Primary network swtching between em1 and eth0

[GoForIt]

I'm running F17, and get that the network naming has changed. My issue is that between reboots, my primary ethernet connection gets labeled differently. i.e. One day it shows up as em1, and the next day it's back to eth0. If I reboot a few times, it's back to em1 with not other changes being made. The network connection works through both name changes, but the issue I'm running into is my KVM hosts are set to share em1 (for example), so when the name changes, they lose their network connection.

Running F17, one built in ethernet connection, and one wireless network connection. The wireless names aren't changing between reboots.

[root@dhlt network-scripts]# cat /etc/redhat-release
Fedora release 17 (Beefy Miracle)
[root@dhlt network-scripts]# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.15.100 netmask 255.255.255.0 broadcast 192.168.15.255
inet6 <edited inet 6 addr> prefixlen 64 scopeid 0x20<link>
ether <edited mac addr> txqueuelen 1000 (Ethernet)
RX packets 7331 bytes 6443144 (6.1 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 7148 bytes 1256554 (1.1 MiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING> mtu 16436
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 0 (Local Loopback)
RX packets 3040 bytes 2572978 (2.4 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 3040 bytes 2572978 (2.4 MiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

virbr0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500
inet 192.168.100.1 netmask 255.255.255.248 broadcast 192.168.100.7
ether 52:54:00:ee:f2:95 txqueuelen 0 (Ethernet)
RX packets 393 bytes 30455 (29.7 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 120 bytes 12809 (12.5 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

[root@dhlt network-scripts]# uname -a
Linux foo.local 3.4.0-1.fc17.x86_64 #1 SMP Sun Jun 3 06:35:17 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux

[GoForIt]

Sorry, I realize that I wasn't too clear on what my actual question was. What I'm trying to find out is where I should be looking to get more consistent bahavior. This name switching of the same physical network interface randomly between reboots is causing more and more of a problem for me. If anyone has some ideas about what/where that may be controlled, and how I can get it to be consitent I'd appreciate hearing them. I don't really care if the interface is named eth0, em1, or ob1(kenobie... haha), I just want it not to change on me between reboots.

[DBelton]

I have had that issue as well. On mine, it named the ethernet adapter em1, then a few boots later, it named it em13.

I thought it was just a glitch, but on another machine, it did the same thing. When I installed, the ethernet adapter was named p33p1, and about a month later, it suddenly changed to p33p2.

I have no idea what caused the naming change. I didn't make any network config changes.

[swlib]

To resolve this I have to use the following steps in FC17 release:

- yum install device-mapper* -y
- edit /boot/grub2/grub.cfg and added " biosdevname=0"
- reboot the system

example:

linux /vmlinuz-3.5.0-2.fc17.i686.PAE root=/dev/mapper/vg_lab--248-lv_root ro rd.md=0 rd.dm=0 rd.lvm.lv=vg_lab-248/lv_swap rd.lvm.lv=vg_lab-248/lv_root KEYTABLE=us rd.luks=0 SYSFONT=True LANG=en_US.UTF-8 biosdevname=0 rhgb quiet