[Bug 1631474] Re: No networking with initramfs-tools 0.122ubuntu8.3 and ip=dhcp boot option

[Scott Moser]

Hi,
I think the right way to fix this regression would have been to revert the change.
The change made in bug 1628306 made fairly wide spread changes.  It caused this regression as seen, but also added behavioral changes.

Previously, 'ip=dhcp' would do a ipv4 dhcp request (via ipconfig).
The change was:
a.) to make it use dhclient
b.) to *also* do a dhcpv6 request in all cases.


** Description changed:

  [Impact]
  
   * 0.122ubuntu8.3 of initramfs-tools no longer correctly processed
  ip=dhcp or ip=:::::eth0:dhcp
  
   * Regression-updates
  
   * The fix better parses the ip= command line argument.
  
  [Test Case]
  
   * Create a machine that boots using an nfsroot.
  
   * Use ip=:::::eth0:dhcp on the kernel command line.  To set up
     networking.
  
   * Discover that the device never comes up because, networking is not
  configured correctly.
  
  [Regression Potential]
  
   * Regressions potential is limited to machines using
  ip={""|::::*|on|any|dhcp} on the kernel command line.  As this is
  already broken regression potential is minimal.  This is common on
  machines that use nfsroot or otherwise pxe boot.
  
  [Other Info]
  
-  * There are a number of other issues in this code base that are not solved by this fix. 
-    - The ?*:?*:?*:?*: use case falls through to the default case, and likely breaks there.  As such static assignment via ip= appears broken 
-    - 
+  * There are a number of other issues in this code base that are not solved by this fix.
+    - The ?*:?*:?*:?*: use case falls through to the default case, and likely breaks there.  As such static assignment via ip= appears broken
+    -
   * The networking configuration does not strictly follow the kernel documentation as described https://www.kernel.org/doc/Documentation/filesystems/nfs/nfsroot.txt . This should be fixed.
+ 
+ This bug is a regression of changes made under bug 1628306.
  
  ====================Original Bug Description Follows==================
  
  initramfs-tools 0.122ubuntu8.3 introduced a serious regression where
  networking is not initialized when the boot option "ip=dhcp" is
  provided. We are seeing this problem in AWS, but cannot confirm if this
  issue is specific to AWS or will occur with different hardware or in
  different environments.
  
  Removing "ip=dhcp" from the boot options with 0.122ubuntu8.3 results in
  networking being configured.
  
  The issue does not occur with 0.122ubuntu8.2 or previous versions when
  "ip=dhcp" is set.
  
  AWS has no console so debugging is not a trivial task. I do have a
  console log with some output, and will update this bug shortly with it.

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https://bugs.launchpad.net/bugs/1631474

Title:
  No networking with initramfs-tools 0.122ubuntu8.3 and ip=dhcp boot
  option

Status in initramfs-tools package in Ubuntu:
  Fix Committed
Status in initramfs-tools source package in Xenial:
  Fix Committed
Status in initramfs-tools source package in Yakkety:
  Fix Committed
Status in initramfs-tools source package in z-series:
  Fix Committed

Bug description:
  [Impact]

   * 0.122ubuntu8.3 of initramfs-tools no longer correctly processed
  ip=dhcp or ip=:::::eth0:dhcp

   * Regression-updates

   * The fix better parses the ip= command line argument.

  [Test Case]

   * Create a machine that boots using an nfsroot.

   * Use ip=:::::eth0:dhcp on the kernel command line.  To set up
     networking.

   * Discover that the device never comes up because, networking is not
  configured correctly.

  [Regression Potential]

   * Regressions potential is limited to machines using
  ip={""|::::*|on|any|dhcp} on the kernel command line.  As this is
  already broken regression potential is minimal.  This is common on
  machines that use nfsroot or otherwise pxe boot.

  [Other Info]

   * There are a number of other issues in this code base that are not solved by this fix.
     - The ?*:?*:?*:?*: use case falls through to the default case, and likely breaks there.  As such static assignment via ip= appears broken
     -
   * The networking configuration does not strictly follow the kernel documentation as described https://www.kernel.org/doc/Documentation/filesystems/nfs/nfsroot.txt . This should be fixed.

  This bug is a regression of changes made under bug 1628306.

  ====================Original Bug Description Follows==================

  initramfs-tools 0.122ubuntu8.3 introduced a serious regression where
  networking is not initialized when the boot option "ip=dhcp" is
  provided. We are seeing this problem in AWS, but cannot confirm if
  this issue is specific to AWS or will occur with different hardware or
  in different environments.

  Removing "ip=dhcp" from the boot options with 0.122ubuntu8.3 results
  in networking being configured.

  The issue does not occur with 0.122ubuntu8.2 or previous versions when
  "ip=dhcp" is set.

  AWS has no console so debugging is not a trivial task. I do have a
  console log with some output, and will update this bug shortly with
  it.

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