lbalancer

A simple load balancer application written in go.

To build it

go build

To run it

./lbalancer -config=/path/to/config.yaml

A sample config.yaml file can be like this:

port: 12345
type: random
health-check-interval: 5
backends:
  - url: http://localhost:9091
    weight: 10
  - url: http://localhost:9092
    weight: 20
  - url: http://localhost:9093
    weight: 30

Here, health-check-interval field denotes a time interval in second which should be a positive value. After each health-check-interval seconds, the load balancer will periodically check the health of the backends and update their status. If the field health-check-interval is missing or set to 0 then it will be set to a default value which is 10 seconds. If the field is set to a negative value, then health checking will be disabled.

Currently 4 types of load balancing methods are supported which can be mentioned in yaml file through type field:

1. Round robin: requests are forwarded to servers evenly. This one is the default type.

type: round-robin
backends:
  - url: http://localhost:9091
  - url: http://localhost:9092

2. Weighted round robin: requests are forwarded to servers based on the mentioned weight in the yaml file. If no weight is mentioned for some backend, the default weight will be 1.

type: round-robin
backends:
  - url: http://localhost:9091
    weight: 10
  - url: http://localhost:9092
    weight: 20

3. Least connections: requests are forwarded to server with least connection considering weight of the servers.

type: least-conn
backends:
  - url: http://localhost:9091
    weight: 10
  - url: http://localhost:9092
    weight: 20

4. Random: requests are forwarded to server randomly considering weight of the servers.

type: random
backends:
  - url: http://localhost:9091
    weight: 10
  - url: http://localhost:9092
    weight: 20