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Ruby on Rails on CloudFlow

Learn how to run a Ruby on Rails app at the edge for low latency and high availability. You can use our repo as a template, or perform the steps yourself using the Kubernetes dashboard or kubectl commands.

Step by Step

Following are step-by-step instructions to deploy a Ruby on Rails application to the edge on CloudFlow. We'll Dockerize it, and deploy it on CloudFlow.


  • You need Docker installed so that you can build a docker image, and Ruby, Rails, and SQLite installed for testing locally.

Create the Ruby on Rails App

Create a new directory for your app.

mkdir my-rubyonrails-app
cd my-rubyonrails-app

Initialize the Ruby on Rails application with the following commands:

rails new hello_world
cd hello_world

Run the Ruby on Rails application locally with the following command:

# On Windows
ruby bin/rails server
# On Linux/Mac
bin/rails server

Now navigate to http://localhost:3000 in your browser to see the Ruby on Rails app running.


After deploying on CloudFlow and using your own domain name(s) you will need to edit the config.hosts setting in my_rubyonrails_app/hello_world/config/environments/development.rb to be your domain name(s). For example, if your domain name is (or including subdomains such as, you would change it to the following line:

  # Allow hosts
config.hosts << /[a-z0-9-.]+\.example\.com/

Dockerize It

Let's build the container image that we'll deploy to CloudFlow. First make a Dockerfile in your hello_world directory with the following content.

# Use the latest Ruby image from Docker Hub (
FROM ruby:latest

WORKDIR /hello_world
COPY . /hello_world

# Run bundle install to install the Ruby dependencies.
RUN bundle install

# Install Yarn.
RUN curl -sS | apt-key add -
RUN echo "deb stable main" | tee /etc/apt/sources.list.d/yarn.list
RUN apt-get update && apt-get install -y yarn

# Run yarn install to install JavaScript dependencies.
RUN yarn install --check-files

# Export port 3000

CMD ["rails", "server", "-b", ""]

Build and tag it.

docker build . -t

Launch it locally to test it.

docker run -p 3000:3000
curl http://localhost:3000

Push It

Push it to GitHub Packages. This makes it available to CloudFlow.

docker push

Be sure to make it public. To see your packages and make this change, visit

Deploy It

Next, use the Create Project command in the CloudFlow Console in order to deploy your new container. Use the image name with port 3000.

See the pods running on CloudFlow's network with either the Kubernetes dashboard or kubectl get pods -o wide. The -o wide switch shows where your app is running according to the default AEE location optimization strategy. Your app will be optimally deployed according to traffic. In lieu of significant traffic, your deployment will be made to default locations.

Try kubectl logs POD to see the log message reporting that the server is listening on port 3000:

=> Booting Puma
=> Rails 7.0.4 application starting in development
=> Run `bin/rails server --help` for more startup options
Puma starting in single mode...
* Puma version: 5.6.5 (ruby 3.1.3-p185) ("Birdie's Version")
* Min threads: 5
* Max threads: 5
* Environment: development
* PID: 1
* Listening on

Finally, follow the instructions that configure DNS and TLS.

See What You've Built

See the sample app you've built by visiting the https://YOUR.DOMAIN.COM, substituting YOUR.DOMAIN.COM according to your DNS and HTTPS configuration.