touch-packages team mailing list archive

[Scott Moser <smoser@xxxxxxxxxx>]

## host system is vivid, trusty would also do

host $ rel=trusty ; serial=20150417
host $ url=http://cloud-images.ubuntu.com/releases/$rel/release-$serial/ubuntu-14.04-server-cloudimg-amd64-disk1.img
host $ img_dist="$rel-$serial-amd64.img.dist"
host $ img=${img_dist%.dist}

host $ pkgs="qemu-utils qemu-system-x86 cloud-image-utils"
host $ sudo apt-get --assume-yes install $pkgs

## get images and convert qcow to raw
host $ [ -f "$img_dist" ] ||
  { wget "$url" -O "$img_dist.tmp" && mv "$img_dist.tmp" "$img_dist"; }
host $ [ -f "$img" ] ||
   { qemu-img convert -O raw "$img_dist" "$img.tmp" && mv "$img.tmp" "$img"; }

## create a user-data to let you log in
host $ cat > user-data <<EOF 
#cloud-config
password: passw0rd
chpasswd: { expire: False }
ssh_pwauth: True
EOF
host $ cloud-localds seed.img user-data

## launch a guest with 2 nics, one stable/ssh in, one for testing
## you can ssh in with 'ubuntu/passw0rd' with 'ssh -p 2222 ubuntu@localhost'
host $ qemu-img create -f qcow2 -b $img disk.img
host $ qemu-system-x86_64 -enable-kvm \
   -device virtio-net-pci,netdev=net00 \
   -netdev user,id=net00,hostfwd=tcp::2222-:22 \
   -device virtio-net-pci,netdev=net01 \
   -netdev user,id=net01 \
   -drive if=virtio,file=disk.img,if=virtio \
   -drive if=virtio,file=seed.img,if=virtio \
   -m 768 -curses

## have 2 windows / shells in system.
### setup system
guest $ crazy_url=http://bazaar.launchpad.net/~smoser/+junk/lp1444428/download/head:/nicgocrazy-20150421193756-8xtcmllz0qf4efb4-2/nic-go-crazy
guest $ $ loop_url=http://bazaar.launchpad.net/~smoser/+junk/lp1444428/download/head:/ifuploop-20150421193756-8xtcmllz0qf4efb4-1/ifup-loop

guest $ wget "$crazy_url" -O nic-go-crazy
guest $ wget "$loop_url" -O loop-ifup
guest $ chmod 755 nic-go-crazy loop-ifup
guest $ echo "iface eth1 inet dhcp" | sudo tee -a /etc/network/interfaces

### recreate failure ####
guest-w1 % sudo ./nic-go-crazy 20 nicfoo
guest-w2 % sudo ./loop-ifup
Internet Systems Consortium DHCP Client 4.2.4
Copyright 2004-2012 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/

Error getting interface address for 'nic074725'; No such device
Error getting interface information.
Failed to bring up eth1.

### enable proposed and get update ###
guest $ rel=$(lsb_release -sc)
guest $ echo "deb http://archive.ubuntu.com/ubuntu ${rel}-proposed main" |
   sudo tee -a /etc/apt/sources.list.d/proposed.list
guest $ sudo apt-get update --quiet
guest $ sudo apt-cache policy 
guest $ sudo apt-cache policy isc-dhcp-client
isc-dhcp-client:
  Installed: 4.2.4-7ubuntu12.1
  Candidate: 4.2.4-7ubuntu12.2
  Version table:
     4.2.4-7ubuntu12.2 0
        500 http://archive.ubuntu.com/ubuntu/ trusty-proposed/main amd64 Packages
 *** 4.2.4-7ubuntu12.1 0
        500 http://archive.ubuntu.com/ubuntu/ trusty-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     4.2.4-7ubuntu12 0
        500 http://archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages

guest $ sudo apt-get install isc-dhcp-client -qy

## retry the 'recreate failure' test above. It should run indefinintely.

-- 
You received this bug notification because you are a member of Ubuntu
Touch seeded packages, which is subscribed to isc-dhcp in Ubuntu.
https://bugs.launchpad.net/bugs/1446767

Title:
  dhclient can fail if other nics are renamed

Status in isc-dhcp package in Ubuntu:
  Fix Committed
Status in isc-dhcp source package in Trusty:
  Fix Committed
Status in isc-dhcp source package in Vivid:
  Fix Committed
Status in isc-dhcp source package in Wily:
  Triaged
Status in isc-dhcp package in Fedora:
  Unknown

Bug description:
  === Begin SRU Information ===
  [Impact] 
  Systems that use dhcp for network config combined with network device re-naming can hit a race condition in dhclient which causes dhcp to fail.  Any network device renaming could cause this, but the most likely scenario is boot with udev persistent naming in /etc/udev/rules.d/70-persistent-net.rules.

  This can be a fatal error when network devices that are required for
  proper function.

  [Test Case]
  To recreate the failure:
   * boot an ubuntu system with an interface that can dhcp
   * configure /etc/network/interfaces for dhcp on that interface
     $ grep eth0 /etc/network/interfaces
     auto eth0
     iface eth0 inet dhcp
   * run attached 'nic-go-crazy' as root in one window/shell
     this will create by default 10 tuntap devices and repeatedly rename them.
   * run attached 'ifup-loop eth0'

  ifup-loop will exit failure if dhclient failed to bring the network
  up.

  With the fix provided, this will/should run indefinitely.

  [Regression Potential]
  Chance for regression here should be reasonably small.  However, a very significant number of systems run dhclient, so any change has to be considered risky.

  One thing to note, is that Fedora has carried this patch for > 3
  years.

  Per getifaddrs(3):
   | The getifaddrs() function first appeared in glibc 2.3, but before glibc
   | 2.3.3, the implementation supported only IPv4 addresses; IPv6 support
   | was added in glibc 2.3.3. Support of address families other than IPv4
   | is available only on kernels that support netlink.

  These versions are older than any supported Ubuntu release, so that should not be a problem.
  === End SRU Information ===

  
  given 3 nics eth0, eth1, eth2

  dhclient -1 -v -pf /run/dhclient.eth0.pid -lf
  /var/lib/dhcp/dhclient.eth0.leases eth0

  while that in its early phases, if eth1 is renamed a race condition
  can cause dhclient to exit failure.

  This can happen in real life when udev and persistent rules are used.
  Ie, in a system where eth0 is configured for 'auto' and dhcp  and
  persistent rules cause renaming of devices during boot.

  I have set up recreate of that more complex system
  lp:~smoser/+junk/lp1444428 , but this recreate is simpler to catch.

  example, while running attached 'nic-go-crazy' on other nics, I try
  ifup eth1

  $ sudo ifup eth1
  sudo: unable to resolve host ubuntu
  Internet Systems Consortium DHCP Client 4.3.1
  Copyright 2004-2014 Internet Systems Consortium.
  All rights reserved.
  For info, please visit https://www.isc.org/software/dhcp/

  Error getting interface address for 'nic0317610'; No such device
  Error getting interface information.

  If you think you have received this message due to a bug rather
  than a configuration issue please read the section on submitting
  bugs on either our web page at www.isc.org or in the README file
  before submitting a bug.  These pages explain the proper
  process and the information we find helpful for debugging..

  exiting.
  Failed to bring up eth1.

  ProblemType: Bug
  DistroRelease: Ubuntu 15.04
  Package: isc-dhcp-client 4.3.1-5ubuntu2
  ProcVersionSignature: User Name 3.19.0-15.15-generic 3.19.3
  Uname: Linux 3.19.0-15-generic x86_64
  ApportVersion: 2.17.2-0ubuntu1
  Architecture: amd64
  Date: Tue Apr 21 16:35:10 2015
  DhclientLeases:

  ProcEnviron:
   TERM=screen
   PATH=(custom, no user)
   XDG_RUNTIME_DIR=<set>
   LANG=en_US.UTF-8
   SHELL=/bin/bash
  SourcePackage: isc-dhcp
  UpgradeStatus: No upgrade log present (probably fresh install)

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