Introduction to GitOps

GitOps is a modern approach to managing infrastructure and applications using Git as the single source of truth, integrating DevOps practices with Git to automate and control infrastructure provisioning, configuration management, and software deployments. GitOps ensures that the desired state of the infrastructure or application is stored in a Git repository, and any changes are automatically applied to the system through continuous delivery (CD) pipelines.

Key Principles of GitOps

1. Declarative Configuration:

   • The desired state of infrastructure and applications is described declaratively (e.g., in YAML files) and stored in Git repositories.

2. Version Control:

   • Every change to infrastructure or applications is version-controlled in Git, serving as the single source of truth for managing configurations, enabling rollbacks, history tracking, and easy auditing of changes.

3. Automation:

   • Changes committed to the Git repository automatically trigger automated deployment processes, typically using CI/CD pipelines or tools like ArgoCD or FluxCD.

4. Continuous Reconciliation:

   • A controller continuously monitors the system's actual state and automatically reconciles any differences with the desired state defined in Git.

How GitOps Works

1. Declare the Desired State:

   • Define the infrastructure (e.g., servers, networks, storage) and application configuration (e.g., container deployment) in a Git repository using declarative files like YAML, JSON, or HCL.

2. Make Changes via Pull Requests:

   • Changes to the infrastructure or applications are made by updating files in the Git repository, which can be reviewed and approved through pull requests for collaboration and oversight.

3. Automated Deployment:

   • Once changes are committed to Git, an automated pipeline (CI/CD) is triggered to apply the changes to the actual infrastructure or applications.

4. Reconciliation & Monitoring:

   • The GitOps controller (e.g., ArgoCD, Flux) constantly checks the live environment against the desired state in Git and automatically corrects any differences to maintain alignment.

Benefits of GitOps

• Consistency & Repeatability: Since everything is stored in Git, you get consistent deployments and infrastructure management.

• Enhanced Security: Git acts as an auditable, version-controlled source, making it easier to track changes, roll back mistakes, and avoid unauthorized changes.

• Faster Recovery: With Git’s versioning capabilities, you can easily roll back infrastructure or application changes to a previous stable state.

• Collaboration & Transparency: Teams can collaborate on infrastructure changes in the same way they collaborate on code changes, enhancing transparency and peer reviews.

• Increased Developer Productivity: Developers can manage infrastructure changes with the same Git-based workflows they are used to for code development.

Common Tools for GitOps

• ArgoCD: A popular tool for continuous delivery and GitOps workflows, often used in Kubernetes environments.

• FluxCD: Another tool that automatically ensures that the state in the Git repository matches the actual state in the system.

• Jenkins X: Provides automated CI/CD pipelines with a GitOps approach, often used in Kubernetes environments.

GitOps in Action

For instance, in a Kubernetes environment, a GitOps workflow might look like this:

• All Kubernetes manifests (for services, deployments, config maps, etc.) are stored in a Git repository.

• A developer makes a change to the application deployment configuration (e.g., scaling replicas) by editing the YAML manifest in the Git repository.

• The changes trigger a CI/CD pipeline, which updates the Kubernetes cluster with the new configuration.

• A controller like ArgoCD continuously monitors the cluster to ensure it matches the desired configuration in Git, reverting any manual changes in the cluster to match the desired state in Git.

In summary, GitOps is a DevOps evolution that brings infrastructure automation and operational management under the control of Git, improving transparency, reliability, and automation.