11  Week 10 (4-Dez-2025)

11.1 Use Ansible to Modify an index.html file in Nginx Containers

11.1.1 Prepare the New index.html

  • Create the file to be copied later into the containers.

  • File /path/to/new_index.html

<html>
<head><title>Updated Nginx Page</title></head>
<body>
    <h1>Hello from Ansible!</h1>
</body>
</html>

11.1.2 Build a Docker Image from a Dockerfile

  • Exercise: Create a simple Dockerfile that uses the nginx base image and include the ssh server and python into the container.

  • Solution: Create a directory for your project.

mkdir nginx-ssh-container
cd nginx-ssh-container
  • Create a file named Dockerfile.
# Use the official Nginx image as the base
FROM nginx:latest

# Update package list and install OpenSSH server
RUN apt-get update && \
    apt-get install -y openssh-server && \
    mkdir /var/run/sshd

# Install Python
RUN apt-get update && \
    apt-get install -y python3 python3-pip

# Set a password for the root user (replace 'password' with a secure password)
RUN echo 'root:password' | chpasswd

# Allow root login via SSH
RUN sed -i 's/#PermitRootLogin prohibit-password/PermitRootLogin yes/' /etc/ssh/sshd_config

# Expose ports for Nginx and SSH
EXPOSE 80 22

# Start both SSH and Nginx services
CMD service ssh start && nginx -g 'daemon off;'
  • Build the Docker image.
docker build -t my-nginx-with-ssh .
  • Expected Output: Successful build message with a new image tagged as my-nginx-with-ssh.

11.1.3 Setup Two Nginx Containers

  • Deploy two Nginx containers based on the created Docker image.
docker run -d -p 8081:80 -p 2221:22 --name nginx1 my-nginx-with-ssh
docker run -d -p 8082:80 -p 2222:22 --name nginx2 my-nginx-with-ssh
  • Verify the contents by accessing the Nginx containers in a browser:
    • For nginx1: http://localhost:8081
    • For nginx2: http://localhost:8082
  • Confirm that you can also login to those nginx servers. Use the password defined in the Dockerfile above.
ssh root@localhost -p 2221
ssh root@localhost -p 2222
  • Exit from both hosts.

11.1.4 Generate a SSH Key Pair

  • Generate a Key Pair (Private & Public Keys). This will allow you to connect (over SSH) to any host without a password.
  • When generating the keys, just press Enter on any inputs requests.
ssh-keygen -t rsa -b 4096 -C "ansible_control_machine"
  • Copy your public key into the nginx servers to be able to login without a password. Enter the password when needed.
  • After this step, you are now able to login into the nginx servers without password.
ssh-copy-id -i ~/.ssh/id_rsa.pub -p 2221 root@localhost
ssh-copy-id -i ~/.ssh/id_rsa.pub -p 2222 root@localhost
  • Login again to those nginx servers and confirm that you don’t need to enter the password anymore.
ssh root@localhost -p 2221
ssh root@localhost -p 2222

11.1.5 Create a New Ansible Playbook

  • Write an Ansible playbook to modify the index.html file inside the containers.

  • Create file update_nginx_index.yml

- name: Update index.html in Nginx containers
  hosts: nginx_containers
  tasks:
    - name: Ensure the new index.html exists inside the container
      copy:
        src: /path/to/new_index.html
        dest: /usr/share/nginx/html/index.html
        remote_src: no
  • Create file inventory.yml
all:
  hosts:
    nginx1:
      ansible_host: localhost
      ansible_port: 2221
      ansible_user: root
      ansible_python_interpreter: /usr/bin/python3
    nginx2:
      ansible_host: localhost
      ansible_port: 2222
      ansible_user: root
      ansible_python_interpreter: /usr/bin/python3
  children:
    nginx_containers:
      hosts:
        nginx1:
        nginx2:
  • Check that you can ping the hosts by executing the following command.
ansible -i inventory.yml -m ping
  • If you have success, now you can run the playbook.

11.1.6 Run the Playbook

  • Use the following command to execute the playbook and update the containers.
ansible-playbook -i inventory.yml update_nginx_index.yml

11.1.7 Expected Outcome

  • The index.html file inside both nginx1 and nginx2 containers is replaced with the custom version.

  • Restarting the containers reflects the updated content.

  • Verify by accessing the Nginx containers in a browser:

    • For nginx1: http://localhost:8081
    • For nginx2: http://localhost:8082

  • Both should display the updated message: “Hello from Ansible!”