ephemeral/enlistment nodes should dhcp with correct hostname

[Scott Moser]

Note: This bug has been changed to maas as a project, and its implementation changed significantly. See the original bug report below.

Instead of having hostname.conf read a kernel parameter, I've validated via packet inspection that at least in quantal, klibc's ipconfig seems to correctly send hostname as whatever is provided on the cmdline.

The format is:
 ip=::::<hostname>

| It would be nice if /etc/init/hostname.conf allowed the kernel cmdline to
| override the value in /etc/hostname. This is useful in the netboot case
| where the kernel cmdline can be controlled on a per MAC basis, but the
| filesystem is read-only.

| At this point I'm looking for input on possible fallout of a change like
| this.

| Here is the suggested /etc/init/hostname.conf:
| #
| # This task is run on startup to set the system hostname from /etc/hostname,
| # falling back to "localhost" if that file is not readable or is empty and
| # no hostname has yet been set.
| description "set system hostname"
| start on startup
| task
| script
|  { read cmdline < /proc/cmdline || : } >/dev/null 2>&1
|  if hn="${cmdline#*hostname=}" && [ "$hn" != "${cmdline}" ]; then
|     hn="${hn%% *}"
|     echo "setting hostname ${hn}" >/dev/console
|     exec hostname "${hn}"
|  fi
|  exec hostname -b -F /etc/hostname
|end script

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: hostname 3.11ubuntu1
ProcVersionSignature: Ubuntu 3.5.0-13.14-generic 3.5.3
Uname: Linux 3.5.0-13-generic x86_64
ApportVersion: 2.5.1-0ubuntu4
Architecture: amd64
Date: Wed Sep 5 11:53:36 2012
EcryptfsInUse: Yes
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
ProcEnviron:
 TERM=xterm
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: hostname
UpgradeStatus: Upgraded to quantal on 2011-11-07 (303 days ago)

[Scott Moser (smoser)]

I discussed this with slangasek in #ubuntu-devel today, and he preferred not to have this in /etc/init/hostname.conf as it does incur a for for the shell, and can be done elsewhere.

http://irclogs.ubuntu.com/2012/09/05/%23ubuntu-devel.html#t16:57

[Scott Moser (smoser)]

I came across this:
 http://www.kernel.org/doc/Documentation/frv/booting.txt

| (*) ip=<ip>::::<host>:<iface>:<cfg>
|
| Configure the network interface. If <cfg> is "off" then <ip> should
| specify the IP address for the network device <iface>. <host> provide
| the hostname for the device.
|
| If <cfg> is "bootp" or "dhcp", then all of these parameters will be
| discovered by consulting a BOOTP or DHCP server.
|
| For example, the following might be used:
|
| ip=192.168.73.12::::frv:eth0:off
|
| This sets the IP address on the VDK motherboard RTL8029 ethernet chipset
| (eth0) to be 192.168.73.12, and sets the board's hostname to be "frv".

So its possible we can already do this.

[Scott Moser (smoser)]

and also http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=367301

[Scott Moser (smoser)]

This went in under revno 1002.

[Scott Moser (smoser)]

Note, this change caused regression in multi-device systems (bug 1052660) and is being reverted.
For at least temporarily, we will move back to 'ip=dhcp'
https://code.launchpad.net/~smoser/maas/lp1052660/+merge/125046

[Scott Moser (smoser)]

I moved this back to 'Confirmed' as I backed the change out.

[Scott Moser (smoser)]

I've just added a package named 'cloud-initramfs-dyn-netconf' to the cloud-initramfs-tools package.
We'll utilize this package to fix this bug in the following manner.
 * add cloud-initramfs-dyn-netconf to the ephemeral images
 * boot with cmdline including 'ip=::::<hostname>:BOOTIF' and 'BOOTIF=MA:CA:DD:RE:SS'
 * cloud-initramfs-dyn-netconf will change the string 'BOOTIF' in the ip= to the actual interface name that is found on the system to have the provided BOOTIF.
 * open-iscsi's initramfs package will then call 'configure_networking' which will use the modified value of ip=.