Abstract: A host controller migrates live virtual machines from one host to another host to balance the load in the host cluster. In one embodiment, the host controller identifies an overloaded host from the host cluster. The host controller selects a virtual machine from the existing virtual machines that run on the overloaded host based on a percentage value associated with the virtual machine. The percentage value represents CPU usage incurred by the virtual machine on the host. In one embodiment, the selected virtual machine is one that incurs the least amount of load on the host. The host controller then selects a target host from the host cluster as a destination for migrating the selected virtual machine.

Abstract: A method and system for providing up-to-date monitoring results in a virtual machine environment are described. In one embodiment, a control server executes a query pertaining to one or more objects in a virtual machine system, and provides a result of the query to a client for presentation to a user in a graphical user interface (GUI). The control server then periodically re-executes the query to obtain up-to-date information for the objects in the virtual machine system. Upon each re-execution of the query, the control server compares a new result of the query with a previous result of the query to determine whether the up-to-date information for the objects in the virtual machine system has changed. If so, the control server provides the new result of the query to the client. If not, the control server refrains from providing the new result of the query to the client.

Abstract: A host controller selects a host from a host cluster to run a virtual machine. In one embodiment, a host controller receives a request to run a virtual machine. The virtual machine may be a newly added virtual machine, or an existing virtual machine that needs to migrate from a currently active host to another host. The host controller selects a host from the host cluster based on current central processing unit (CPU) consumption and expected load to be incurred by the virtual machine. The expected load may be estimated from the number of cores to be used by the virtual machine. The host controller then assigns the virtual machine to run on the host.

Abstract: Some embodiments of using snapshotting and virtualization to perform tasks in a known and reproducible environment have been presented. A computing device generates a temporary snapshot of a state of a virtual machine. A session of the virtual machine is started on the computing device using the temporary snapshot. The temporary snapshot is automatically destroyed when the session is terminated, wherein any changes made to the state during the session are removed by destroying the temporary snapshot.