Infrastructure as Code (IaC) is the practice of configuring, provisioning , and managing infrastructure resources using code. It is an integral component of DevOps methodology, facilitating the seamless orchestration of applications and their underlying infrastructure such as servers, virtual machines, databases, and networks.
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Project Structure and Organization
When handling projects, it's important to establish a well-organized directory structure to effectively manage your project and potential complexities. It's recommended to maintain distinct directories for various purposes and ensure a uniform format, style, and code structure.
Directory Structure
The recommended directory structure for any IaC project includes separating code, configuration, and documentation into organized folders. By following an organized directory structure, you make it easier for team members to locate and manage specific elements of your IaC project, maintain consistency, and collaborate effectively. It also facilitates version control and ensures that your project remains clear, maintainable, and scalable.
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Note: An IaC project typically undergoes multiple iterations to align with a company's specific project requirements, and its initial definition may not be entirely accurate.
Root Directory: The root directory of your IaC project typically contains high-level configuration files and important project-wide documentation. It may include files like "main.tf" (for Terraform) or "site.yml" (for Ansible) as the entry point for your IaC code.
Code Directory: This is where you store the actual IaC code. You should create subdirectories for different components or environments.
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Documentation Directory: It's a good practice to have a dedicated folder for documentation. This directory should contain files explaining the project's purpose, architecture, and usage, along with any user or developer guides.
Modules/Scripts Directory: If your IaC project is sufficiently complex, you may want to have a directory specifically for reusable modules, scripts, or functions. These can be shared and included in your code as needed.
Variables Directory: Store variable definitions in a dedicated directory. This can help keep variables separate from the code logic and make it easier to manage and change configurations.
Tests Directory: If your IaC project includes automated tests (highly recommended), place your test files or scripts in this directory. This helps ensure code reliability.
Infrastructure State Directory: Some IaC tools maintain state files that track the current state of deployed resources. Keep these files in a separate directory to prevent accidental modifications.
Secrets Directory (Optional): For security and separation of concerns, you may consider having a separate directory for managing secrets and sensitive data. Ensure strict access controls on this folder.
Logs and Reports Directory (Optional): If your IaC project generates logs or reports, you can have a directory for storing these files.
Bin or Scripts Directory (Optional): If you have utility scripts or binaries that assist in the IaC process, place them in this directory.
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Note: An IaC project typically undergoes multiple iterations to align with a company's specific project requirements, and its initial definition may not be entirely accurate. |
Naming Conventions
Establishing clear and consistent naming conventions for resources, files, and directories within your IaC project is crucial for enhancing project maintainability.
Here are some key considerations:
Resource Naming Conventions: Resources like servers, databases, and networking components should have names that reflect their purpose and attributes.
For example, use meaningful names like “web-server” or “database-prod” to make the resource context more evident.
File Naming Conventions: Maintain a consistent approach to naming your IaC files.
For example, if you’re using Terraform, use a prefix like “main.tf” for your primary configuration file, and then use descriptive file names for additional modules or configurations, such as “networking.tf” or “security-groups.tf”.
Consistency Across Environments: Maintain consistency in naming across different environments (e.g., development, staging, production) to avoid confusion.
For example, if you use “app-server-dev”, use “app-server-staging” and “app-server-prod” for similar resources in other environments.
Version Control Branch and Tag Naming: When managing your IaC project in version control (e.g., Git), consider naming branches and tags with descriptive names that indicate the purpose of a branch or release version.
For example, use “feature/add-ssl” or “v1.2-release”.
Use of Hyphens or Underscores: Choose either hyphens or underscores for separating words in names. Stick with one style throughout your project for consistency.
For example, either only use hyphens as in “web-server” or underscores as in “web_server”.
Avoid Special Characters and Spaces: Steer clear of special characters, spaces, and other non-alphanumeric characters in names, as they can lead to compatibility issues or confusion.
Repository Layout
Organizing your IaC code within your version control repository is essential for maintaining an efficient version control repository for your IaC project, making collaboration, version management, and project tracking smoother and more effective.
Here's a guide on how your IaC code should be structured within a version control repository, including best practices for branches and folders:
Branches
Master/Main Branch: The primary branch (often named "master" or "main") should contain the production-ready code. It should be stable and protected, allowing only approved changes to be merged into it.
Feature Branches: For each new feature, enhancement, or bug fix, create a dedicated feature branch. Use clear and descriptive names, such as "feature/add-load-balancer" or "bugfix/fix-database-connection."
Environment-Specific Branches: Maintain branches for different environments, such as "staging" or "development." These branches can be used for environment-specific configurations.
Release Branches: When preparing for a new release, create a release branch (e.g., "release/v1.0"). Only bug fixes and essential changes should be merged into release branches.
Hotfix Branches: For critical issues in production, create hotfix branches (e.g., "hotfix/ssl-certificate-expiry") to address and deploy immediate fixes.
Folder
Code Folder: Organize your IaC code within a dedicated folder to keep it separate from other project assets.
Modules Folder: If you use reusable modules, create a "modules" folder to store them.
Infrastructure Provisioning
Possible Sub-pages/topics:
Explanation of IaC Language (Terraform and Ansible terminologies)
Creating Infrastructure Resources
Resource Dependencies and Order(?)
Configuration Management
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Variables Folder: Keep variable definitions in a "variables" folder for clarity.
Tests Folder: Store your test files or scripts in a "tests" folder to ensure that your code is thoroughly tested.
Documentation Folder: Include a folder for documentation. This is where you can store architecture diagrams, user guides, and other project documentation.
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Note: Unlike a directory, which can store files, subdirectories, and other directories, a folder can only store files. |
Versioning
Semantic Versioning: Adhere to semantic versioning principles for your IaC code to clearly communicate the impact of changes. Versions typically follow the format “X.Y.Z”, where:
X is a major version
Y is a minor version
Z is a patch version
Tags for Releases: Tag releases with version numbers (e.g., "v1.0.0") to make it easy to reference specific releases in the future.
Commit Messages: Write informative and concise commit messages. Describe the purpose of the change, its impact, and any relevant details. Follow a consistent style guide for commit messages.
Pull Request Reviews: Require code reviews for all pull requests. This ensures that changes are thoroughly examined and conform to project standards.
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Infrastructure Provisioning
Infrastructure Provisioning is a fundamental aspect of IaC where the defined infrastructure is created, deployed, and managed as code. Rather than relying on manual and error-prone processes, IaC empowers teams to automate infrastructure provisioning through code, ensuring a highly systematic and repeatable approach.
By embracing Infrastructure Provisioning as a core tenet of IaC, organizations can unlock the advantages of agility, cost-efficiency, and reliability in managing their digital infrastructure. This approach transforms infrastructure management from a manual, error-prone process into a streamlined, automated, and agile practice, aligning it with the principles and practices that have revolutionized software development.
Creating Infrastructure Resources
The core of infrastructure provisioning is defining the resources you need for your project, such as virtual machines, databases, networks, and more. In your IaC code, you describe the desired state of these resources, specifying their attributes, relationships, and configurations.
Dinesh Amatya can you provide high-level instructions on how we provision resources in IT-Conductor that is somehow true for all IaC/migration projects regardless of what we are migrating (if possible)?
Explore the following scenarios illustrating resource provisioning during migrations:
Resource Dependencies and Order
Some IaC tools handle resource dependency management intelligently, deploying resources in a way that adheres to the dependencies and relationships among defined resources. Familiarize yourself with your chosen tool's behavior in this regard.
In Terraform, you can utilize
depends_onandcountparameters to control the creation order. This meta-argument handles hidden resource or module dependencies that Terraform cannot automatically infer.
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Note: You only need to explicitly declare a dependency when a resource or module relies on the behavior of another resource without utilizing any data from that resource in its parameters. |
In Ansible, you can structure your playbooks to execute tasks in the desired sequence. By structuring your playbooks effectively, you can enforce a logical order of operations, execute configurations, and maintain the overall flow of your automation, ensuring that your infrastructure and applications are configured, deployed, and managed in a well-defined and organized manner.
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Configuration Management
Configuration management is a pivotal aspect of Infrastructure as Code (IaC) that ensures your infrastructure is consistently configured and maintained to meet your desired state.
Managing Configuration Files
Secrets Management
Parameterization and Variables
Setting Up IaC Environment
Possible Sub-pages/topics:
Pre-requisite Requirements
Installation and Configuration
Environment Variables
IaC Tools
Terraform
Ansible