Ethernet interface name stuck to br0 or renaming ethernet interfaces
If while configuring bridge as explained in Creating bride interfaces (br0) for virtual hosts to use shared interface base machines ethernet interface name starts getting stuck to br0/br1 etc. instead of eth0/eth1. Then the problem is in ifcfg-br0 file where HWADDR=<MAC address of ethernet interface> has been left by accident. To solve this problem simple changes to ifcfg-files may not be enough as the configuration lines make their way to '/etc/udev/rules.d/70-persistent-net.rules'. Hence first one would have to remove HWADDR line from ifcfg-br0, add it properly to ifcfg-eth0 and then remove incorrect lines from '/etc/udev/rules.d/70-persistent-net.rules'. Then as suggested in Xen troubleshooting it could be worth it to poweroff the machine for about 30 seconds instead of just rebooting it.
Note that for Ethernet interfaces named __tmpXXXXX there is separate note at Ethernet devices named __tmpXXXXX