A Beginner's Guide to Infrastructure as Code: How IaC Works, Its Benefits, and Common Challenges

This is an article from DZone's 2023 DevOps Trend Report.

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Infrastructure as Code (IaC) is the practice of provisioning and managing infrastructure using code and software development techniques. The main idea behind IaC is to eliminate the need for manual infrastructure provisioning and configuration of resources such as servers, load balancers, or databases with every deployment. As infrastructure is now an integral part of the overall software development process and is becoming more tightly coupled with application delivery, it's important that we make it easier to deliver infrastructure changes. 

Using code to define and manage infrastructure and its configuration enables you to employ techniques like version control, testing, and automated deployments. This makes it easier to prevent all sorts of application issues, from performance bottlenecks to functionality failures. 

This article will explain how IaC works, highlighting both approaches, as well as the benefits and challenges of delivering infrastructure as code within a DevOps environment.

How Does IaC Work?

Historically, infrastructure management was mostly a manual process done by specialized system administrators. You needed to manually create virtual machines (VMs), manage their software updates, and configure their settings. This became highly expensive and time-consuming, especially with the rapid pace of modern software development. 

IaC evolved as a solution for scalable infrastructure management. It allows you to codify the infrastructure to then be able to create standardized, reusable, and sharable configurations. IaC also allows you to define infrastructure configurations in the form of a code file. For example, Figure 1 demonstrates how you’d define the creation of an S3 bucket in AWS, using CloudFormation. 

Resources:
  S3Bucket:
    Type: 'AWS::S3::BUCKET'
    DeletionPolicy: Retain
    Properties:
BucketName: DOC-EXAMPLE-BUCKET

As you define your Infrastructure as Code, you can implement the same practices that you use with application development code, like versioning, code review, and automated tests. 

Figure 1: The IaC workflow

To implement IaC, you can use a variety of tools and technologies, like: 

• Configuration management tools that make sure the infrastructure is in the desired state that you previously defined, like Ansible, Chef, or Puppet.
• Provisioning tools (e.g., CloudFormation templates) that allow you to define cloud resources in the form of a JSON or YAML file, and provision that infrastructure on a cloud platform.
• Containerization tools (e.g., Docker, Kubernetes) used to package applications and their dependencies into containers that can be run on any infrastructure.

Approaches to IaC

There are two different Infrastructure as Code approaches: imperative (procedural) IaC and declarative (functional) IaC. 

With the imperative method, the developer specifies the exact steps that the IaC needs to follow to create the configuration. The user commands the automation completely, which makes this method convenient for more specific use cases where full control is needed.

The main advantage of the imperative method is that it allows you to automate almost every detail of the infrastructure configuration. This also means that you need a higher level of expertise to implement this type of automation as it's mostly done by executing scripts directly on the system.

Here is an example of an imperative way to create an S3 bucket using the AWS CLI: 

aws s3api create-bucket --bucket my-new-bucket --region eu-central-1

When you run this command, the AWS CLI will create a new Amazon S3 bucket with the name my-new-bucket in the eucentral-1 region. 

With the declarative method, the developer specifies the desired outcome without providing the exact steps needed to achieve that state. The user describes how they want the infrastructure to look through a declarative language like JSON or YAML. This method helps with standardization, change management, and cloud delivery. Features can be released faster and with a significantly decreased risk of human error. 

Here's a simple example of a declarative Infrastructure as Code using AWS CloudFormation:

{
“Resources”: {
“EC2Instance”: {
“Type”: “AWS::EC2::Instance”,
“Properties”: {
“InstanceType”: “t2.micro”,
“ImageId”: “ami-0c94855bac71e”,
“KeyName”: “my-key”
                    }
              }
}
}

This script tells CloudFormation to create an EC2 instance of type t2.micro, and the CloudFormation will take care of all the required steps to achieve that state with the specific properties you defined.

Figure 2: Overview of IaC approaches 

The Benefits and Challenges of IaC

Infrastructure as Code is one of the key practices in DevOps and provides many benefits that save time and money, as well as reduce risk. But as with any tool, solution, or practice that you adopt in the organization, it is important to weigh the challenges that one may face when implementing IaC methods. 

Table 1: IaC benefits vs. challenges — factors to consider

Conclusion

With IaC, systems can be easily reproduced and reused; the processes are consistent. As DevOps culture becomes more pervasive, maintaining a strategic advantage through IaC will likely become an increasingly important goal. If you work at an organization that aims to implement Infrastructure as Code within their existing processes, it can be helpful to understand the benefits and challenges that your team might encounter. The trick is to walk a fine line between understanding your business' infrastructure needs and recognizing the potential for improvement that IaC offers. 

To ensure that IaC is implemented properly, it's important to start small. You want to gradually increase the complexity of the tasks, avoid over-complicating the codebase, continuously monitor the IaC implementation to identify areas for improvement and optimization, and continue to educate yourself about the different tools, frameworks, and best practices in IaC. 

Check out these additional resources to continue learning about IaC: 

• Getting Started With IaC, DZone Refcard
• IaC Security: Core DevOps Practices to Secure Your Infrastructure as Code, DZone Refcard
• "Infrastructure-as-Code: 6 Best Practices for Securing Applications" by Jim Armstrong
• "5 Best Practices for Infrastructure as Code" by Marija Naumovska
• "Best Infrastructure as Code Tools (IaC): The Top 11 for 2023" by Florian Pialoux 

This is an article from DZone's 2023 DevOps Trend Report.

For more:

Read the Report