vCloud Director Scaling

vCloud Director multicell environment:
HTTPS load balancer in front of cells   All cells share vCloud Director database.   vCloud Director cells scale horizontally.   NFS server for vSphere vApp file transfer service
Recommendation: • All cells are on a single site. • All infrastructure local to site.

Multiple cells require load balancing to manage heavy use of Web and remote consoles. Options include configuring round-robin DNS or using a third-party load-balancing product.
A single cell can support many vCenter Server instances. These instances should all be in the same site to avoid potential latency. You must also scale your vSphere deployment to provide the resources necessary for the multiple vCloud Director cells.
vCloud Director cells are stateless front-end processors for vCloud. All cells connect to a central database. Each cell has a variety of purposes and self-manages various functions among cells. The cell manages connectivity to the cloud and provides both API and UI endpoints or clients.

Multiple cells (a load-balanced group) should be used to address availability and scale. This addressing is typically achieved by load balancing or content switching the front-end layer. Load balancers present a consistent address for services, regardless of the underlying node responding. Load balances can spread session load across cells, monitor cell health, and add or remove cells from the active service pool.
If your vCloud Director installation includes multiple cloud cells running behind a load balancer or a network address translation (NAT) device, or if the cloud cells do not have publicly-routable IP addresses, you can set a public console proxy address. During the initial configuration of each cloud cell a remote console proxy IP address is specified. By default, vCloud Director uses that address when a user attempts to view a virtual machine console. To use a different address, specify a public console proxy address.

In general, any load balancer that supports SSL session persistence and has network connectivity to the public-facing Internet or internal service network can perform load balancing of vCloud Director cells. General concerns around performance, security, manageability, and so on should be taken into account when deciding to share or dedicate load balancing resources.