• The vCloud Availability Portal is a virtual appliance that provides a graphical user interface for tenants to facilitate the management of vCloud Availability for vCloud Director operations

• Existing vCloud Director cells are extended with Cloud Proxies. These use the same Red Hat Enterprise Linux / CentOS guest OS and vCloud Director binaries as the cells, but have most of the vCloud services disabled. They still need to have access to the vCloud database as well as to the NFS transfer share. They can be load balanced with different public virtual IP addresses (VIPs) and have different SSL certificates than the vCloud cells. Deployment of Cloud Proxies scales out with the number of concurrent tunnels.

• RabbitMQ is used for vCloud API extension to provide communication between vCloud Director cells and vSphere Replication Cloud Service. For high availability, RabbitMQ usually consists of at least two clustered nodes with mirrored queues. The nodes must be behind a load balancer and presented under one virtual IP address.

• Cassandra noSQL database cluster is used for vSphere Replication Cloud Service replication metadata and configuration storage. For high availability, at least three nodes must be deployed to provide quorum consistency level, with replication factor 3. A network load balancer is not required to access the Cassandra database because vSphere Replication Cloud Service automatically chooses an available node to communicate with. The node discovery is performed through the Platform Services Controller lookup service where each Cassandra node is registered.

• vSphere Replication Cloud Service is a virtual appliance that provides the management functionality and APIs for vCloud Availability for vCloud Director. For high availability, at least two appliances must be deployed without a need for a network load balancer. The appliances use a common Cassandra database and communicate with vCloud Director through the RabbitMQ message bus. The appliances discover other service components through Platform Services Controller lookup service.

• VMware Platform Service Controller runs the lookup service that is required for discovery of vCloud Availability for vCloud Director components (Cassandra nodes, vSphere Replication Manager Server, vSphere Replication Cloud Service), and provides secure token service to authenticate replication solution users to vCloud Director. For high availability, an external Platform Services Controller is required and can be deployed in form of VMware vCenter Server Appliance with all but Platform Services Controller services disabled or as Windows installable. This Platform Services Controller can be separate from Platform Services Controller instances used by Resource Group vCenter Server instances but must be within the same vSphere domain. While a two-node load balanced Platform Services Controller set up in a single site is recommended, a single node Platform Services Controller protected with VMware vSphere High Availability might be sufficient, depending on required availability SLAs.

• vCloud Availability for vCloud Director Installer is a virtual appliance that simplifies the deployment, configuration, and management of all vCloud Availability for vCloud Director components.