#StackBounty: #14.04 #networking #ip #ifconfig Interfaces with non-physical interfaces

Bounty: 100

I found a rather big difference between some boxes I have (some are debian… some ubuntu), and I’m not sure why… or what the fix might be.

Essentially… if I create an “iface” entry in interfaces that doesn’t actually exist with my own configuration to bring the interface up & down… ubuntu complains

user@blah:~# sudo ifup mgmt
Cannot find device "mgmt"
Failed to bring up mgmt.

the interface is defined in ubuntu as such:

iface mgmt inet manual
  up ip netns add mgmt
  up ip link set eth2 netns mgmt
  up ip netns exec mgmt ifconfig eth2 10.0.0.19/24 up
  down ip netns exec mgmt ifconfig eth2 down
  down ip netns exec mgmt ip link set eth2 netns 1
  down ip netns delete mgmt

If I do the same thing on debian… the interface comes up with no issues. The odd thing is that if I don’t have the mgmt interface defined… I get a completely different error:

Ignoring unknown interface mgmt=mgmt.

Running the same thing with the verbose flag… shows ubuntu is trying to bring the interface up before anything else is done. No clue why.


Get this bounty!!!

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