Hipchat Data Center allows you to deploy more Hipchat nodes for greater deployment scale and availability. Hipchat Data Center also externalizes the data stores that were previously included in a single virtual host, allowing greater flexibility for your organization.

A Hipchat Data Center deployment consists of:

• one, or three Hipchat Data Center nodes
  If you choose to deploy three nodes, they must all be of the same software version, and must be located in the same geographic region.

• a load balancer or reverse proxy that handles SSL termination and directs connections to the Hipchat node(s)

  Load balancer vs. Reverse proxy

  Reverse proxy vs. Load balancer

  In both the small- and Enterprise-scale deployment options, clients access the Hipchat node(s) through a service which terminates SSL. This is required regardless of which deployment type you choose. 

  In a small-scale deployment all client connections go to a single Hipchat node, so this service can be a reverse proxy. When you add nodes to create an Enterprise-scale deployment, the service must also function as a load-balancer which distributes client connections among the Hipchat nodes. If you think you might later increase your small-scale deployment to Enterprise-scale, you can choose one of several services (such as NGINX, HAProxy or Apache) that can function as both a load balancer and a reverse proxy.

• a Postgres database, which holds configuration information, preferences and authentication data, integration information, user data, room information, messages, and the audit log
• a Redis server, which stores message read state, the rooms each user has joined, recent messages in rooms and 1:1 chats, and user session information
• a shared NFS file system, which stores attached files shared in messages and rooms, user avatars, and custom emoticons
• optionally, a "jumpbox" or management endpoint inside the cluster

You can learn more about the technical details of these requirements in the deployment options and sizing guidelines, and read more about the configuration requirements for an Enterprise-scale or small-scale Hipchat Data Center cluster.