Hello,

I have servers that have swappable hard drives and two NICs.
When I moved one to another server, the network would no longer work stating that the device eth0 was no longer present. Instead, i had eth2, eth3.

I did some research and found that if you delete /etc/udev/rules.d/70-persistent-net.rules it would work again. So, i deleted that file and it did find eth0 and eth1 again... but then all my IP settings i had set up in my sysconfig files no longer worked. Then, when i switched the network cable to the other NIC it all worked. For some reason it did not map eth0 to the same port (same location on back of server) on the new machine.

How can I insure that eth0 always be mapped to the port I want it to be on? Is it even possible with udev? Or anything else I can do?

Thank you.

Are your servers that you swap drives between all based on identical hardware?

Possibly it would allow you to edit the persistent rules file and make the appropriate card with the specific MAC address eth0..
so you would end up with 2 rules that map to eth0 but one rule would be for each server ..

I don't know if that is allowed (two rules mapping to the same device name) but you could certainly try it.. I'm thinking it might ignore the rule for the device that doesn't exist..

An alternative is to ignore the MAC address completely in the name assignment rules and use the PCI bus location. With identical hardware (ie motherboards with multiple network interfaces) the PCI bus location will be the same.

For example:
SUBSYSTEM=="net", SUBSYSTEMS="pci", ACTION=="add", DRIVERS=="?*", KERNELS=="0000:04:02.0", NAME="eth0"
SUBSYSTEM=="net", SUBSYSTEMS="pci", ACTION=="add", DRIVERS=="?*", KERNELS=="0000:04:02.1", NAME="eth1"