docker service. make it not start at docker compose up.

Disabling the automatic start of a service in Docker Compose during the docker-compose up command can be crucial for various development scenarios, especially when you may want to control the specific services running at any given time. Below are detailed methods and strategies to achieve this.

Understanding Docker Compose Service Management

When you run docker-compose up, all services defined in your docker-compose.yml file are started by default. However, you may want to prevent certain services from starting automatically for reasons such as debugging, resource management, or selective development.

Options to Prevent Automatic Startup

1. Remove the Service from docker-compose.yml Temporarily

One of the simplest approaches is to comment out or temporarily remove the service from your docker-compose.yml file. For instance:

version: '3'
services:
  web:
    image: nginx
  # db:
  #   image: postgres

This way, when you run docker-compose up, the db service won’t start since it is not defined in your configuration.

2. Using Docker Compose Profiles (V2.1 and Later)

Docker Compose introduced profiles to manage services better. You can define which services to include while running the command. Here’s how you can set this up:

version: '3.9'
services:
  web:
    image: nginx
    profiles:
      - frontend

  db:
    image: postgres
    profiles:
      - backend

You can start the web service without the db service by running:

docker-compose --profile frontend up

When using profiles, you can seamlessly toggle between which services to run without needing to modify the file directly.

3. Using the --no-start Option

Another approach is using the Docker CLI directly by creating services without starting them. You could use:

docker-compose create db

This command creates the service but does not start it. It allows you to later selectively start services:

docker-compose start db

4. Modify Restart Policies

If you do not want a service to restart automatically if it exits, ensure you set appropriate restart policies. By default, services may restart under certain conditions. Setting a “never” restart policy can help control unexpected starts, thus:

version: '3.8'
services:
  web:
    image: nginx
    restart: "no"

This adjustment, however, only prevents the services from restarting under defined circumstances and not from starting during docker-compose up itself.

5. Custom Entry Scripts

In advanced scenarios, you may want to create custom entry scripts that check the conditions under which they should start, thus allowing more granular control over what begins when.

Conclusion

To prevent a service from automatically starting during docker-compose up, you can either comment out the services, utilize profiles, create without starting, adjust restart policies, or employ custom entry scripts. Each of these methods allows for varying levels of control suitable for different development needs.

If you regularly find yourself needing to enable or disable services dynamically, consider adopting profiles as a long-term strategy, as it provides a flexible and clean solution for managing service states in Docker Compose.

For further reading on managing services and understanding Docker Compose better, refer to the official Docker documentation.