For the exercises in this lab, we will be using Play with Docker. In order to start a session, you need to log in with a Docker Hub account and then press the green “Start” button.

We will also be using the files found in this archive, which contain the definition of the service stack shown in the figure below. The services in the stack are as follows:

• a backend service called backend, with 3 replicas, running on port 5555
• a Postgres database service called db
• a database administration service called adminer, running on port 8080
• a cluster visualisation service called visualizer, running on port 8081.