On 10/06/14 12:38 PM, Steve Campbell wrote:
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 that I finally switched to a Centos 6 host.
I've not needed more that test VMs, so I've used Virtual Machine Manager 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 that 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:
https://alteeve.ca/w/AN!Cluster_Tutorial_2#Configuring_our_Bridge.2C_Bonds_a...
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.
steve
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 outside: 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?
steve
The bridge is created only on the host. Think of the bridge as being like a virtual switch. When a VM is created, you tell it to connect to the bridge, similar to how you would plug a physical wire into a real switch. That provides the link to the network, and then you configure the virtual server's network just as if it was a real network.
On the host, you don't set the IP on the ethX device, instead you tell ethX to connect to the bridge (look at 'bond2' in the link above for the 'BRIDGE="..."' line). Then you move the host's IP address/config to the bridge itself (look at the 'vbr2' in the link above).
If you're still stuck, tell me the IP addresses you want to set in the host and VM and I'll see if I can bang out a couple sample 'ifcfg-X' files.