.0.6 starting
  ```

  A possible workaround would be to manually edit /usr/share/initramfs-tools/scripts/functions
  Changing this:
  `for ROUNDTTT in 30 60 90 120; do`

  To this:
  `for ROUNDTTT in 5 5 5 5; do`

  But the proper solution would be to continuously "scan" the state of
  the Interface (every Second or so), and wait until the interface is
  UP, before deciding to call dhcpcd.

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