Understanding the Director Group

Director Group Components

When you build a Director group, consider the following elements and concepts.

• Director device—A single management device for the QFabric system. There are two varieties of Director devices: ones that contain a hard drive and ones that do not. Enhanced Director devices with a hard drive provide full processing services, whereas Director devices without a hard drive provide auxiliary support. Therefore, use enhanced Director devices to build the Director group, and supplement the processing power of the Director group by adding Director devices without hard drives to the Director group.
• Director group—A set of Director devices. The Director group is essential to the QFabric system, which cannot operate properly without it. The Director group shares and load-balances processing tasks for the QFabric system, performs topology discovery, assigns identifiers to QFabric system components, and manages interfabric communication. The primary devices in a Director group are enhanced Director devices that contain hard drives. The enhanced Director devices run dual processes in active or standby mode for maximum redundancy.

  When you add additional Director devices to the group, the Director group coordinates their activities and distributes processing loads across all available Director devices. The additional Director devices (either with or without hard drives) provide the Director group with additional memory and processing power. Supplementing the Director group with extra Director devices allows the group to scale efficiently and serve the needs of the entire QFabric system as it grows.

Director Group Services

The Director group is a management platform that establishes, monitors, and maintains all components in the QFabric system. It is a set of Director devices that run the Junos operating system (Junos OS) on top of a CentOS foundation. The Director group handles tasks such as QFabric system network topology discovery, Node and Interconnect device configuration and startup, and Domain Name System (DNS), Dynamic Host Configuration Protocol (DHCP), and Network File System (NFS) services. The Director group also runs the software for management applications, hosts and load-balances internal processes for the QFabric system, maintains configuration and topology databases, and starts additional QFabric system processes as requested.

Another critical role provided by the Director group is the hosting of the virtual Junos Routing Engines. These Routing Engines provide services for the QFabric system to keep it operating smoothly.