[Bug 1845239] [NEW] preseed/early_command doesn't work from kernel command line

[Andrew Kanaber]

Public bug reported:

Using the Ubuntu netboot installer as obtained from
http://archive.ubuntu.com/ubuntu/dists/bionic-updates/main/installer-
amd64/current/images/netboot/ubuntu-installer/amd64/ the installer fails
to run a preseed/early_command set from the kernel command line (added
to the menu entry in grub.cfg).

A precisely equivalent config does cause the command to run in Debian 10
and 9, so this appears to be a difference between Debian's version of
debian-installer and the one in Ubuntu. The preseeded command can be
made to work in Ubuntu if instead placed in a preseed.cfg inserted into
the initrd, so the issue appears to be specific to setting
preseed/early_command from the kernel commandline.

For example, setting only the following grub config options: (this is on
a Xen system)

    set root=(xen/xvdd,msdos1)
    linux /installer-ubuntu/18.04/linux "preseed/early_command=logger wibble"
    initrd /installer-ubuntu/18.04/initrd.gz      

and the interrupting the install, starting a shell and running 'grep
wibble /var/log/syslog' shows only the kernel commandline, whereas on
Debian 10 with the following grub config

    set root=(xen/xvdd,msdos1)
    linux /installer-debian/10/vmlinuz "preseed/early_command=logger wibble"
    initrd /installer-debian/10/initrd.gz

and again interrupting the install and running 'grep wibble /var/log/syslog' from the shell produces:
Sep 24 17:09:57 kernel: [    0.000000] Command line: "preseed/early_command=logger wibble"
Sep 24 17:09:57 kernel: [    0.412794] Kernel command line: "preseed/early_command=logger wibble"
Sep 24 17:09:57 preseed: running preseed command preseed/early_command: logger wibble
Sep 24 17:09:57 root: wibble

adding DEBCONF_DEBUG=5 to the kernel command line on Ubuntu and running
'egrep early_command\|wibble /var/log/syslog' produces: 
Sep 24 17:19:13 kernel: [    0.000000] Command line: "preseed/early_command=logger wibble" DEBCONF_DEBUG=5
Sep 24 17:19:13 kernel: [    0.000000] Kernel command line: "preseed/early_command=logger wibble" DEBCONF_DEBUG=5
Sep 24 17:19:14 frontend: --> GET preseed/early_command
Sep 24 17:19:14 frontend: --> SET preseed/early_command logger wibble
Sep 24 17:19:14 frontend: --> METAGET preseed/early_command type
Sep 24 17:19:14 frontend: --> FSET preseed/early_command seen true

So the preseed value does get picked up by debconf, it's just that the
installer never actually runs the command.

Thanks for your help,

** Affects: base-installer (Ubuntu)
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/1845239

Title:
  preseed/early_command doesn't work from kernel command line

Status in base-installer package in Ubuntu:
  New

Bug description:
  Using the Ubuntu netboot installer as obtained from
  http://archive.ubuntu.com/ubuntu/dists/bionic-updates/main/installer-
  amd64/current/images/netboot/ubuntu-installer/amd64/ the installer
  fails to run a preseed/early_command set from the kernel command line
  (added to the menu entry in grub.cfg).

  A precisely equivalent config does cause the command to run in Debian
  10 and 9, so this appears to be a difference between Debian's version
  of debian-installer and the one in Ubuntu. The preseeded command can
  be made to work in Ubuntu if instead placed in a preseed.cfg inserted
  into the initrd, so the issue appears to be specific to setting
  preseed/early_command from the kernel commandline.

  For example, setting only the following grub config options: (this is
  on a Xen system)

      set root=(xen/xvdd,msdos1)
      linux /installer-ubuntu/18.04/linux "preseed/early_command=logger wibble"
      initrd /installer-ubuntu/18.04/initrd.gz      

  and the interrupting the install, starting a shell and running 'grep
  wibble /var/log/syslog' shows only the kernel commandline, whereas on
  Debian 10 with the following grub config

      set root=(xen/xvdd,msdos1)
      linux /installer-debian/10/vmlinuz "preseed/early_command=logger wibble"
      initrd /installer-debian/10/initrd.gz

  and again interrupting the install and running 'grep wibble /var/log/syslog' from the shell produces:
  Sep 24 17:09:57 kernel: [    0.000000] Command line: "preseed/early_command=logger wibble"
  Sep 24 17:09:57 kernel: [    0.412794] Kernel command line: "preseed/early_command=logger wibble"
  Sep 24 17:09:57 preseed: running preseed command preseed/early_command: logger wibble
  Sep 24 17:09:57 root: wibble

  adding DEBCONF_DEBUG=5 to the kernel command line on Ubuntu and running
  'egrep early_command\|wibble /var/log/syslog' produces: 
  Sep 24 17:19:13 kernel: [    0.000000] Command line: "preseed/early_command=logger wibble" DEBCONF_DEBUG=5
  Sep 24 17:19:13 kernel: [    0.000000] Kernel command line: "preseed/early_command=logger wibble" DEBCONF_DEBUG=5
  Sep 24 17:19:14 frontend: --> GET preseed/early_command
  Sep 24 17:19:14 frontend: --> SET preseed/early_command logger wibble
  Sep 24 17:19:14 frontend: --> METAGET preseed/early_command type
  Sep 24 17:19:14 frontend: --> FSET preseed/early_command seen true

  So the preseed value does get picked up by debconf, it's just that the
  installer never actually runs the command.

  Thanks for your help,

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