Docker Compose DNS Load Balancing Example

This is to demonstrate the Docker Compose scale command and how it can be used with Nginx for instant scaling.

Building

Requirements

• Go
• Docker Compose
• GNU Make

To build, first compile the Go web application server. This will simply respond with the container's ID.

$ make

Running

$ docker-compose up -d

Then browse to http://localhost and see the name of the single application container.

Scaling

To scale the application server, run

$ docker-compose scale application=2

(or any number of instances). Then refresh the browser to see the container name change as Docker's DNS resolver does round-robin.