Infrastructure as Code (IaC)
One of the most exciting developments in technology today is infrastructure as code (IaC). When your infrastructure (often in the cloud) is all virtualized, it can be easily created (and destroyed) as well as maintained by using scripts (code). This makes it possible for you to “spin up” test environments or pilot tests with ease. Think about how much easier it is to create a duplicate site for high availability (HA) needs when using IaaS and IaC than when using physical devices.
The large public cloud providers make it simple for you to implement IaC. They provide tools (such as CloudFormation from AWS) that permit you to easily generate the code required to script the creation of useful (and even complex) infrastructures. Thanks to this capability, you can easily automate—and even orchestrate—common networking tasks that used to take weeks or months to carry out. For example, say that you need to spin up 50 servers for a test project. Thanks to IaC, you can now do this with a few clicks of the mouse instead of using a massive (and often) expensive deployment of physical servers.
There is a difference between automation and orchestration:
Automation refers to the automated completion of a task or tasks.
Orchestration refers to the scheduling and monitoring of many different automations. It is, basically, automating the automation.
Key components of automation in IaC include playbooks, templates, and reusable tasks, which facilitate the creation, maintenance, and scaling of infrastructure in a consistent manner. Additionally, automation helps address challenges such as configuration drift, compliance, and upgrades, and supports dynamic inventories for flexible resource management. Here are more details on the key components and advantages of automation with IaC:
Playbooks: Playbooks are a fundamental tool in IaC automation, particularly in tools like Ansible. They provide a structured way to define a series of tasks that automate the provisioning, configuration, and management of infrastructure. Playbooks are written in YAML and describe the desired state of the infrastructure in a declarative manner. This allows for complex workflows to be automated, such as deploying applications, configuring servers, and managing network devices.
Templates: Templates in IaC are used to define infrastructure resources in a reusable and consistent manner. Tools like Terraform and AWS CloudFormation utilize templates to describe cloud resources and their relationships. These templates can include variables, allowing for parameterization and flexibility in resource configurations. For example, a template might define a virtual machine with specific attributes like instance type, security groups, and attached storage. By using templates, organizations can ensure that infrastructure components are created with a consistent configuration across different environments, reducing the risk of configuration errors and making it easier to replicate and scale infrastructure.
Reusable tasks: Reusable tasks are a key aspect of IaC automation that promote efficiency and maintainability. In tools like Ansible, reusable tasks can be defined in roles, which are collections of tasks, variables, and templates organized in a structured format. Roles can be shared across multiple playbooks and projects, allowing for the reuse of common configurations and deployment steps. For example, a role might encapsulate the tasks required to set up a web server, including installing packages, configuring services, and managing firewall rules.
Configuration drift: Configuration drift occurs when the actual state of the infrastructure deviates from the desired state defined in the IaC. This can happen due to manual changes, system updates, or environmental factors. Automation in IaC helps mitigate configuration drift by regularly applying the desired state to the infrastructure. Tools like Terraform and Ansible can perform periodic checks and reapply configurations to ensure consistency. This not only helps maintain the reliability and predictability of the infrastructure but also reduces the time and effort required to troubleshoot and resolve issues caused by drift. Automation ensures that the infrastructure remains aligned with the defined state, minimizing the risks associated with unintended changes.
Compliance: Compliance with industry standards and regulatory requirements is a critical aspect of infrastructure management. Automation in IaC enables organizations to enforce compliance by embedding policies and controls directly into the infrastructure code. For example, security configurations, access controls, and data protection measures can be defined in the IaC templates and playbooks. Automated tools can continuously monitor the infrastructure for compliance with these policies, generating reports and alerts when deviations occur.
Upgrades: Upgrading infrastructure components, such as software versions, operating systems, and hardware configurations, can be a complex and error-prone process. IaC automation simplifies upgrades by allowing organizations to define the desired state of the infrastructure, including the required versions and configurations. Upgrades can be tested in a staging environment using the same IaC definitions before being applied to production, reducing the risk of disruptions.
Dynamic inventories: Dynamic inventories are a feature of IaC automation that allows the infrastructure to be dynamically discovered and managed based on current configurations and states. This is particularly useful in cloud environments, where resources can be created and terminated frequently. Tools like Ansible support dynamic inventories, which can query cloud providers or other data sources to generate an up-to-date list of resources for configuration management tasks.
Because the C in IaC stands for code, it is of no surprise that IaC systems tend to take advantage of source control systems. These systems tend to feature the following:
Version control: Version control is at the heart of source control systems and is vital for managing IaC. It enables teams to track changes to infrastructure code over time, maintaining a history of modifications, additions, and deletions. Each change is recorded with a unique identifier, often called a commit, along with metadata such as the author, timestamp, and a message describing the change.
Central repository: A central repository in a source control system acts as the single source of truth for all infrastructure code. This repository stores the master copies of the code and provides a central location where all team members can access, contribute to, and collaborate on the infrastructure codebase.
Conflict identification: Conflict identification is an essential feature of source control systems, especially in collaborative IaC environments, where multiple team members may work on the same code simultaneously. Conflicts occur when changes made by different users overlap or are incompatible with each other.
Branching: Branching is a powerful feature of source control systems that allows teams to create isolated copies of the codebase for different purposes. This is particularly useful in IaC environments for managing multiple streams of development and experimentation without affecting the main codebase.