Infrastructure as Code: Everything You Need to Know

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Infrastructure is one of the core principles of the software development process - it is directly responsible for the stable operation of software applications. This Infrastructure can range from servers, load balancers, firewalls, and databases to complex container clusters.

Considerations for the Infrastructure should apply not only to production environments, as they span the entire development process, but also to tools and platforms, such as CI/CD platforms, appearance environments, and testing tools. As the complexity of software products increases, the consideration of these infrastructures has to change as well. The traditional approach of manually managing Infrastructure to meet the demands of DevOps' modern and rapid software development cycles quickly becomes an unscalable solution. This is why IaC has become the de facto solution in development today.

What is Infrastructure as Code?

IaC, Infrastructure as Code, is the supply and management process of Infrastructure defined by code instead of manually. IaC takes most of the resource provisioning work away from the developer, who can execute scripts to prepare the Infrastructure. This way, application deployment is not hampered by waiting for Infrastructure, and system administrators do not have to manage time-consuming manual processes.

The following is a step description of how creating an IaC environment works：

• Developers define configuration parameters in a Domain-Specific Language (DSL).

• Instruction files are sent to the controller server, management API, or code repository.

• The IaC platform creates and configures the Infrastructure according to the developer's instructions.

By treating the Infrastructure as code, users do not have to configure the environment every time they develop, test, or deploy software. All infrastructure parameters are saved in a file called an inventory.

Like all code files, inventories are easy to reuse, edit, copy, and share making it faster and more consistent to build, test, prepare, and deploy your Infrastructure.

The developer encodes the configuration file and stores it in version control. If someone edits a file, then the pull request and code review workflow can check the correctness of the changes.

IaC Best Practices

Implementing infrastructure automation will require many changes and refactoring, which can be arduous for organizations. If you want to avoid most limitations and make the transition as smooth as possible, please follow these best practices!

1. Using CI/CD and Quality Control in IaC's Repository

This will help you maintain the excellent quality of your code and get a quick feedback loop (after application changes) from your DevOps team or developers. Fortunately, testing frameworks like Terratest for Terraform allow us to write actual tests. The sooner you try to cover everything with it, the more you will benefit from it, and the fewer unexpected problems will occur with the Infrastructure. To be sure, it's not possible to predict application errors here, but at least you can have more confidence in your Infrastructure.

2. Making your Infrastructure Modular Code

Microservices architecture is a popular trend in software development that builds software by developing smaller, modular units of code that can be deployed independently of other product components.

The same concept applies to IaC. The Infrastructure can be broken down into individual modules or stacks and combined in an automated manner.

This method has the following advantages:

• First, the microservices architecture allows flexible access control to various infrastructure code parts. For example, junior engineers may not be familiar with or have expertise in certain parts of the infrastructure configuration. By modularizing the infrastructure code, it is possible to deny junior engineers access to those components until they can keep up.

• In addition, a modular infrastructure naturally limits the number of changes that can be made to the configuration. More minor changes make bugs easier to detect and make your team more flexible. If IaC is used to support a microservice architecture, then configuration templates should be used to ensure consistency as the infrastructure scales to large server clusters. This will ultimately be valuable for configuring servers and specifying how they should interact.

3. Continuous Testing, Integration, and Deployment

A continuous testing, integration, and deployment process is an excellent way to manage all possible changes that may be made to your infrastructure code.

Testing should be applied strictly to your infrastructure configuration to ensure no post-deployment issues. Depending on your needs, you should perform a series of tests. You can set up automatic tests to run each time you change the configuration code.

Infrastructure security should also be continuously monitored and tested. DevSecOps is an emerging practice. Security professionals work with developers to constantly integrate threat detection and security testing throughout the software development life cycle instead of just investing at the end. By increasing collaboration between testing, security, and development teams, bugs and threats can be identified early in the development life cycle so that they can be minimized at go-live.

These configuration templates can be used multiple times in different environments, such as development, testing, and quality assurance through an excellent continuous integration process. Developers can then use a consistent infrastructure configuration in these environments. This constant integration will reduce the risk of errors that can be harmful to the application when deploying the infrastructure into the production environment.

4. Maintaining Version Control

The configuration file will be subject to version control. Because all configuration details are written in code, any changes to the codebase can be managed, tracked, and coordinated.

As with application code, source code control tools such as Git, Mercurial, and Subversion should be used to maintain the version of the IaC codebase. This provides an audit trail for code changes and allows for collaboration, peer review, and testing of IaC code before it goes live.

The best practice of code branching and merging should also be used to further increase developer collaboration and ensure that updates to IaC code are properly managed.

If you're starting to use IaC, don't try to automate everything from the beginning. The reason for this is the rapid pace of change. Once your platform becomes more or less stable, you will be able to automate its resource provisioning and maintenance.

Challenges of IaC

IAC has many benefits, but the model does have some challenges that need to be solved that can be understood and adequately solved before the implementation process.

1. Configuration Drift

No matter how consistent or how often you configure the server, configuration drift may occur in the long run. This is why it is necessary to ensure no external disturbances after establishing the IaC workflow. You must ensure that you follow the pre-established maintenance workflow when you need to modify the infrastructure. This principle is called infrastructure invariance - that is, the infrastructure should operate precisely in a specified way, and if changes are required, an entirely new set of infrastructure is provided, and the obsolete infrastructure is wholly replaced.

If you still make inconsistent changes to similar system groups, some of these changes will inevitably differ from others, which may lead to configuration changes.

2. Potential Repetition of Errors

Although the implementation process and machine creation of IaC rely heavily on automation, certain parts of the entire process still need to be done manually. Writing the father code is one of those processes, and there is always the potential for error when manual work is involved. Even in an environment where regular and consistent QA checks, people can make mistakes or overlook critical things.

As a side effect of automation, these errors may occur on multiple machines and cause as many security vulnerabilities as possible. So, keep in mind that almost all cloud vulnerabilities come from misconfiguration. It is recommended to carefully examine the code that generates the IaC architecture to ensure security from beginning to end, which can be achieved through rigorous and highly consistent testing and a thorough review process. Of course, these different processes often come with a corresponding increase in expense.

For organizations seeking automation and faster delivery, infrastructure as code is slowly but surely becoming the normal state. Only through simplified workflow and improved development environment can applications be developed faster.