Fixing strange device names using Ubuntu templates on VMware ESX or vSphere

If you regularly deploy Ubuntu VM templates on your VMware ESX(i) or VMware vSphere boxes you will probably run into strange network device numbers. This is caused by a udev rule. This problem has been confirmed to exist in Ubuntu 9.04, 9.10 and 10.04. I haven’t had the time to check out other versions of Ubuntu. It’s also still existing in RHEL 6 and Scientific Linux 6.

As you can see below we have two ethernet devices: eth4 and eth5 instead of the usual eth0
and eth1.

root@box:~# ifconfig | grep Link
lo        Link encap:Local Loopback  
eth4  Link encap:UNSPEC  HWaddr  
eth5  Link encap:UNSPEC  HWaddr  
root@box:~#

Lucky for us it’s very simple to persistenly assign the correct device names to the corresponding mac address.

root@box:~# grep eth4 /etc/udev/rules.d/70-persistent-net.rules 
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", 
ATTR{address}=="00:11:22:33:44:55", ATTR{dev_id}=="0x0", 
ATTR{type}=="1", KERNEL=="eth*", NAME="eth4"
root@box:~#

Use your favorite editor to edit /etc/udev/rules.d/70-persistent-net.rules.
Replace NAME=”eth4″ with NAME=”eth0″ and do the same with eth5.
Save the config file, reboot and you’re done!

Update:
After writing this guide I’ve also found this issue to exist on other udev-based distro’s (e.g. OpenSUSE) and other VMware products too (e.g. Fusion and Workstation). The same fix applies, so no worries there.