Deploying a Software-as-a-Service (SaaS) application nationwide is challenging yet rewarding. Automation is crucial in ensuring the deployment is repeatable, scalable, and efficient. In this guide, we’ll walk you through the process of automating the deployment of a nationwide SaaS application using Ansible and AWS. We’ll cover everything from preparing the infrastructure with Terraform to executing the Ansible playbook and cleaning the environment.

Preparing the AWS Infrastructure with Terraform

Before diving into Ansible, we must set up the necessary AWS infrastructure. Terraform is an excellent tool because it allows us to define and manage cloud resources as code.

  1. Define the Terraform Configuration:
    • Create a main.tf file to define your AWS infrastructure, including VPCs, subnets, EC2 instances, security groups, and more.
    • Use Terraform modules to keep your configuration DRY (Don’t Repeat Yourself) modular.
  2. Initialize Terraform:
    • Run terraform init to initialize the working directory and download the necessary providers.
  3. Plan and Apply the Configuration:
    • Use terraform plan to preview the changes.
    • Execute terraform apply to provision the AWS infrastructure.
  4. Output Values:
    • Capture key outputs like EC2 instance IDs, security group IDs, and public IPs, which will be used later in Ansible.

Configuring the Ansible Environment for Automation

With the infrastructure in place, we can now set up our Ansible environment for automation.

  1. Install Ansible:
    • Install Ansible on your control machine using package managers like apt or yum or via pip.
  2. Set Up the Directory Structure:
    • Organize your Ansible project with directories like inventories, roles, playbooks, and group_vars.
  3. Configure the Ansible Inventory:
    • Define the inventory of your AWS instances, grouping them by role (e.g., web servers, database servers).

Creating the Structure of the Ansible Role ‘humangov_webapp’

Ansible roles allow you to group tasks and variables logically. Here, we’ll create the role humangov_webapp to manage the web application deployment.

  1. Create the Role Structure:
    • Use ansible-galaxy init humangov_webapp to generate the role structure.
    • The structure includes directories like tasks, handlers, templates, and files.
  2. Define Tasks in tasks/main.yml:
    • Break down the deployment process into discrete tasks, such as installing packages, configuring Nginx, and deploying the application code.
  3. Set Up Handlers:
    • Define handlers for restarting services like Nginx and Systemd when configurations change.

Defining Ansible Configuration Files

Ansible configuration files (ansible.cfg) allow you to fine-tune Ansible’s behavior.

  1. Set Up ansible.cfg:
    • Configure inventory paths, SSH settings, and callback plugins.
    • Optimize settings for parallelism and verbosity based on your deployment size and complexity.
  2. Manage Variables in group_vars/:
    • Define environment-specific variables in group_vars to manage differences between staging, production, and other environments.

Managing AWS Credentials and Testing Connectivity

Ansible requires access to AWS resources, which means managing credentials securely.

  1. Configure AWS Credentials:
    • Use AWS CLI or environment variables to set up your credentials.
    • Alternatively, use Ansible Vault to encrypt sensitive information.
  2. Test Connectivity:
    • Run a simple Ansible ping command to ensure you can connect to your AWS instances.

Creating and Configuring Ansible Tasks for Deployment

With everything set up, it’s time to create and configure Ansible tasks to deploy your SaaS application.

  1. Install Required Packages:
    • Create tasks to install necessary software like Python, Nginx, and any dependencies for your application.
  2. Deploy Application Code:
    • Use tasks to pull the latest application code from a repository, place it in the correct directory, and set the appropriate permissions.
  3. Configure Application Settings:
    • Use templates or variables to configure application settings, environment variables, and service files.

Defining Jinja2 Templates for Systemd and Nginx Services

Jinja2 templates are potent tools for dynamically generating configuration files.

  1. Create Systemd Service Templates:
    • Define a Jinja2 template for the Systemd service managing your application.
    • Ensure it includes the necessary commands for starting, stopping, and restarting the service.
  2. Define Nginx Configuration Templates:
    • Create a Jinja2 template for Nginx that defines server blocks, proxy settings, and SSL configurations.
  3. Deploy Templates with Ansible:
    • Use the template module in Ansible to deploy these templates to the appropriate locations on your AWS instances.

Executing the Ansible Playbook and Troubleshooting

With all tasks and configurations in place, it’s time to execute the Ansible playbook.

  1. Run the Playbook:
    • Execute your playbook with ansible-playbook and monitor the output for any issues.
  2. Troubleshoot Failures:
    • Review the verbose output for failed tasks and resolve connectivity problems, misconfigurations, or missing dependencies.
  3. Verify Deployment:
    • Ensure the application is running by accessing it via a web browser or API calls.

Cleaning Up and Destroying the Infrastructure with Terraform

Once the deployment is verified, you should clean up the environment, especially in a testing or staging setup.

  1. Destroy Infrastructure:
    • Use terraform destroy to tear down the AWS resources created earlier.
    • Confirm that all resources have been removed to avoid unnecessary costs.
  2. Review Logs and Reports:
    • Ensure all actions are logged and review any reports generated during deployment for future reference.

References

Automate Ansible playbook deployment with Amazon EC2 and GitHub

Security in a multi-account environment