What's the best way to have a 169.254.169.254 address local to my laptop?

Question

I want to emulate the Amazon EC2 metadata service on my local system for testing. In EC2, this runs on 169.254.169.254. I understand that this is the designated range for pseudorandom local addresses on DHCP failure, but Amazon in their wisdom are also using it for this purpose, so I need to do the same thing.

I'm using F19 Alpha. In earlier Fedora, I could simply make a virtual interface on the loopback device, like lo:0 and assign that a static address using the normal ifcfg- scripts. Now, that fails with "Error: Connection activation failed: Device not managed by NetworkManager or unavailable".

(I'm running NetworkManager, but previously I was doing this underneath it.)

Is finding some way to continue what I was doing with lo:0 the right approach (and if so, how?), or is there a better way?

Answer 1

To answer your specific question, you can use iproute2 to assign the IP address like this:

sudo ip addr add 169.254.169.254/8 dev lo

It will just add a new IP to the interface, no need for aliasing with :0, :1, etc. Note this is going to be lost after a reboot.

And to quickly emulate the metadata service you can use netcat like this:

while true; do sudo nc -l 169.254.169.254 80 <<< '"region" : "eu-west-1"'; test $? != 0 && break; done

This will give you the region when asking like this:

curl -s http://169.254.169.254/latest/dynamic/instance-identity/document

Answer 2

Haven't used Fedora in a while, but it should still be very similar to CentOS. I did this on CentOS 6.

Copy /etc/sysconfig/network-scripts/ifcfg-lo to /etc/sysconfig/network-scripts/ifcfg-lo:1

Your new config should look like so:

DEVICE=lo:1
IPADDR=169.254.169.254
NETMASK=255.0.0.0
ONBOOT=yes
NAME=loopback1

Restart the network service service network restart.

Bonne chance mon ami !