Do I set up separate bridges for each guest?

Do I set up separate bridges for each guest?

[Neil Aggarwal]

Hello:

I am installing KVM on top of CentOS 5.4 so I can
have two guests running on my host. I would like to 
have the host and guests accessible from my
network.

Do I set up separate bridges for each guest or would
they somehow be shared?

If I set up separate bridges, I think I need to do
in /etc/sysconfig/network-scripts on the host machine:

1. Set up ifcfg-eth0 with the ip information of the 
	host (For example 192.168.2.200)
2. Set up ifcfg-eth0:1 for the first guest.  It will
	have BRIDGE=br1
3. Create ifcfg-br1 with the IP info for the first
	guest (For example 192.168.2.201)
4. Set up ifcfg-eth0:2 for the second guest.  It will
	have BRIDGE=br2
5. Create ifcfg-br2 with the IP info for the second
	guest (For example 192.168.2.202)

Is this correct or did I miss something?

Thanks,
	Neil


--
Neil Aggarwal, (281)846-8957, www.JAMMConsulting.com
Will your e-commerce site go offline if you have
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Re: Do I set up separate bridges for each guest?

[Dor Laor]

On 10/20/2009 04:37 AM, Neil Aggarwal wrote:
> Hello:
>
> I am installing KVM on top of CentOS 5.4 so I can
> have two guests running on my host. I would like to
> have the host and guests accessible from my
> network.
>
> Do I set up separate bridges for each guest or would
> they somehow be shared?
>
> If I set up separate bridges, I think I need to do
> in /etc/sysconfig/network-scripts on the host machine:
>
> 1. Set up ifcfg-eth0 with the ip information of the
> 	host (For example 192.168.2.200)
> 2. Set up ifcfg-eth0:1 for the first guest.  It will
> 	have BRIDGE=br1
> 3. Create ifcfg-br1 with the IP info for the first
> 	guest (For example 192.168.2.201)
> 4. Set up ifcfg-eth0:2 for the second guest.  It will
> 	have BRIDGE=br2
> 5. Create ifcfg-br2 with the IP info for the second
> 	guest (For example 192.168.2.202)
>
> Is this correct or did I miss something?

The simplest thing is to use a single bridge for all -
The physical nic should be part of it and supply the outside world 
connection. The physical nic doesn't need an IP and the bridge should 
own it. All vms can use this bridge.

cat /etc/sysconfig/network-scripts/ifcfg-br0
DEVICE=br0
TYPE=Bridge
ONBOOT=yes
GATEWAYDEV=''
BOOTPROTO=dhcp
DELAY=0
HWADDR=00:14:5E:17:D0:04
# cat /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=none
HWADDR=00:14:5E:17:D0:04
BRIDGE=br0


>
> Thanks,
> 	Neil
>
>
> --
> Neil Aggarwal, (281)846-8957, www.JAMMConsulting.com
> Will your e-commerce site go offline if you have
> a DB server failure, fiber cut, flood, fire, or other disaster?
> If so, ask about our geographically redundant database system.
>
> --
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RE: Do I set up separate bridges for each guest?

[Neil Aggarwal]

Dor:

> The simplest thing is to use a single bridge for all -
> The physical nic should be part of it and supply the outside world 
> connection. The physical nic doesn't need an IP and the bridge should 
> own it. All vms can use this bridge.

I want to assign a static IP to each of the guests,
how would I do that with a single bridge?

Thanks,
	Neil

--
Neil Aggarwal, (281)846-8957, www.JAMMConsulting.com
Will your e-commerce site go offline if you have
a DB server failure, fiber cut, flood, fire, or other disaster?
If so, ask about our geographically redundant database system. 

RE: Do I set up separate bridges for each guest?

[Thomas Besser]

Neil Aggarwal wrote:
> Dor:
>> The simplest thing is to use a single bridge for all -
>> The physical nic should be part of it and supply the outside world
>> connection. The physical nic doesn't need an IP and the bridge should
>> own it. All vms can use this bridge.
> 
> I want to assign a static IP to each of the guests,
> how would I do that with a single bridge?

Whats the problem? Define the static IP in your guests and it should work.

Regards
Thomas