Lab
A Cloud Guru

Building a Docker Application Stack

Stacks are one of the most powerful orchestration features available in Docker Swarm. They allow you to easily manage complex applications consisting of multiple interdependent components running in separate containers. In this lab, you will have the opportunity to work with Docker stacks by building a multi-component application as a Docker stack. You will also learn how to manage existing stacks by scaling a stack's services after it has already been deployed. This will give you some hands-on insight into Docker stacks.

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Path Info

Level

Intermediate

Duration

1h 0m

Published

Jun 06, 2019

Challenge

Build and deploy the application stack.
1. Create an empty project directory with a Docker compose YAML file inside.
```
cd ~/
mkdir produce
cd produce
vi produce.yml
```
1. Build a stack definition in produce.yml to meet the provided specifications.
```
version: '3'
services:
   fruit:
     image: linuxacademycontent/fruit-service:1.0.1
   vegetables:
     image: linuxacademycontent/vegetable-service:1.0.0
   all_products:
     image: linuxacademycontent/all-products:1.0.0
     ports:
     - "8080:80"
     environment:
     - FRUIT_HOST=fruit
     - FRUIT_PORT=80
     - VEGETABLE_HOST=vegetables
     - VEGETABLE_PORT=80
```
1. Deploy the stack using the compose file.
```
docker stack deploy -c produce.yml produce
```
1. Verify that the stack is working.
```
curl localhost:8080
```
Note that after deploying, it may take a few moments for the stack to become responsive. You can check the status of the services with docker stack services produce. Once the services are up and running, you should get some JSON data containing a combined list of fruits and vegetables.

Challenge

Scale the Fruit and Vegetable services in the stack.

Set the number of replicas to 3 for the Fruit and Vegetable services in the compose file.

vi produce.yml

version: '3'
services:
   fruit:
     image: linuxacademycontent/fruit-service:1.0.1
     deploy:
       replicas: 3
   vegetables:
     image: linuxacademycontent/vegetable-service:1.0.0
     deploy:
       replicas: 3
   all_products:
     image: linuxacademycontent/all-products:1.0.0
     ports:
     - "8080:80"
     environment:
     - FRUIT_HOST=fruit
     - FRUIT_PORT=80
     - VEGETABLE_HOST=vegetables
     - VEGETABLE_PORT=80

Redeploy the stack using the compose file.

docker stack deploy -c produce.yml produce

Verify that the stack is still working.

curl localhost:8080

You should get some JSON data containing a combined list of fruits and vegetables.

Use docker stack services produce to see that the number of replicas for the Fruit and Vegetable services is now 3.

Author

A Cloud Guru

The Cloud Content team comprises subject matter experts hyper focused on services offered by the leading cloud vendors (AWS, GCP, and Azure), as well as cloud-related technologies such as Linux and DevOps. The team is thrilled to share their knowledge to help you build modern tech solutions from the ground up, secure and optimize your environments, and so much more!

What's a lab?

Hands-on Labs are real environments created by industry experts to help you learn. These environments help you gain knowledge and experience, practice without compromising your system, test without risk, destroy without fear, and let you learn from your mistakes. Hands-on Labs: practice your skills before delivering in the real world.