Internal/Isolated networks on oVirt

For those who are accustomed with virt-manager administration and operation, create an isolated network among the VMs seems to be a very easy task. But oVirt haven’t so direct configuration. In fact, we need some commands on terminal. I must tell you this post is valid only when you have just one host hypervisior. With 2 or more, external connectivity is inevitable.

In order to create an internal network you can use dummy module. First of all, make sure your server loads dummy module at startup.
Create /etc/sysconfig/modules/dummy.modules:

modprobe dummy > /dev/null 2&1
exit 0

Manually, you can run modprobe to load in runtime. It will appear a dummy0 network interface. Done this, create /etc/sysconfig/network-scripts/ifcfg-dummy0 with this content:

DEVICE=dummy0
BOOTPROTO=none
ONBOOT=yes
NM_CONTROLLED=no
PROMISC=yes

Now comes the oVirt configuration. In webadmin portal, go to the ‘Network’ tab and click new:

New network
New network

The definition could be simple. Just give a name and match ‘VM network‘:

New network
New network

With the virtual switch created, we need to link our dummy interface on it. Go to the network configuration of host:

Configure network on host
Configure network on host
Configure network on host
Configure network on host

Drag internal network and drop in dummy0 interface

Configure network on host
Configure network on host

Check ‘Save network configuration’ and click OK.

Configure network on host
Configure network on host

Now, for each virtual machine you want to use internal network, you can create a virtual NIC and attach to internal virtual switch.

Configure network on guest
Configure network on guest

It was tested on oVirt 3.4 setup in all-in-one mode.