The OpenNebula Team is releasing a new plug-in to interface the ElasticHosts cloud provider, so it can be used to dynamically increase capacity of your virtualized infrastructure to meet fluctuating or peak demands. This can happen when the local fabric runs out of capacity to spawn a new virtual machine, therefore it may be interesting to add capacity using cloud providers.
ElasticHosts offers KVM based virtualized hosts in a cloud like fashion, i.e., à la Amazon EC2, using a very neat RESTful API. Uploading images (drives, in ElasticHosts speak) previously configured with the service that needs to meet a increased demand would allow the cloudbursting described above through OpenNebula.
Information on how to download and install the ElasticHosts plug-in can be found in the OpenNebula Trac.