Declarative vs. Imperative Programming for Infrastructure as Code (IaC)

Infrastructure as Code, or IaC, is a DevOps practice that involves turning your infrastructure configurations into software scripts. This allows you to automatically provision and patch new resources, which saves time and leads to fewer configuration mistakes. IaC tools use either a declarative or imperative programming language to execute configuration scripts. Let’s define these two programming paradigms before comparing declarative vs imperative programming for DevOps infrastructure as code, so you can see the advantages and disadvantages of each.

What is Declarative Programming for IaC?

In declarative programming, you specify the name and properties of the infrastructure resources you wish to provision, and then the IaC tool figures out how to achieve that end result on its own. You declare to your IaC tool what you want, but not how to get there. Some examples of popular IaC tools that use the declarative programming paradigm include Terraform, Puppet, Ansible, Salt, and CloudFormation.

What is Imperative Programming for IaC?

In imperative programming, you specify a list of steps the IaC tool should follow to provision a new resource. You tell your IaC tool how to create each environment using a sequence of command imperatives. Chef is a popular imperative IaC tool, and both Ansible and Salt have some support for imperative programming as well.

Declarative vs. Imperative Programming

When you compare declarative vs imperative programming, you’ll find that each paradigm comes with advantages and disadvantages that you need to consider before choosing your approach to IaC.

Pros and Cons of Declarative Programming

Declarative programming is a popular approach to infrastructure as code. You define the desired end-state of the final configuration, and the IaC solution figures out how to get there. Declarative programming is highly idempotent, or repeatable, which means you can execute your IaC commands over and over again and still achieve the same result. The declarative paradigm also adapts well to configuration drift – the inevitable, slow changes to your infrastructure over time – because the IaC tool’s provisioning steps are not explicitly defined.

The biggest drawback of the declarative approach is that you give up a lot of control over the individual steps in the provisioning process. It’s also not the best choice for small fixes and updates that can be handled by a simple CLI (command line interface) script – declarative programming can overcomplicate matters and slow down the process.  

Pros and Cons of Imperative Programming

Imperative programming, on the other hand, requires more scripting knowledge because you must write commands for every provisioning step. This gives you control over how you accomplish infrastructure tasks, which is ideal when you need to make small changes, optimize for a specific purpose, or account for software quirks.

The biggest initial challenge to the imperative approach is that it requires a high level of skill with the programming language, which infrastructure teams in the initial stages of the DevOps journey may not yet have. Imperative IaC scripts are often less idempotent as well — your predefined steps can lead to different results depending on the environment. Plus, imperative IaC scripts are so explicit that an error with one step can cause the whole thing to fail. 

Declarative vs. Imperative Programming Comparison:

When to Use Declarative IaC

Declarative IaC is a strong choice when you want predictable, repeatable infrastructure that can be recreated reliably over time. Because you only define what the final configuration should look like, the IaC tool handles all the underlying logic. This makes declarative programming well suited for larger environments, frequent deployments, and situations where configuration drift needs to be managed automatically.

Teams also benefit from the reduced scripting overhead that comes with declarative models. Since these tools emphasize idempotency, running the same configuration multiple times produces the same outcome—an essential feature for maintaining stable environments. When the priority is consistency rather than hands-on control, declarative IaC is often the more efficient approach.

When to Use Imperative IaC

Imperative IaC is ideal when you need full control over how infrastructure is created or modified. By defining each action explicitly, you can tailor the process to fit unique requirements, software behaviors, or environment-specific constraints. This makes imperative programming particularly useful for fine-tuned changes, small updates, or one-off tasks that don’t require full orchestration.

Because imperative IaC provides step-by-step visibility, it can also simplify troubleshooting. Teams can identify where a command failed and address the issue directly. While this programming style requires more scripting knowledge, it offers the flexibility needed for highly customized or incremental infrastructure work.

Choosing the Right IaC Approach for a Streamlined DevOps Journey

Overall, many organizations striving to fully automate and orchestrate their DevOps infrastructure gravitate toward the declarative approach. Declarative IaC tools allow teams to build highly repeatable and adaptable configuration scripts without needing extensive programming experience. At the same time, teams easing into automation—or handling small, targeted updates—may find that an imperative approach offers the simplicity and control they need to get started.

Understanding the differences between declarative and imperative programming for IaC is just one step in building a strong DevOps foundation. To advance further, many teams partner with a trusted DevOps solutions company that can simplify releases, improve quality, and bring consistency to every stage of the delivery pipeline.

Copado provides a comprehensive suite of DevOps solutions that unify version control, automated deployments, quality checks, and compliance within one platform. Copado also supports broader Salesforce transformation initiatives—including Salesforce data cloud implementation—helping teams accelerate integration efforts and maintain alignment across their entire ecosystem.

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