[Bug 838968] Re: static-network-up event does not wait for interfaces to have an address

[Steve Langasek]

Discussed on IRC, the problem here is that ifupdown invokes dhclient in
a way that it still exits with success when it has *failed* to acquire
an IP address, causing ifupdown to emit the interface-up event.

Passing -1 to dhclient3 gives the correct behavior: daemonize when an
address is acquired, and if the timeout is reached without acquiring an
address, exit non-zero instead of daemonizing.

There's a question of whether we should also raise the timeout in
dhclient to accomodate systems like the one where this was first
encountered, where 60 seconds isn't long enough to get the interface up
and get an address via dhcp; but at least the ifupdown change is a per-
se-correct one-line fix.

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Title:
  static-network-up event does not wait for interfaces to have an
  address

Status in “ifupdown” package in Ubuntu:
  New

Bug description:
  cloud-init's /etc/init/cloud-init-nonet.conf is configured to block
  running of cloud-init.conf until "static-network-up" is emitted.

  The point of that event was to wait until interfaces were all
  configured, and thus the network available.

  In practice, what I'm seeing is that for dhcp interfaces configured like:
     # The primary network interface
     auto eth0
     iface eth0 inet dhcp

  ifupdown runs /etc/network/if-up.d/upstart immediately upon forking
  off dhclient.

  
  $ ls -ld --full-time /var/run/network/static-network-up-emitted
  drwxr-xr-x 2 root root 40 2011-09-01 12:21:26.778833999 -0400 /var/run/network/static-network-up-emitted

  Then, in /var/log/syslog, the first non-kernel messages for this boot start at 12:21:28.  relevant dhcp messages are:
  Sep  1 12:21:29 mabolo dhclient: DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 7
  Sep  1 12:21:30 mabolo kernel: [   10.885045] bnx2 0000:02:00.0: eth0: NIC Copper Link is Up, 1000 Mbps full duplex
  Sep  1 12:21:30 mabolo kernel: [   10.886232] ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
  Sep  1 12:21:36 mabolo dhclient: DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 13
  ...
  Sep  1 12:22:13 mabolo dhclient: DHCPDISCOVER on eth0 to 255.255.255.255 port 67 interval 14
  Sep  1 12:22:13 mabolo dhclient: DHCPOFFER of 10.55.55.5 from 10.55.55.7
  Sep  1 12:22:13 mabolo dhclient: DHCPREQUEST of 10.55.55.5 on eth0 to 255.255.255.255 port 67
  Sep  1 12:22:14 mabolo dhclient: DHCPACK of 10.55.55.5 from 10.55.55.7
  Sep  1 12:22:14 mabolo dhclient: can't create /var/lib/dhcp3/dhclient.eth0.leases: No such file or directory
  Sep  1 12:22:14 mabolo dhclient: bound to 10.55.55.5 -- renewal in 1399 seconds.

  
  So it would surely appear that the event is happening immediately.
  However, to test this theory, I put the following into /etc/network/if-up.d/myfootest, and set up 'eth1' in /etc/network/interfaces.. (I knew that there would be no response on eth1's interface.)
  #!/bin/sh

  (
  echo "===== $(date -R) ====="
  echo "IFACE=$IFACE LOGICAL=$LOGICAL ADDRFAM=$ADDRFAM METHOD=$METHOD MODE=$MODE PHASE=$PHASE"
  ifconfig $IFACE
  )  | tee -a /var/log/myfoo.log

  exit 0

  
  Then, i ran 'sudo ifup eth1' and that took almost exactly 1 minute before writing the log and to the screen.  One difference  between the two is that eth1 is not attached to a device per ethtool.

  ProblemType: Bug
  DistroRelease: Ubuntu 11.10
  Package: ifupdown 0.7~alpha5.1ubuntu3
  ProcVersionSignature: User Name 3.0.0-9.15-virtual 3.0.3
  Uname: Linux 3.0.0-9-virtual i686
  Architecture: i386
  Date: Thu Sep  1 17:02:21 2011
  Ec2AMI: ami-00000070
  Ec2AMIManifest: FIXME
  Ec2AvailabilityZone: nova
  Ec2InstanceType: m1.small
  Ec2Kernel: unavailable
  Ec2Ramdisk: unavailable
  ProcEnviron:
   LANG=en_US.UTF-8
   SHELL=/bin/bash
  SourcePackage: ifupdown
  UpgradeStatus: No upgrade log present (probably fresh install)

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