Continuous Delivery with Docker and Jenkins

Scaling services

Docker Compose provides the functionality to automatically create multiple instances of the same container. We can either specify the replicas: <number> parameter inside docker-compose.yml or use the docker-compose scale command.

As an example, let's run the environment again and replicate the calculator container:

$ docker-compose up -d$ docker-compose scale calculator=5

We can check which containers are running:

$ docker-compose ps Name                     Command             State Ports ---------------------------------------------------------------------------calculator_calculator_1   java -jar app.jar   Up   0.0.0.0:32777->8080/tcpcalculator_calculator_2   java -jar app.jar   Up   0.0.0.0:32778->8080/tcpcalculator_calculator_3 java -jar app.jar Up 0.0.0.0:32779->8080/tcp ...