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Docker Compose: structure and basic usage

This article refers to Platform v3.1.0. The current Platform version is v3.2.0.

Overview​

When you deploy a Docker app to a Barbara edge node, you don't get a terminal on the device to run docker run by hand. Instead, the unit of deployment is a docker-compose.yaml file zipped together with anything else the app needs, uploaded to the App Library. The agent on the node consumes the compose file and runs the containers it describes.

This step walks you through the structure of a docker-compose.yaml, then deploys a simple Filebrowser application both locally and to a Barbara edge node.

Video walkthrough

Watch this step on YouTube: Understanding Docker Compose — Structure and Basic Usage.

Why Docker Compose?​

  • Single-file deployments. Define every service, network, and volume in one YAML file.
  • Reproducibility. Share the same file across environments and get the same stack.
  • Dependencies. Spell out start order and inter-service networking declaratively.
  • Scaling. Modify the replica count of a service without rewriting the deployment.

Structure of docker-compose.yaml​

A typical compose file has four top-level keys.

version​

The Compose schema version.

version: '3.8'

services​

The individual containers that make up the application.

services:
  web:
    image: nginx:latest
    ports:
      - "80:80"

networks​

The networks services connect to.

networks:
  my_network:

volumes​

Persistent storage shared between services.

volumes:
  my_volume:

Practice 1 — run a compose stack locally​

Let's set up a Filebrowser service that exposes a web file manager.

1. Write the compose file​

version: '3.8'
services:
  filebrowser:
    image: filebrowser/filebrowser:latest
    ports:
      - "8080:80"
    volumes:
      - ./data:/srv
    networks:
      - app_network
networks:
  app_network:

2. Start the stack​

docker-compose up -d

3. Verify​

docker ps

Open http://localhost:8080 — you should land on the Filebrowser UI.

4. Tear it down​

docker-compose down

Practice 2 — deploy the same stack to a Barbara edge node​

The Barbara agent expects the compose file zipped inside an application package. Same compose, different distribution channel.

1. Zip the compose file​

Compress the folder that holds the docker-compose.yaml.

2. Create the app in the Library​

  1. Open the Library view in Barbara Panel.
  2. Click New app, name it filebrowser, type Docker, click CREATE.
  3. Open the new application's row, click ADD VERSION, upload your zip, click CREATE.
Upload a new version of the app

Upload a new version of the app

For the full Library reference, see App Library.

3. Deploy to a node​

  1. Open the Node Details page of your edge node.
  2. Click Add card → Application.
  3. Pick filebrowser and follow the deployment wizard.
Filebrowser workload card on the Node Details page

Filebrowser workload card on the Node Details page

4. Access the app​

Open http://<NODE_IP>:8080 in a browser. The Filebrowser UI is now served from the edge node.

Filebrowser app installed on the node

Filebrowser app installed on the node

5. Stop or uninstall​

Use the application's workload card on the Node Details page to stop the app or uninstall it.

Summary​

docker-compose.yaml is the single source of truth for everything Barbara needs to run your app — services, ports, volumes, networks. Knowing how to write one is the prerequisite for every Barbara-specific concept that follows (bind mounts, volumes, networks, secrets, app config, devices, restart policies).