Ansible & Terraform

What is Ansible?

• It is an open-source IT automation engine that simplifies configuration management, application deployment, and task orchestration.

• It uses simple, human-readable YAML syntax to define tasks in "playbooks," and its agent-less architecture connects to managed nodes over SSH to automate tasks like software installation and system updates.

• Ansible helps IT teams save time, increase efficiency, and reduce human error by managing infrastructure and automating complex workflows.  

Key Features and Functions

• Automation Engine: Ansible automates a wide range of IT needs, from simple tasks to complex orchestration of multi-tier applications. 

• Agent-less Architecture: It connects to managed nodes via SSH, so there is no need to install or maintain agents on the target systems. 

• Playbooks: These are files written in YAML that define a series of tasks, which are executed by Ansible to achieve a desired state on the managed nodes. 

• Idempotent: Playbooks are designed to be idempotent, meaning they will only make changes if necessary to reach the desired state, preventing unintended modifications. 

• Simplicity: The use of YAML syntax makes playbooks easy to write and understand, even for those without extensive programming experience. 

• Cross-platform: Ansible can manage various operating systems and cloud environments, making it a versatile tool for diverse IT infrastructures. 

• Control Node and Managed Nodes: The control node is the machine where Ansible is installed and runs from. The managed nodes (or "hosts") are the remote servers, network devices, or cloud platforms that Ansible automates and controls.

• Modules: These are the reusable scripts that perform specific tasks, such as installing a package, copying a file, or starting a service. Ansible provides a large library of pre-built modules for a wide variety of functions.

• Inventory: This is a simple text file (in INI or YAML format) that lists all the managed nodes and organizes them into groups for easier management. For cloud environments, dynamic inventories can be used to pull information from cloud provider APIs.

Common Use Cases

• Provisioning: Automating the setup of new servers and cloud infrastructure. 

• Configuration Management: Ensuring that systems are configured consistently and correctly. 

• Application Deployment: Automating the process of deploying applications to servers. 

• Orchestration: Coordinating complex workflows across multiple systems and services. 

• Security and Compliance: Helping to enforce security policies and maintain compliance across the environment. 

What is Terraform?

• It is an open-source tool for Infrastructure as Code (IaC) that automates the provisioning and management of cloud and on-premises infrastructure. 

• It allows admins to define their desired infrastructure using configuration files written in its declarative language (HashiCorp Configuration Language - HCL), and Terraform figures out how to create and maintain it. 

• This enables building, changing, and versioning infrastructure safely and efficiently across various platforms like AWS, Azure, and Google Cloud.  

How Terraform works

The process of using Terraform follows a simple, repeatable workflow: 

1. Write: You write configuration files using HashiCorp Configuration Language (HCL) to define the desired state of your infrastructure.

2. Plan: You run the Terraform plan command, which compares your configuration files to the actual state of your infrastructure. It then generates an execution plan that describes exactly what actions it will take to match the desired state.

3. Apply: You run the Terraform apply command, which executes the plan and provisions or modifies your infrastructure accordingly.

4. Manage: Terraform stores the state of your managed infrastructure in a terraform.tfstate file, which is used for tracking changes and ensuring consistency over time.

Key Components and Features

• Declarative Language (HCL): With a declarative approach, you describe what you want your infrastructure to look like, not how to build it step-by-step. Terraform automatically figures out the correct sequence of operations and resource dependencies.

• Providers: These are plugins that enable Terraform to interact with different cloud platforms and services through their APIs. Terraform has thousands of providers for major cloud platforms like AWS, Azure, and Google Cloud, as well as for many other services like Kubernetes, GitHub, and Splunk.

• Modules: These are reusable containers for multiple resources that are often used together. Modules simplify complex configurations and promote standardization by allowing you to define a configuration once and use it across many environments.

• Multi-Cloud and Hybrid Support: Unlike cloud-specific tools, Terraform is cloud-agnostic, allowing a single configuration to manage resources across multiple providers and on-premises environments

Common Use Cases

• Multi-Cloud Deployment: Manage infrastructure across multiple cloud providers with a single, consistent workflow to avoid vendor lock-in.

• Multi-Tier Application Deployment: Provision all the components for complex applications, such as load balancers, databases, and application servers, in a single, coordinated process.

• Self-Service Infrastructure: Allow development teams to provision their own standardised and approved infrastructure environments on demand using pre-defined modules.

• Environment Standardisation: Create and tear down temporary development or testing environments that are consistent with production.