IaC in Kubernetes: 6 Tools, Tutorial and Tips for Success

What Is Infrastructure as Code (IaC)?

Infrastructure as code (IaC) manages and provisions computing infrastructure through machine-readable scripts, rather than physical hardware configuration or interactive tools. IaC uses code or configuration files to automate the setup, management, and teardown of infrastructure, making it scalable and repeatable. This approach is integral to DevOps practices, enabling rapid deployment and consistent environment creation.

IaC reduces human error, offers version control, and ensures that infrastructure is consistent across environments. It allows teams to manage complex infrastructure more efficiently, making development, staging, and production environments similar from a configuration standpoint. This consistency eases troubleshooting and reduces discrepancies between different environments.

Kubernetes provides an environment that is inherently supportive of the IaC approach. Even the simplest Kubernetes deployment uses a YAML manifest, which is essentially infrastructure as code. However, there are several tools and techniques you can use to make more sophisticated use of IaC in Kubernetes, taking infrastructure management to the next level.

Benefits of IaC in the Kubernetes Environment

Tracking and Auditability

One major benefit of IaC in Kubernetes is enhanced tracking and auditability. Every change in the configuration can be traced back to specific commits, providing a clear history of modifications. This ensures that you can audit who made changes, what was altered, and when it happened. This accountability is crucial for security and compliance, especially in highly regulated industries.

Version control systems can track infrastructure changes alongside application code, facilitating a unified change management process. This synchronization ensures that infrastructure changes can be reviewed, tested, and rolled back if necessary, bolstering the overall reliability and security of the system.

Reusability

IaC enables significant reusability of infrastructure patterns. By encapsulating infrastructure setup in code, these configurations can be reused across projects and teams, reducing duplication of effort. Templates and modules can be shared and adapted to fit various needs without starting from scratch, increasing productivity and ensuring consistency.

Reusability also drives standardization across environments. Standard modules can serve as a base upon which additional, specific configurations can be layered, maintaining uniformity while allowing flexibility for project-specific adjustments.

Consistency

IaC ensures consistency across different environments by using the same configuration files to deploy infrastructure. This eliminates discrepancies often found when environments are manually configured. Consistent environments simplify debugging and reduce the risk of environment-specific issues, leading to more reliable deployments.

Automated scripts help dismantle the “it works on my machine” problem by standardizing the setup process. When environments are identical, developers and operations teams can confidently replicate bugs and fixes across all stages of the deployment pipeline.

Popular IaC Tools for Kubernetes

1. Helm

Helm is a package manager for Kubernetes that simplifies the deployment and management of applications. It allows you to define, install, and upgrade even the most complex Kubernetes applications using charts—pre-configured Kubernetes resources that can be easily shared and reused. Helm charts package up Kubernetes manifests into a single, deployable unit, making it easier to deploy consistent configurations across different environments.

Helm’s templating system provides a way to manage environment-specific values, allowing you to deploy the same application with different configurations. This approach not only reduces the risk of configuration drift but also enables teams to manage dependencies and roll back changes easily if necessary. Helm is particularly useful for deploying microservices and other complex applications where multiple Kubernetes resources need to be managed together.

2. Terraform

Terraform is a popular IaC tool that is cloud-agnostic, allowing you to define and provision infrastructure across multiple cloud providers and on-premises environments. In the context of Kubernetes, Terraform can be used to automate the provisioning of Kubernetes clusters, as well as manage the underlying cloud resources like virtual machines, networking, and storage.

With Terraform, infrastructure is defined in declarative configuration files that describe the desired state. Terraform then uses these files to generate an execution plan, which it follows to achieve that state. Terraform’s state management allows for tracking infrastructure changes over time, making it easy to update and scale your Kubernetes infrastructure consistently. Additionally, its robust module system encourages reusability, making it easier to manage large-scale Kubernetes deployments.

3. Pulumi

Pulumi is an IaC tool that allows you to define infrastructure using familiar programming languages like Python, JavaScript, TypeScript, Go, and C#. Unlike traditional IaC tools that rely on domain-specific languages, Pulumi integrates with your existing software development practices, enabling you to use the same languages, tools, and workflows to manage both application code and infrastructure.

Pulumi’s Kubernetes support allows you to manage not only the Kubernetes resources but also the infrastructure that Kubernetes runs on. This unified approach can simplify the process of deploying and scaling Kubernetes clusters, especially in multi-cloud or hybrid environments. Pulumi also provides strong integration with CI/CD pipelines, allowing you to automate the entire infrastructure lifecycle.

4. Kustomize

Kustomize is a native Kubernetes tool that provides a way to customize Kubernetes YAML configurations without modifying the original files. It allows you to define a base configuration and then overlay changes to adapt the configuration for different environments, such as development, staging, and production.
Kustomize is particularly useful when you need to maintain multiple variants of Kubernetes resources. By managing overlays, you can ensure that each environment adheres to the same base configuration while allowing for specific customizations. Kustomize integrates seamlessly with kubectl, making it easy to apply customized configurations directly to your Kubernetes clusters.

5. Crossplane

Crossplane extends Kubernetes to manage cloud infrastructure through Kubernetes-native declarative APIs. It treats cloud resources like databases, networks, and storage as custom resources within Kubernetes, allowing you to manage both application workloads and infrastructure using a single control plane.

Crossplane enables you to define and manage infrastructure through Kubernetes manifests, just like you would with any other Kubernetes resource. This approach brings the benefits of Kubernetes’ declarative model to infrastructure management, providing a consistent and scalable way to manage resources across multiple cloud providers. Additionally, Crossplane’s composability allows teams to define infrastructure abstractions that fit their specific needs, enabling higher-level, reusable infrastructure patterns.

6. Ansible

Ansible is an automation tool that uses a simple, agentless architecture to manage infrastructure. In Kubernetes environments, Ansible is often used to automate tasks like provisioning clusters, deploying applications, and managing configurations. Ansible’s playbooks, written in YAML, describe the desired state of the infrastructure, making it easy to apply consistent configurations across different environments.

Ansible integrates well with Kubernetes through modules that allow you to manage Kubernetes resources directly. It is particularly useful in hybrid environments where Kubernetes needs to be integrated with other systems, as Ansible can manage a wide range of infrastructure components beyond just Kubernetes. Its flexibility and ease of use make it a popular choice for automating complex workflows in Kubernetes environments.

Tutorial: Hands-On Kubernetes IaC with Kustomize

In this tutorial, we will explore how to use Kustomize to manage Kubernetes resources efficiently. Kustomize offers a declarative way to customize Kubernetes configurations, allowing developers to maintain consistency across environments while adapting to different needs. The instructions are adapted from the Kubernetes documentation.

Generating Resources

Kustomize allows you to generate Kubernetes resources without manually creating YAML files for every object. You can specify configurations for common resource types like ConfigMaps and Secrets directly in the kustomization.yaml file, which Kustomize then uses to generate the required Kubernetes objects. This is done by defining the configMapGenerator and secretGenerator fields.

For example, to generate a ConfigMap, you would add the following to your kustomization.yaml:

configMapGenerator:
  - name: example-config
    literals:
      - key1=value1
      - key2=value2

This configuration tells Kustomize to generate a ConfigMap with the specified key-value pairs. Similarly, Secrets can be generated with the secretGenerator field, making it easy to manage sensitive data without directly embedding it into your YAML files.

Kustomize also allows you to customize existing resources with transformers and patches, providing flexibility when scaling and deploying applications across multiple environments.

Setting Cross-Cutting Fields

Kustomize supports setting cross-cutting fields—common settings that need to be applied across multiple resources—without editing each resource file manually. This is useful for fields like labels and annotations that should be consistent across all resources.You can achieve this by using the commonLabels and commonAnnotations fields in your kustomization.yaml. For example:

commonLabels:
  app: my-app
  environment: staging

This configuration will automatically apply the specified labels to all resources managed by Kustomize, ensuring that these labels are consistent throughout your environment. You can also set annotations in a similar way using the commonAnnotations field.

This approach is especially useful when managing large deployments with many resources, as it reduces duplication and ensures consistency without manual effort.

Composing and Customizing Resources

Kustomize makes it easy to compose and customize Kubernetes resources by managing them in the same file or directory, or by combining resources from multiple files. The resources field in the kustomization.yaml file specifies a list of configuration files to be included. This allows you to manage various Kubernetes objects, like Deployments and Services, in a unified manner.

For example, to compose a simple NGINX application, you can define the Deployment and Service resources in separate YAML files and include them in the kustomization.yaml:

# deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app
spec:
  replicas: 2
  selector:
    matchLabels:
      app: my-app
  template:
    metadata:
      labels:
        app: my-app
    spec:
      containers:
      - name: app
        image: nginx
        ports:
        - containerPort: 80

Here is the code for kustomization.yaml:

# kustomization.yaml
apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization

# Add the resources you want to include
resources:
  - deployment.yaml

This defines a Deployment with 2 replicas of an NGINX container labeled app: my-app.

# service.yaml
apiVersion: v1
kind: Service
metadata:
  name: my-app
spec:
  selector:
    app: my-app
  ports:
  - protocol: TCP
    port: 80

This service will now target pods labeled with app: my-app and expose port 80.

Best Practices for IaC in Kubernetes

1. Version Control for Kubernetes Manifests

Version control is critical for managing Kubernetes manifests. Use systems like Git to track changes to your YAML files, providing an audit trail and facilitating collaboration among team members. This practice helps maintain a clear history of modifications, enhancing transparency and accountability.

Branching strategies can be employed to manage changes across different environments, such as development, staging, and production. This structure ensures that changes can be tested and reviewed before being deployed to live environments, increasing stability and reliability.

2. Environment Segmentation

Environment segmentation involves creating distinct infrastructure for different stages of development, such as development, staging, and production. Each environment should be isolated to prevent changes in one from affecting the others. This segmentation is essential for testing and validation processes, ensuring that new features and updates do not disrupt production services.

Automating the provisioning of these environments using IaC ensures consistency and allows for rapid setup and teardown. Environment segmentation also helps in managing resource allocation and cost, as development and testing environments can be scaled down during off-peak times.

3. Modularize Your IaC Code

Modularizing IaC code involves breaking down large, complex configurations into smaller, reusable modules. This practice enhances the manageability and scalability of infrastructure code. Modules can be shared across projects, reducing redundancy and improving efficiency.

Modularization also improves readability and maintainability, making it easier for teams to understand and modify specific parts of the infrastructure without affecting the entire setup. This approach aligns with best practices in software development, promoting cleaner and more maintainable codebases.

4. Implement Drift Detection and Reconciliation

Drift detection involves identifying discrepancies between the declared IaC configurations and the actual deployed infrastructure. Implementing tools and practices to detect and reconcile drift ensures that infrastructure remains consistent with the specified configurations. This process is crucial for maintaining the integrity and reliability of deployed systems.

Automated reconciliation can correct detected drift, reverting infrastructure to its intended state. This not only ensures consistency but also enhances security by preventing unauthorized changes. Regular drift detection audits are vital to maintaining an up-to-date and secure infrastructure.

5. Use GitOps for Continuous Delivery

GitOps involves using Git repositories as the source of truth for declarative infrastructure and applications. This practice integrates well with IaC, as configurations stored in version control are automatically applied to Kubernetes clusters. GitOps enhances continuous delivery by ensuring that changes are systematically tracked, reviewed, and deployed.

Using GitOps, infrastructure and application deployments are automated and consistent, significantly reducing manual intervention and errors. This approach promotes a robust continuous deployment pipeline, where infrastructure and applications evolve together seamlessly.

Infrastructure as Code with Codefresh CI/CD

Codefresh is built for modern tools with support for flexible frameworks. Most infrastructure as code tools are available as docker images and can be seamlessly integrated into Codefresh pipelines – this happens to be a very common pattern for many of our customers. Learn more about how you can easily execute a custom freestyle step with any of these images here.
If you are interested in managing Codefresh resources with Terraform, we also have you covered there! The Codefresh Terraform provider can manage the creation, updates, and removal of Codefresh resources allowing you to utilize your current infrastructure as code workflows without compromises.