The main areas that have been stabilized during this cycle are:

• Sunstone interface, that fixes most of the bugs reported since the Beta release and cleans some aspects of the UI. You should expect a more stable look & feel. There is a couple of minor issues that will be solved for the final release. We've put some effort in scaling the deployment of the web application (i.e. to rack Sunstone in multiple processes or hosts).

• Sunstone views. This is a new feature that allows you to customize the UI for different users or user groups, so the interface implements the provisioning model for each role. Sunstone views replaces the 3.x self-service portal. Sunstone views does not require any additional service (apart from the sunstone server). Sunstone ships with two predefined views admin and user, we may add a couple of more pre-defined views for the final release.

• Better VM operations. Now you can undeploy a running VM keeping the instance defined (holding any resource, IP or image) but without consuming any host capacity. The action names are now stable and in their final form. Note that we have change back vm destroy to vm delete to keep the compatibility and coherence with the other resources.

• Packaging. We've solved multiple issues in the binary packages.

The complete list of new features of OpenNebula 4.0 can be checked in the Beta release notes, and the incremental list of changes and bug fixes from 4.0 Beta are shown here.

Although this release is considered stable, we are still fixing some bugs and it is aimed at testers and developers to try the new features. Your feedback is more than welcomed for the final release.

There are no special upgrade or compatibility issue if you are running 4.0 beta. Just upgrade the database version with the onedb upgrade command. You may be interested in configuring your views.

There have been minor changes in the OpenNebula DB schema to accomodate the new features in 4.0. These changes are automatically managed by the migration process, but if you have developed any customization 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 3.x installation please refer to the Compatibility Guide. You should also read this document if you are an OpenNebula 3.x user.

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

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

The documentation of OpenNebula 4.0 can be found here.

Find here the list of known issues in the RC, to be corrected for the final release.

vmfs drivers are known to be broken, please wait for the final release for them to be fixed

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.

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.