yahoo-eng-team team mailing list archive

[Brett Holman <1996789@xxxxxxxxxxxxxxxxxx>]

Public bug reported:

Currently when duplicate mac addresses are detected, cloud-init dies.

While duplicate macs are typically corner cases, there are cases when
they can be valid[1].

Consider this example[2]. After bonding two interfaces, the interfaces
were left with duplicate mac addresses. Using cloud-init on this system
fails at the time that these devices are detected.

If no network config is given, or if a config is given configuring a
single address, we have the opportunity to do something intelligent to
allow cloud-init to boot by using the "fallback interface" (in cloud-
init this is the first interface), rather than throwing an exception and
dying.

Netplan's mac matching assumes 1:1 mapping between mac addresses and
interfaces, so in the case of multiple interfaces configured with
matches, we still can't do anything intelligent.


[1] Until these have unique addresses, these interfaces will not be usable on the same broadcast domain, but they should still be able to work individually on different networks.
[2] https://stackoverflow.com/questions/74459180/deleted-bond-interface-left-me-with-duplicate-mac-on-two-interfaces

** Affects: cloud-init
     Importance: Medium
         Status: New

** Attachment added: "failure on detection"
   https://bugs.launchpad.net/bugs/1996789/+attachment/5631030/+files/GSh4o.png

** Changed in: cloud-init
   Importance: Undecided => Medium

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https://bugs.launchpad.net/bugs/1996789

Title:
  Don't Break On Duplicate Mac Addresses

Status in cloud-init:
  New

Bug description:
  Currently when duplicate mac addresses are detected, cloud-init dies.

  While duplicate macs are typically corner cases, there are cases when
  they can be valid[1].

  Consider this example[2]. After bonding two interfaces, the interfaces
  were left with duplicate mac addresses. Using cloud-init on this
  system fails at the time that these devices are detected.

  If no network config is given, or if a config is given configuring a
  single address, we have the opportunity to do something intelligent to
  allow cloud-init to boot by using the "fallback interface" (in cloud-
  init this is the first interface), rather than throwing an exception
  and dying.

  Netplan's mac matching assumes 1:1 mapping between mac addresses and
  interfaces, so in the case of multiple interfaces configured with
  matches, we still can't do anything intelligent.

  
  [1] Until these have unique addresses, these interfaces will not be usable on the same broadcast domain, but they should still be able to work individually on different networks.
  [2] https://stackoverflow.com/questions/74459180/deleted-bond-interface-left-me-with-duplicate-mac-on-two-interfaces

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