In the following list you can check the highlights of OpenNebula Flame organised by component (a detailed list of changes can be found here):

• Datastore Monitoring, the capacity of the datastores is now monitored by the drivers. This will help users and admins to quickly identify the resource usage of the cloud. Admins can also set security threshold in capacity usage.
• New Hooks, you can now program hooks on any transition. Also the information of the previous state can be passed as a hook argument to customized the action depending on the original VM state. Read more about this here.

• VMware, the whole set of VMware drivers, storage, networking and virtualization has been greatly improved. The storage system has been simplified and made more efficient, see more here. This change was made to favour the most demanded and useful combination, in order to focus efforts and stabilize it. The networking drivers have been also streamlined. Monitoring of ESXi hosts is now complete and the functionality of the virtualization drivers is now levelled with KVM and Xen. In the process the runtime dependencies of VMware has been reduced by accessing the native VMware VI API.

• Xen, support for the Xen4 interfaces through the xl command. Xen3 is totally supported with its own set of drivers. More on this in the Xen guide.

OpenNebula Gate (onegate) is the VM gate to OpenNebula.

• With a security token the VMs can call back home and report guest and/or application status in a simple way, that can be easily queried through OpenNebula interfaces (Sunstone, CLI or API).
• OpenNebula Gate metrics can be also used in conjuntion with OneFlow to develop advanced auto-scaling policies. More information about OpenNebula Gate here.

Sunstone has been polished since its redesign in 4.0:

• Improved VNC, you can now detach VNC sessions from the Sunstone tab. This let you use the whole window area, prevents synchronisation problems with mouse pointers, and… yes! ESC key now works!
• VM definition update, the template dialog is also used to update your VM definitions without the need to go to the text based view.
• Performance improvements, internal improvements in the information management and resource access.
• Self-service view, we have a created a “cloudy” provisioning scheme for users, see more on this here.

This release is the first one to include the OpenNebula OneFlow component (former AppFlow component available in OpenNebulaApps). OneFlow allows users and administrators to define, execute and manage multi-tiered applications, or services composed of interconnected Virtual Machines with deployment dependencies between them. This version also comes with handy new features:

• Auto-scaling policies: A service is composed by roles, each one corresponding to one VM template and each one with certain cardinality, ie, the number of instances of the same VM template. A role's cardinality can be adjusted manually, based on metrics, or based on a schedule. Read more here
• Service management has been greatly improved, with the ability to recover from fault situations, the ability to apply operations to all the VMs belonging to certain role, the ability to define a cooldown period after a scaling operations, … and many other useful features
• Apply scheduling actions to the VMs that conforms a role.
• Updated sunstone interface

There have been minor changes in the OpenNebula DB schema to support the new datastore monitor subsystem. These changes are automatically managed by the migration process, but if you have developed any customisation you may need to update it.

A detailed upgrade process can be found in the documentation. For a complete set of changes to migrate from a 4.0 installation please refer to the Compatibility Guide.

OpenNebula is released under the Apache 2.0 open source license. The complete source tree and binary packages for OpenNebula can be downloaded here.

Packages for the beta are available for various distros: Ubuntu LTS and latest, CentOS, OpenSUSE and Debian.

Please report any bug or send feedback at the development portal or at the mailing list.

The documentation of OpenNebula 4.2 can be found here.

The OpenNebula project would like to thank the community members and users who have contributed to this software release by being active with the discussions, answering user questions, or providing patches for bugfixes, features and documentation.

The new features for service elasticity (oneFlow) introduced in OpenNebula 4.2 were funded by BlackBerry in the context of the Fund a Feature Program.

More information about the project can be found at the project web page. You may be also interested in checking the OpenNebula Ecosystem that includes many interesting projects contributed by the community to enhance or add new features to OpenNebula.