ALB Basic Principles

Overview

Access Load Balance (ALB) allows external systems to access clusters through HTTP or sockets. After requests are received, ALB forwards them to BLUs in the cluster for conversion between interfaces of different protocols. BLUs are developed based on the service consumer specifications and provide RESTful APIs for external systems.

In FusionInsight RTD, ALB is not provided as an independent service but integrated with Containers.

Structure

Figure 1 ALB structure

• ALB is used between service consumers and service providers.
• ALB provides access channels for untrusted networks, shields internal topology details, and implements internal load balancing and service routing.

Principles

ALB provides multi-protocol access, which improves the networking adaptability of FusionInsight RTD. In a complex network where the FusionInsight RTD client and cluster are not in the same network segment, ALB can be used as the gateway to process messages, distribute requests to service instances, and control distribution policies.

After FusionInsight RTD is installed, the system administrator can deploy ALB on the platform. Physically, ALB is a preset BLU in FusionInsight RTD.

Relationship with Other Components

• ALB and BLU

  ALB is a load balancer that hides BLU's multiple instances. Customers can use ALB to access BLUs.

• ALB and ZooKeeper

  ZooKeeper provides the service registration center. ALB subscribes to services from the registration center as a service consumer.