Components of a load balancer
At it's most basic, load balancing is made up of three components:
- Pools: Which contain one or more endpoints.
- Endpoints: Which respond to individual requests.
- A load balancer: Which decides which traffic goes to each pool.
Normally, requests to your application would go to individual servers directly.
With a load balancer, requests first go through the load balancer. Your load balancer then routes requests to specific pools.
flowchart LR
accTitle: Load balancing flow
accDescr: Load balancing involves a load balancer, pools, endpoints, monitors, and health monitors.
B[Request 1] --> A
C[Request 2] --> A
D[Request 3] --> A
A[Load balancer] -- Request 1 --> P1
A -- Request 2 --> P2
A -- Request 3 --> P3
subgraph P1 [Pool 1]
Endpoint1((Endpoint 1))
Endpoint2((Endpoint 2))
end
subgraph P2 [Pool 2]
Endpoint3((Endpoint 3))
Endpoint4((Endpoint 4))
end
subgraph P3 [Pool 3]
Endpoint5((Endpoint 5))
Endpoint6((Endpoint 6))
end
Within each pool, requests then go to individual endpoints. And that endpoint is what responds to the request.
flowchart LR
accTitle: Pool traffic flow
accDescr: When an incoming request reaches a pool, it then goes to an endpoint within the pool.
A[Request 1] --Routed by pool--> Endpoint2
subgraph P1 [Pool]
Endpoint1((Endpoint 1))
Endpoint2((Endpoint 2))
end
This progression of load balancer --> pool --> endpoint is the core part of how a load balancer works.