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.
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:
The definition could be simple. Just give a name and match ‘VM network‘:
With the virtual switch created, we need to link our dummy interface on it. Go to the network configuration of host:
Drag internal network and drop in dummy0 interface
Check ‘Save network configuration’ and click OK.
Now, for each virtual machine you want to use internal network, you can create a virtual NIC and attach to internal virtual switch.
It was tested on oVirt 3.4 setup in all-in-one mode.