Abiquo 4.5 introduces new configuration properties to control the number of concurrent operations for a hypervisor or provider, device, or backup manager. The platform can control concurrency for VM operations and many kinds of entities associated with VMs (firewalls, load balancers, NAT IPs, and backups).
You can now define limits for specific hypervisor type or provider (e.g. vCloud with no concurrency) without affecting other types (e.g. ESXi with maximum concurrency). And you can also change the context of concurrency control to the VDC level. This means that the platform can apply any of the limits PER VDC. This means you can limit concurrent operations that affect the same virtual datacenter, while allowing concurrent operations to other VDCs. This is helpful because vCloud Director does not support concurrent operations to vApps, which are Abiquo VDCs.
You can also allow concurrent operations that change the state of a VM (e.g. power on), while limiting concurrent configure operations.