Virtualisation is a way for running multiple servers on same physical hardware. On the servers we run software from VMWare ,one of the leading software for virtulisation.
We are using Dell-Servers with service and support agreement for making sure we always have machines working. We also connect our servers in a redundant supported way.
This way we always have the servers connected to the network. In case of a serious problem we do have backup clusters that can take over and run the services.
All our services are behind multiple internet connections for best possible redundancy.
All our virtual servers are publicly open on internet. It is up to each customer to maintain highest security. Firewall services are available for a cost.