[Bug 974284] [NEW] invoking dhclient3 with -1 causes issue if no dhcp server available

[Scott Moser]

Public bug reported:

In bug 838968, we modified ifupdown to invoke dhclient3 with '-1' as a
parameter [1], and subsequently changed the default timeout of dhclient
in isc-dhcp3 to from 60 seconds to 300 seconds [2].

The reason for this is that we now have a reliable "static-networking-
up" event that can be used for upstart jobs to start on, when static
networking is up.  Here, static is any networking with an entry in
/etc/network/interfaces.

That event is used by cloud-init and other things that depend on
network.

The fallout of this is that if for some reason a server (or cloud-
instance, or anything really), boots and does not obtain a dhcp address
in 5 minutes, then it will give up forever.  The previous behavior is
that it would try forever.

This scenario isn't terribly unrealistic.  A power fail could take out a
dchp server, cause a fsck, while the server came up 5 minutes before the
dhcp server was up.


--
[1] http://bazaar.launchpad.net/~ubuntu-branches/ubuntu/precise/ifupdown/precise/revision/56
[2] http://bazaar.launchpad.net/~ubuntu-branches/ubuntu/precise/isc-dhcp/precise/revision/32

Releated bugs:
  * bug 838968: static-network-up event does not wait for interfaces to have an address

** Affects: ifupdown (Ubuntu)
     Importance: Undecided
         Status: New

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https://bugs.launchpad.net/bugs/974284

Title:
  invoking dhclient3 with -1 causes issue if no dhcp server available

Status in “ifupdown” package in Ubuntu:
  New

Bug description:
  In bug 838968, we modified ifupdown to invoke dhclient3 with '-1' as a
  parameter [1], and subsequently changed the default timeout of
  dhclient in isc-dhcp3 to from 60 seconds to 300 seconds [2].

  The reason for this is that we now have a reliable "static-networking-
  up" event that can be used for upstart jobs to start on, when static
  networking is up.  Here, static is any networking with an entry in
  /etc/network/interfaces.

  That event is used by cloud-init and other things that depend on
  network.

  The fallout of this is that if for some reason a server (or cloud-
  instance, or anything really), boots and does not obtain a dhcp
  address in 5 minutes, then it will give up forever.  The previous
  behavior is that it would try forever.

  This scenario isn't terribly unrealistic.  A power fail could take out
  a dchp server, cause a fsck, while the server came up 5 minutes before
  the dhcp server was up.

  
  --
  [1] http://bazaar.launchpad.net/~ubuntu-branches/ubuntu/precise/ifupdown/precise/revision/56
  [2] http://bazaar.launchpad.net/~ubuntu-branches/ubuntu/precise/isc-dhcp/precise/revision/32

  Releated bugs:
    * bug 838968: static-network-up event does not wait for interfaces to have an address

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