In this section, we will delve into the concept of deployment automation, a critical component of Continuous Deployment (CD). Deployment automation ensures that software can be released to production environments reliably and frequently, with minimal manual intervention. This reduces the risk of human error and speeds up the deployment process.

1. Automated Deployment Scripts:

   • Scripts that automate the deployment process, including copying files, configuring environments, and restarting services.

2. Infrastructure as Code (IaC):

   • Managing and provisioning computing infrastructure through machine-readable definition files, rather than physical hardware configuration or interactive configuration tools.

3. Configuration Management Tools:

   • Tools like Ansible, Puppet, and Chef that automate the configuration of systems and applications.

4. Continuous Delivery vs. Continuous Deployment:

   • Continuous Delivery ensures that code changes are automatically prepared for a release to production.
   • Continuous Deployment goes a step further by automatically deploying every change that passes the automated tests to production.

• Consistency: Ensures that deployments are performed in the same way every time, reducing errors.
• Speed: Accelerates the deployment process, allowing for more frequent releases.
• Reliability: Reduces the risk of human error, making deployments more reliable.
• Scalability: Makes it easier to deploy to multiple environments and scale applications.

1. Install Jenkins:

   • Download and install Jenkins from Jenkins official website.

2. Create a New Job:

   • Open Jenkins dashboard.
   • Click on "New Item".
   • Enter a name for your job and select "Freestyle project".

3. Configure Source Code Management:

   • Under "Source Code Management", select "Git".
   • Enter the repository URL and credentials if required.

4. Add Build Steps:

   • Under "Build", click "Add build step" and select "Execute shell".
   • Add the necessary shell commands to build your project.

5. Add Post-Build Actions:

   • Under "Post-build Actions", click "Add post-build action" and select "Deploy to container".
   • Configure the deployment settings, such as the container type and the deployment path.

• Stopping the current application: Ensures that the application is not running during the deployment process.
• Copying new files: Copies the new build files from the Jenkins workspace to the application directory.
• Starting the application: Restarts the application to apply the new changes.

Objective: Use Ansible to automate the deployment of a web application.

Steps:

1. Install Ansible:

   • Follow the installation guide on the Ansible documentation.

2. Create an Inventory File:

   • Define the hosts where the application will be deployed.

   [webservers]
   server1 ansible_host=192.168.1.10 ansible_user=deploy
   server2 ansible_host=192.168.1.11 ansible_user=deploy
   

3. Write an Ansible Playbook:

   • Create a playbook to automate the deployment process.

   ---
   - name: Deploy web application
     hosts: webservers
     tasks:
       - name: Stop current application
         service:
           name: myapp
           state: stopped
   
       - name: Copy new files
         copy:
           src: /path/to/new/files/
           dest: /var/www/myapp/
           owner: www-data
           group: www-data
           mode: '0755'
   
       - name: Start application
         service:
           name: myapp
           state: started
   

4. Run the Playbook:

   • Execute the playbook to deploy the application.

   ansible-playbook -i inventory deploy.yml
   

• Inventory File:

  [webservers]
  server1 ansible_host=192.168.1.10 ansible_user=deploy
  server2 ansible_host=192.168.1.11 ansible_user=deploy
  

• Ansible Playbook:

  ---
  - name: Deploy web application
    hosts: webservers
    tasks:
      - name: Stop current application
        service:
          name: myapp
          state: stopped
  
      - name: Copy new files
        copy:
          src: /path/to/new/files/
          dest: /var/www/myapp/
          owner: www-data
          group: www-data
          mode: '0755'
  
      - name: Start application
        service:
          name: myapp
          state: started
  

• Run Command:

  ansible-playbook -i inventory deploy.yml
  

Deployment automation is a crucial aspect of Continuous Deployment, enabling consistent, reliable, and fast software releases. By leveraging tools like Jenkins and Ansible, you can automate the deployment process, reducing the risk of human error and increasing deployment frequency. In the next section, we will explore various deployment strategies to further enhance your deployment process.