Administering virtual machines in a distributed computing environment

An apparatus for administering VMs in a distributed computing environment, the distributed computing environment comprising a plurality of hosts, one or more of the hosts executing a virtual machine monitor (‘VMM’), each VMM supporting execution of one or more VMs, the apparatus comprising a computer processor, a computer memory operatively coupled to the computer processor, stored on the computer memory computer program instructions that, when executed by the computer processor, cause the apparatus to carry out the steps of:

• assigning, by a VMM manager, the VMMs of the distributed computing environment to a logical tree topology, wherein assigning the VMMs of the distributed computing environment to a logical tree topology comprises assigning at least two VMMs as a parent-child pair based on network coupling characteristics of a network connection between hosts executing the at least two VMMs;
• and
• executing, in dependence upon an execution policy and responsive to an occurrence of one or more events specified in the execution policy, amongst the VMMs of the tree topology, a broadcast operation, including:
• pausing, by a root VMM of the tree topology, execution of one or more VMs supported by the root VMM;
• sending, by the root VMM, to other VMMs in the tree topology, a message indicating a pending transfer of the paused VMs;
• and
• transferring the paused VMs from the root VMM to the other VMMs, wherein transferring the paused VMs from the root VMM to the other VMMs comprises transferring the paused VMs using multiple data communications messages sent between the VMMs of the tree topology;
• wherein the execution policy specifies one or more actions to take upon the occurrence of the one or more events including duplicating all the one or more VMs of the root VMM on all the other VMMs if a workload executing within the one or more VMs of the root VMM has not completed within particular amount of time.