Running Docker Compose

Starting Containers (up)

docker compose -f mongodb.yaml up -d

Explanation

• -f specifies the file name
• up means create and start all containers defined in the file
• -d runs everything in detached mode (in background)

What Happens When We Run This?

1. Creates a default network automatically
   (example name: test-app-default)
2. Creates all services defined in the YAML file
3. Starts all containers
4. Connects all containers to the same network

Example Containers Started

• mongo
• mongo-express

• Start MongoDB container
• Start Mongo Express container
• Connect both internally using the default network

Important Note

the version attribute is obsolete

• Ignore it, OR
• Remove the version field from the YAML file

Stopping and Removing Containers (down)

docker compose -f mongodb.yaml down

What Happens When We Run This?

1. Stops all running containers defined in the file
2. Removes those containers
3. Removes the automatically created network
4. Cleans up the entire Compose setup

Before vs After

Key Takeaways

• docker compose up -d → Starts the full application stack
• docker compose down → Completely removes the stack
• Docker Compose automatically handles:
  • Networks
  • Container creation
  • Container startup
• One file manages the entire multi-container setup