[Bug 1750597] Re: PXE netboot install of Ubuntu Desktop results in unconfigured network interface

[Brian Murray]

** Package changed: casper (Ubuntu) => debian-installer (Ubuntu)

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Title:
  PXE netboot install of Ubuntu Desktop results in unconfigured network
  interface

Status in debian-installer package in Ubuntu:
  New

Bug description:
  When doing a PXE netboot of Ubuntu Desktop over NFS, the installer
  adds the following lines for each network interface to
  /etc/network/interfaces (I think this is to keep the root fs available
  during the live session):

    auto ens3
    iface ens3 inet manual

  I was able to reproduce the issue with both Xenial and Bionic. There's
  something specific about Ubuntu Desktop that's not an issue with
  Ubuntu Server. I believe it's because of ubiquity and casper being
  used for Desktop vs debian installer in Server.

  The workaround is to edit /etc/network/interfaces and remove the lines
  relating to your network interfaces after rebooting at the end of the
  installation. The only two non-comment lines left when you’re finished
  should be:

  auto lo 
  iface lo inet loopback 

  One can preseed a late_command which overwrites the
  /etc/network/interfaces with only a loopback device to automate this
  workaround.

  There is an 8 year old bug #388060 related to this issue that mentions
  the following:

  ```
  These lines are added by casper in a script called 23networking. Here are a few relevant lines from the script: 

  if [ -z "${NETBOOT}" ]; then method="dhcp"; else method="manual"; fi 
  if [ "$method" != dhcp ] || [ ! -x /root/usr/sbin/NetworkManager ]; then 
  # ... 
  cat >> "$IFFILE" <<EOF 
  auto $i 
  iface $i inet $method 

  EOF 
  fi 

  So, this at least enables the live cd environment to be loaded over
  NFS. However, the problem is that this later gets propagated to the
  installed environment if ubiquity is called. This is done by the
  install.py script and here are the relevant lines from the script:

  for path in ('/etc/network/interfaces', '/etc/resolv.conf'): 
  if os.path.exists(path): 
  shutil.copy2(path, os.path.join(self.target, path[1:])) 
  ```

  I'm attaching a screenshot of the issue after the livecd netboot PXE
  installation (netboot-pxe-issue.png) and another screenshot of the
  same instance but after the workaround to remove the lines in /e/n/i
  (netboot-pxe-issue-after-workaround.png).

  Additional information:

  1) The release of Ubuntu you are using via 'lsb_release -rd'

  Ubuntu 16.04.3 LTS
  Ubuntu Bionic Beaver (development branch)

  2) The version of the package you are using, via 'apt-cache policy
  pkgname'

  Ubuntu 16.04.3 LTS:
  casper 1.376.2
  ubiquity 2.21.63.4

  Ubuntu Bionic Beaver (development branch)
  casper 1.388
  ubiquity 18.04.1

  
  3) What you expected to happen
  Network interfaces should be configured by Network Manager after the final reboot at the end of the installation. There shouldn't be 'manual' lines in /etc/network/interfaces at the end of the installation.

  
  4) What happened instead
  Network interfaces are not configured by Network Manager after the final reboot at the end of the installation. There are 'manual' lines in /etc/network/interfaces at the end of the installation and because of that there is no network interface configured after the reboot.

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