Deploy a multi-service application

This topic describes how to use both the MKE web UI and the CLI to deploy a multi-service application for voting on whether you prefer cats or dogs.

To deploy a multi-service application using the MKE web UI:

1. Log in to the MKE web UI.

2. Navigate to Shared Resources > Stacks and click Create Stack.

3. In the Name field, enter voting-app.

4. Under ORCHESTRATOR MODE, select Swarm Services and click Next.

5. In the Add Application File editor, paste the following application definition written in the docker-compose.yml format:

   version: "3"
   services:
   
     # A Redis key-value store to serve as message queue
     redis:
       image: redis:alpine
       ports:
         - "6379"
       networks:
         - frontend
   
     # A PostgreSQL database for persistent storage
     db:
       image: postgres:9.4
       volumes:
         - db-data:/var/lib/postgresql/data
       networks:
         - backend
   
     # Web UI for voting
     vote:
       image: dockersamples/examplevotingapp_vote:before
       ports:
         - 5000:80
       networks:
         - frontend
       depends_on:
         - redis
   
     # Web UI to count voting results
     result:
       image: dockersamples/examplevotingapp_result:before
       ports:
         - 5001:80
       networks:
         - backend
       depends_on:
         - db
   
     # Worker service to read from message queue
     worker:
       image: dockersamples/examplevotingapp_worker
       networks:
         - frontend
         - backend
   
   networks:
     frontend:
     backend:
   
   volumes:
     db-data:
   

6. Click Create to deploy the stack.

7. In the list on the Shared Resources > Stacks page, verify that the application is deployed by looking for voting-app. If the application is in the list, it is deployed.

8. To view the individual application services, click voting-app and navigate to the Services tab.

9. Cast votes by accessing the service on port 5000.

Caution

• MKE does not support referencing external files when using the MKE web UI to deploy applications, and thus does not support the following keywords:

  • build

  • dockerfile

  • env_file

• You must use a version control system to store the stack definition used to deploy the stack, as MKE does not store the stack definition.

To deploy a multi-service application using the MKE CLI:

1. Download and configure the client bundle.

2. Create a file named docker-compose.yml with the following content:

   version: "3"
   services:
   
     # A Redis key-value store to serve as message queue
     redis:
       image: redis:alpine
       ports:
         - "6379"
       networks:
         - frontend
   
     # A PostgreSQL database for persistent storage
     db:
       image: postgres:9.4
       volumes:
         - db-data:/var/lib/postgresql/data
       networks:
         - backend
       environment:
         - POSTGRES_PASSWORD=<password>
   
     # Web UI for voting
     vote:
       image: dockersamples/examplevotingapp_vote:before
       ports:
         - 5000:80
       networks:
         - frontend
       depends_on:
         - redis
   
     # Web UI to count voting results
     result:
       image: dockersamples/examplevotingapp_result:before
       ports:
         - 5001:80
       networks:
         - backend
       depends_on:
         - db
   
     # Worker service to read from message queue
     worker:
       image: dockersamples/examplevotingapp_worker
       networks:
         - frontend
         - backend
   
   networks:
     frontend:
     backend:
   
   volumes:
     db-data:
   

3. Create the application:

   • Built-in Swarm orchestrator
   • Classic Swarm orchestrator

   docker stack deploy --compose-file docker-compose.yml voting-app
     

   docker-compose --file docker-compose.yml --project-name voting-app up -d
     

4. Verify that the application is deployed:

   docker stack ps voting-app
   

5. Cast votes by accessing the service on port 5000.