Docker + Docker Compose + Ansible

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Flask Application Deployment using Ansible roles and Docker-Compose

1. Run the "setup.sh" file given in the path to install the required dependencies before starting the challenge.

2. A Flask application named "app.py" is given in the path.

3. Create an Ansible role named "Installation" in the path "/etc/ansible/roles" to install docker-compose.

4. Write an Ansible playbook named "creation.yaml" in the path , to perform the following tasks:

1. Using "file" and "copy" modules, create a Multi-stage "Dockerfile" in the path to 

- Dockerize the given Flask application with "python:alpine3.7" as its base image, using the given 'requirements.txt' file. 

- Build an image using "postgres" as its base image.

2. Using "file" and "copy" modules, create a "docker-compose.yaml" file in the path which creates two services named 

- The "flask" service should run an "flask_image" image as a container named "flask_container" and expose it to port 5000.

- The "db" service should run an "postgres_image" image as a container named "postgres_container" and expose it to port 5476.

5. Write another Ansible playbook named "execute.yaml" in the path, to perform the following tasks using appropriate Dockerfile

- Import the "creation.yaml" playbook. 

- Include the created "installation" role.

- Build a Docker image named "flask_image" using the created Dockerfile. 

- Build a Docker image named "postgres_image" using the created Dockerfile.

- Run the "docker-compose.yaml" file.

6. Finally, run the "execute.yaml" playbook and check whether the Flask application is running in the specified port 5000.

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SOLUTION

1. create the Ansible role

            mkdir etc/ansible/roles

            cd etc/ansible/roles

            ansible-galaxy role init Installation

 

2. create the creation.yaml, to create Dockerfile and docker-compose.yaml file

---

- name: Create Dockerfile and docker-compose files

  hosts: localhost

  tasks:

    - name: Create Dockerfile

      copy:

        dest: ./Dockerfile

        content: |

          FROM python:alpine3.7 AS flask_img

          WORKDIR /app

         

          COPY requirements.txt /app

          RUN pip install -r requirements.txt

          COPY app.py .

          EXPOSE 5000

          ENV FLASK_APP=app.py

          CMD ["flask", "run", "--host", "0.0.0.0"]

          # ------------------------------------

          # ------------------------------------

          FROM postgres AS postgres_img

          ENV POSTGRES_DB myDB

          ENV POSTGRES_USER myuser

          ENV POSTGRES_PASSWORD mypassword

   

    - name: Create docker-compose

      copy:

        dest: ./docker-compose.yaml

        content: |

          version: '3.4'

          services:

            flask:

              image: flask_img

              container_name: flask_cont

              ports:

                - 5000:5000

            db:

              image: postgres_img

              container_name: postgres_cont

              ports:

                - 5476:5476

3. create the execute.yaml file

---

- name: Import creation.yml playbook

  import_playbook: creation.yaml

- name: Execute all tasks

  hosts: localhost

  tasks:

    - name: Include created role

      include_role:

        name: etc/ansible/roles/Installation

    - name: Build flask_img using Dockerfile

      command: docker build --target flask_img -t flask_img .

      become: true

    - name: Build postgress_img using Dockerfile

      command: docker build --target postgres_img -t postgres_img .

      become: true

    - name: Build docker-compose file using Dockerfile

      command: docker-compose up -d

# execute the playbooks using

# this is optional as this will create the Dockerfile and docker-compose file

ansible-playbook creation.yaml 

# execute this playbook mainly

ansible-playbook execute.yaml

# check the url for the flask application

curl http://localhost:5000