eth0 not being configured automatically

Question

When I start an ubuntu 12.10 instance, eth0 is NOT getting configured.

davidparks21@MySqlDB:~$ cat /run/network/ifstate
lo=lo

When I manually edit ifstate and add eth0=eth0 and service restart networking then eth0 gets configured properly and we're all happy.

Reboot though, and I loose the configuration and have to manually edit ifstate and add it again and restart networking.

What configuration might I be missing here?

---

root@prodweb1:~# cat /etc/network/interfaces

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto eth0
iface eth0 inet static
 address 10.1.3.10
 netmask 255.255.0.0
 broadcast 10.1.255.255
 gateway 10.1.0.1
 dns-nameservers 8.8.8.8
 dns-nameservers 8.8.4.4

Solution

To start your eth0 at reboot you need to add an entry in /etc/network/interfaces like below for eth0.

auto eth0
iface eth0 inet dhcp

Comments

[Admin]

help.ubuntu.com/10.04/serverguide/…

[Admin]

Does ifup -a brings the interface up?

[Admin]

What's the output of ip a s eth0?

[alok chauve]

I should have mentioned that I have auto eth0 iface eth0 inet static and all of the parameters configured. They take effect when I add eth0=eth0 to /run/network/ifstate correctly. But reboot and it doesn't configure eth0 properly.

[alok chauve]

The only "error" I see in dmesg is [20277.511852] type=1400 audit(1365069410.434:54): apparmor="DENIED" operation="mount" info="failed flags match" error=-13 parent=18836 profile="lxc-container-default" name="/" pid=18847 comm="mount" flags="ro, remount", because this is an LXC container and mounts aren't allowed, but this doesn't seem related.

[alok chauve]

I also see this [ 13.985304] igb: em1 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: RX, perhaps it has something to do with me renaming em1 on the host to eth0 on the LXC container.

[Pablo Saratxaga]

after googling a bit it seems the em# names are the new kernel naming for motherboard embedded ethernet cards. And there is a kernel boot option to disable that behaviour; so try adding biosdevname=0 to the kernel booting options. alternatively, you could try configuring "em1" instead of "eth0" in /etc/network/interfaces file.