[CentOS-virt] Finally switching from Xen to KVM - question about networking
campbell at cnpapers.com
Tue Jun 10 16:38:49 UTC 2014
On 6/10/2014 12:05 PM, Digimer wrote:
> On 10/06/14 11:46 AM, Steve Campbell wrote:
>> On 6/10/2014 10:46 AM, Digimer wrote:
>>> On 10/06/14 10:03 AM, Steve Campbell wrote:
>>>> I had so much trouble putting Centos 6 guest VMs on a Centos 5 host
>>>> I finally switched to a Centos 6 host.
>>>> I've not needed more that test VMs, so I've used Virtual Machine
>>>> on the old system, which worked pretty well, so I decided to create my
>>>> first KVM guest machine. I noticed when I created it, I only had the
>>>> options of NAT for my network interface, so I used that (obvious).
>>>> Well, after starting the VM, I find I don't have connectivity with
>>>> interface. Reading, I find examples where I need to create bridges
>>>> perhaps. Xen did most of this for me, so it's a little new to me.
>>>> Can anyone throw me a clue, please?
>>>> steve campbell
>>> Setting up a bridge is not that hard, and it will give your VMs direct
>>> access to the outside world, and host <-> VM access just fine as well.
>>> Here is a link showing how to setup a bridge connected to a bond
>>> device. Ignore the bond and pretend it is a straight ethX device:
>> The host has a device named virbr0 that is installed during system
>> installation. It also has a network device vnet0. There are no files in
>> /etc/sysconfig/network-scripts for these.
>> Shouldn't I be able to use the virbr0 virtual bridge for this? I've
>> tried setting up the VM's device with all of the options that is listed,
>> but to no avail.
>> Should I need to set up another bridge for this?
>> And thanks for the link.
> virbr0 is created and managed by libvirtd. If you open Virtual Machine
> Manager, connect to localhost and then double-click on 'localhost',
> you will see a tab for creating/managing bridges (NAT'ed, generally).
> I disable 'virbr0' as NAT'ing is generally not what I want.
> The 'vnetX' devices are dynamically created to link a VM's interface
> to a bridge. Think of them as virtual network cables. They get created
> and destroyed as needed.
Sorry, but I'm confused:
My host server has a real NIC and IP address with a real gateway to the
virtbr0 IP: 192.168.122.1
Host IP: 10.0.5.16
Gateway IP: 10.0.5.1
on eth0 and this works
My VM server has all fake stuff currently:
Host IP: 10.0.5.17
Gateway IP: 10.0.5.1
on eth0 and this is like NIC without a cable.
So I need to create a bridge device on both the host and VM (lets say I
name it br1). I change the eth0 config file on both host and VM to point
to br1 and give the br1 config file on both host and VM the correct IP.
But won't this just let the two talk to each other. How will the VM
server get outside?
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