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romu
Asked: 2014-01-07 07:22:29 +0800 CST

My KVM machine can't get the network

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I'm setting up a virtualization server for my company based on Fedora 19 and KVM. Our goal is to being able to convert and run a bunch of VirtualBox VMs.

So I setup my F19 server, and created a br0 network bridge with bridge-utils. I first tried with VirtualBox, and no trouble, my testing VM (Ubuntu Server 10.04) works as it did on Windows.

Then, I converted the VM to qcow format and added this new VM to Virt-Manager. I can start it, log in, etc, everything works...except the network.

  • ifconfig returns only the "lo" loopback adapter
  • lspci shows well the "Ethernet Controller" of the correct type as specified in Virt-Manager

I've tried to change from bridge to NAT, change the type of network adapter in Virt-Manager, nothing works.

Any idea how to fix this?

networking

2 Answers

  1. You need to look in the VM itself, probably regenerate the network configuration.

    The MAC address of the NIC changed when you switched to KVM and the network driver is also different, so you need to configure your new NIC in the VM instead of expecting it to just appear.

    Start with checking the udev persistent-net rule file, it might still hold a record for the old NIC, which needs to be removed, and then run udevadm trigger to regenerate the file. At this point a new, correct network config should already be in place of course.

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  2. Thanks to @NathanC, I've found the issue. The adapter provided by KVM is labeled as Eth2 instead of the original network link Eth0. So I just had to replace eth0 by eth2 in the /etc/network/interfaces and now it works. Perfect!

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