Quickstart with Docker Compose

This quickstart shows you how to set up Flower using Docker Compose in a single command, allowing you to focus on developing your application without worrying about the underlying infrastructure.

You will also learn how to easily enable TLS encryption and persist application state locally, giving you the freedom to choose the configuration that best suits your project’s needs.

Prérequis

Before you start, make sure that:

  • The flwr CLI is installed locally.

  • The Docker daemon is running.

  • Docker Compose V2 is installed.

Step 1: Set Up

  1. Clone the Docker Compose complete directory:

    $ git clone --depth=1 --branch v1.14.0 https://github.com/adap/flower.git _tmp \
            && mv _tmp/src/docker/complete . \
            && rm -rf _tmp && cd complete

  2. Create a new Flower project (PyTorch):

    $ flwr new quickstart-compose --framework PyTorch --username flower

  3. Export the path of the newly created project. The path should be relative to the location of the Docker Compose files:

    $ export PROJECT_DIR=quickstart-compose

    Setting the PROJECT_DIR helps Docker Compose locate the pyproject.toml file, allowing it to install dependencies in the ServerApp and ClientApp images correctly.

Step 2: Run Flower in Insecure Mode

To begin, start Flower with the most basic configuration. In this setup, Flower will run without TLS and without persisting the state.

Note

Without TLS, the data sent between the services remains unencrypted. Use it only for development purposes.

For production-oriented use cases, enable TLS for secure data transmission.

Open your terminal and run:

$ docker compose up --build -d
Understand the command

  • docker compose: The Docker command to run the Docker Compose tool.

  • --build: Rebuild the images for each service if they don’t already exist.

  • -d: Detach the containers from the terminal and run them in the background.

Step 3: Run the Quickstart Project

Now that the Flower services have been started via Docker Compose, it is time to run the quickstart example.

To ensure the flwr CLI connects to the SuperLink, you need to specify the SuperLink addresses in the pyproject.toml file.

  1. Add the following lines to the quickstart-compose/pyproject.toml:

    quickstart-compose/pyproject.toml
    [tool.flwr.federations.local-deployment]
address = "127.0.0.1:9093"
insecure = true

  2. Run the quickstart example, monitor the ServerApp logs and wait for the summary to appear:

    $ flwr run quickstart-compose local-deployment --stream

Step 4: Update the Application

In the next step, change the application code.

  1. For example, go to the task.py file in the quickstart-compose/quickstart_compose/ directory and add a print call in the get_weights function:

    quickstart-compose/quickstart_compose/task.py
    # ...
def get_weights(net):
    print("Get weights")
    return [val.cpu().numpy() for _, val in net.state_dict().items()]


# ...

  2. Rebuild and restart the services.

    Note

    If you have modified the dependencies listed in your pyproject.toml file, it is essential to rebuild images.

    If you haven’t made any changes, you can skip this step.

    Run the following command to rebuild and restart the services:

    $ docker compose up --build -d

  3. Run the updated quickstart example:

    $ flwr run quickstart-compose local-deployment --stream

    In the ServerApp logs, you should find the Get weights line:

    INFO :      Starting logstream for run_id `10386255862566726253`
INFO :      Starting Flower ServerApp
WARNING :   Option `--insecure` was set. Starting insecure HTTP channel to superlink:9091.
🎊 Successfully installed quickstart-compose to /app/.flwr/apps/flower.quickstart-compose.1.0.0.35361a47.
Get weights
INFO :      Starting Flower ServerApp, config: num_rounds=3, no round_timeout

Step 6: Run Flower with TLS

  1. To demonstrate how to enable TLS, generate self-signed certificates using the certs.yml Compose file.

    Important

    These certificates should be used only for development purposes.

    For production environments, use a service like Let’s Encrypt to obtain your certificates.

    Run the command:

    $ docker compose -f certs.yml run --rm --build gen-certs

  2. Add the following lines to the quickstart-compose/pyproject.toml:

    quickstart-compose/pyproject.toml
    [tool.flwr.federations.local-deployment-tls]
address = "127.0.0.1:9093"
root-certificates = "../superlink-certificates/ca.crt"

  3. Restart the services with TLS enabled:

    $ docker compose -f compose.yml -f with-tls.yml up --build -d

  4. Rerun the quickstart-compose project:

    $ flwr run quickstart-compose local-deployment-tls --stream

Step 7: Add another SuperNode and ClientApp

You can add more SuperNodes and ClientApps by uncommenting their definitions in the compose.yml file:

compose.yml
  # other service definitions

  supernode-3:
    image: flwr/supernode:${FLWR_VERSION:-1.14.0}
    command:
      - --insecure
      - --superlink
      - superlink:9092
      - --clientappio-api-address
      - 0.0.0.0:9096
      - --isolation
      - process
      - --node-config
      - "partition-id=1 num-partitions=2"
    depends_on:
      - superlink

  clientapp-3:
    build:
      context: ${PROJECT_DIR:-.}
      dockerfile_inline: |
        FROM flwr/clientapp:${FLWR_VERSION:-1.14.0}

        USER root
        RUN apt-get update \
            && apt-get -y --no-install-recommends install \
            build-essential \
            && rm -rf /var/lib/apt/lists/*
        USER app

        WORKDIR /app
        COPY --chown=app:app pyproject.toml .
        RUN sed -i 's/.*flwr\[simulation\].*//' pyproject.toml \
          && python -m pip install -U --no-cache-dir .

        ENTRYPOINT ["flwr-clientapp"]
    command:
      - --insecure
      - --clientappio-api-address
      - supernode-3:9096
    deploy:
      resources:
        limits:
          cpus: "2"
    stop_signal: SIGINT
    depends_on:
      - supernode-3

If you also want to enable TLS for the new SuperNode, uncomment the definition in the with-tls.yml file:

with-tls.yml
  # other service definitions

  supernode-3:
    command:
      - --superlink
      - superlink:9092
      - --clientappio-api-address
      - 0.0.0.0:9096
      - --isolation
      - process
      - --node-config
      - "partition-id=1 num-partitions=2"
      - --root-certificates
      - certificates/superlink-ca.crt
    secrets:
      - source: superlink-ca-certfile
        target: /app/certificates/superlink-ca.crt

Restart the services with:

$ docker compose up --build -d
# or with TLS enabled
$ docker compose -f compose.yml -f with-tls.yml up --build -d

Step 9: Merge Multiple Compose Files

You can merge multiple Compose files into a single file. For instance, if you wish to combine the basic configuration with the TLS configuration, execute the following command:

$ docker compose -f compose.yml \
   -f with-tls.yml config --no-path-resolution > my_compose.yml

This will merge the contents of compose.yml and with-tls.yml into a new file called my_compose.yml.

Step 10: Clean Up

Remove all services and volumes:

$ docker compose down -v

Where to Go Next