What is Infrastructure as Code (IaC)?

Quick Definition: Infrastructure as Code is a set of machine-readable instructions that manage and provision hardware components and is used in place of manually interfacing with the hardware itself. IaC is a declarative approach to provision written in either JSON or YAML and treats hardware like software, which enables greater degrees of automation, scalability, and management efficiency. 

It's no secret that IT environments are continuing to grow in size and complexity. This means that managing, maintaining, and scaling the hardware is increasingly difficult. Infrastructure as Code (IaC) lightens the burden by automating hardware provisioning through a set of instructions that are read by an IaC interpreter, such as AWS CloudFormation or Ansible. The IaC interpreter then makes the necessary configuration on the hardware itself.

That is a 1,000-foot definition, but as IT experts, it’s important we get into the nuts and bolts of the IaC concept–which is exactly what this post will cover. First, let’s go over what IaC is and how it is implemented, and then explore a few real-world use cases.

What is Infrastructure as Code?

Infrastructure as Code (IaC) is a set of machine-readable instructions that manage and provision hardware components. It is used in place of manually interfacing with the hardware itself. IaC is a declarative approach to provision written in either JSON or YAML and treats hardware like software, providing greater degrees of automation, scalability, and management efficiency. 

Evolution and History of IaC

The evolution of IaC and the advent of cloud technology go hand in hand. However, some IaC technologies, such as Chef (2009), existed prior to the cloud, which allowed IT administrators to provision and automate on-site servers.

Next up, the advent of cloud technology such as AWS, Microsoft Azure, and Google Cloud Platform (GCP) revolutionized the way infrastructure was provisioned and managed. Cloud providers offered APIs for programmatically provisioning and configuring infrastructure resources, paving the way for the automation and scalability provided by IaC.

Lastly, we would be remiss to omit Kubernetes, a highly robust and scalable IaC solution. Containerization led by Docker cemented IaC by allowing software engineers to isolate, scale, and manage applications using nothing but code. This breakthrough allowed for declarative infrastructure management at scale.

While this timeline is not all-inclusive, it covers the three big leaps for IaC: Chef (and Puppet), cloud utilization, and containerization.

Key Concepts and Components

While there are several different flavors of IaC, such as AWS CloudFormation, Ansible, and Chef, all follow the same core concepts. Let’s highlight these similarities and focus on the essentials of IaC.

Declarative vs. Imperative IaC

Declarative Definition: Declarative IaC focuses on the desired state of the hardware without detailing step-by-step instructions of what needs to happen.

• Example: Let’s say you are configuring pods in Kubernetes and want to ensure three pods are replicated at all times. This code is simply defined within the YAML file using certain keywords, and the IaC interpreter knows how to execute the instructions.

• Advantages: The core advantage of declarative IaC is its simplicity. With declarative code, you generally know it will work the way you intend it to.

Imperative Definition: Imperative means you are providing step-by-step instructions for exactly what should happen. To remember it, pretend you are telling the computer, “It is imperative you follow these instructions!” That way, you remember imperative means step-by-step.

• Example: With imperative IaC, you might specify commands to create each resource individually, such as "create server," "configure security group," and "assign IP address."

• Advantages: The biggest advantage of imperative programming is you have granular access to the code execution. Building off that, it can also provide more flexibility in certain scenarios that require more invasive methods of control.

Infrastructure as Data

Infrastructure as Data refers to treating hardware configurations like pieces of data in code. For example, let’s say you provision a server with 16 GB of RAM, replicate it three times, and have a 3.2 GHz CPU. This configuration can be saved in a file, version-controlled, and then applied to other servers in other environments. That’s the power of infrastructure as data. 

Version Control and Collaboration

One of the best uses of IaC is that all the code is version-controlled. Version control refers to a programmatic system that keeps track of all changes, who made them, and the ability to revert back to any given changes. The most common one nowadays is undoubtedly GitHub.

One of IaC's most important aspects is its version control trait. It makes it far easier to revert to previous changes when a mistake is made in the script or collaborate with other contributors to the IaC. 

Automation and Orchestration

Automation and orchestration enable the efficient management and provisioning of infrastructure resources, contributing to increased reliability and scalability. One of the most common forms of IaC is a Dockerfile. A Dockerfile provides an image of how to run an application.

The container created by the Dockerfile can be put into a Kubernetes pod and given instructions on what to do if the connection is lost, how to access the internet, resource management, and much more. Orchestration's beauty lies in its ability to manage multiple application resources in the same environment.

What are Some Advantages and Disadvantages of IaC?

While IaC is ultimately the best way to go for large IT environments, there are still some disadvantages to consider. Let’s first walk through the major benefits and then consider some of the disadvantages.

Advantages of IaC 

Scalability: IaC enables automated provisioning and scaling of infrastructure resources, allowing organizations to easily accommodate changes in demand without manual intervention.

Consistency: With IaC, infrastructure configurations are defined in code, ensuring consistency across environments. This reduces the risk of configuration drift and makes deployments more reliable.

Reproducibility: Infrastructure configurations are version-controlled and can be replicated across different environments, making it easy to reproduce infrastructure setups reliably.

Disadvantages of IaC

Learning Curve: Adopting IaC often requires training and skill development for teams for teams that have never worked with it before. IaC’s inherent complexity can lead to a steep learning curve and long troubleshooting times.

Complexity: Implementing IaC can introduce complexity, especially in large-scale environments or when managing intricate infrastructure setups. Managing the complexity of IaC configurations and workflows can be challenging.

Risk of Misconfiguration: Lastly, while IaC reduces the risk of human error, misconfigurations in infrastructure code can still occur, leading to potential security vulnerabilities or operational issues. For example, the IaC file may involuntarily leave a port open, thus opening up a vector of cyber attack.

How Do You Implement IaC?

Implementing IaC is a complex and time-consuming process, but the benefits will enhance your IT hardware’s capability, maintenance, and scalability. Several steps are necessary to establish a successful IaC shop. Let’s run through some of the steps to provide a high-level understanding of how this can be done. 

Choose the Right IaC Software

Several different IaC tools are available that fit any hardware need. If your organization is on the cloud, then the best bet would be AWS CloudFormation, Azure Resource Management Templates, or Google Cloud Deployment Manager.

While the aforementioned are proprietary to their respective cloud, several options are platform agnostic. For example, Kubernetes, Chef, Ansible, and Terraform can all be used to adapt your hardware to an IaC environment.

Best Practices and Patterns

IaC has certain best practices that should be adhered to at all times. Let’s review some of the most prominent aspects of IaC.

Version Control: One of the most important aspects of IaC is ensuring all IaC is stored in a code repository. By keeping a record of the source code and all of its changes, it is easier to roll back to previous versions, keep track of who committed what, and collaborate as a team. The most common VC systems are GitHub and BitBucket.

Modularization: When developing IaC scripts, it is important to keep the contents as generic as possible. Doing so will allow other developers to easily use the file for their own IT resources. This can be done by using parameterization and defining reusable components.

Idempotence: In computer science, idempotence refers to an operation that has zero side effects when executed multiple times. For example, executing a GET request is idempotent because it retrieves data without affecting any other code. A POST request, however, is not idempotent because it adds data to a database. In summary, idempotence means that performing an operation multiple times will have the same effects as performing it once.

When writing IaC scripts, keep this concept in the back of your mind. IaC scripts are meant to be run multiple times. when possible, make sure each operation is idempotent to mitigate the risk of unintended side effects.

Now that we’ve reviewed a few best practices for IaC let’s examine some concrete examples to bring the subject home. 

Real-World Use Cases of IaC

Infrastructure as Code is used widely in virtually every industry to facilitate automation, scalability, and maintainability. Here are a few examples that highlight the benefits further. 

Cloud Infrastructure Provisioning

Organizations use IaC to provision and manage cloud infrastructure resources such as virtual machines, storage, networking components, and databases. The most widely used cloud providers are AWS, GCP, and Azure. By defining infrastructure configurations as code, teams can quickly deploy and scale infrastructure resources while maintaining consistency and repeatability.

Configuration Management

IaC tools such as Ansible, Puppet, and Chef are used for configuration management tasks, including software installation, configuration, and maintenance across servers and environments. With IaC, teams can ensure servers are configured consistently and according to desired specifications, reducing manual errors and speeding up deployments.

Continuous Integration/Continuous (CI/CD)

IaC plays a crucial role in CI/CD pipelines by automating the deployment of infrastructure alongside application code.

By integrating IaC scripts into CI/CD workflows, teams can ensure that changes to infrastructure are automatically tested, validated, and deployed alongside application changes, leading to faster and more reliable delivery of software. Most notably, developers will write Groovy scripts that are processed by the Jenkins CI/CD Pipeline.

Final Thoughts

Understanding Infrastructure as Code (IaC) can be a bit challenging at first, given that it's a relatively new concept. However, like any new skill, the best way to grasp it is by getting hands-on experience. While the Network+ Exam may require a solid understanding of IaC, it's valuable to learn about it regardless because of its widespread use in today's technology landscape.

The key thing to remember is that IaC is a way of quickly and methodically deploying hardware resources using lines of code. Hopefully, this primer has helped and brought you one step closer to your goals.

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