Argo CD is a declarative, GitOps-based continuous delivery tool for Kubernetes applications. It allows developers to automate the deployment and management of applications using a Git repository as the single source of truth.
By tracking the desired state of applications in Git, Argo CD enables consistent, reliable, and repeatable deployments across varied environments, aligning with modern DevOps practices. The tool is part of the Argo Project, which includes a suite of Kubernetes-native tools to improve development and deployment workflows.
Argo CD offers features such as automated syncing, application version control, and rollback capabilities. It simplifies Kubernetes resource management, making it easier to maintain the desired state of applications and improving collaboration among development teams.
How Argo CD Works
Argo CD continuously monitors Git repositories for changes to the desired state of Kubernetes applications. When it detects a change, it compares the live state in the cluster with the desired state defined in the Git repository. This comparison results in one of two states: synced (the live and desired states match) or out of sync (they differ).
If applications are out of sync, Argo CD can automatically or manually sync them to bring the live state back in line with the desired configuration. During syncing, Argo CD uses Kubernetes manifests (YAML or JSON), which can be plain files or templated through tools like Helm, Kustomize, or Jsonnet.
Argo CD supports multiple deployment strategies, including automated rollouts and manual approvals. It provides role-based access control (RBAC), audit trails, and health status tracking for individual Kubernetes resources. All actions and states can be viewed through a web UI, CLI, or REST API. By decoupling deployment logic from infrastructure configuration, Argo CD helps implement GitOps workflows.
5 Reasons to Use Argo CD for Your Cloud Native Applications
Here are some of the main advantages of using Argo CD to manage cloud native applications.
Declarative Configuration Management
Argo CD treats Git repositories as the single source of truth for application configurations. Teams define the desired state of their applications in declarative YAML or JSON files, which are stored in version-controlled repositories. This makes application state predictable, auditable, and easy to replicate across environments.
Because all changes flow through Git, configuration drift is eliminated. Rollbacks are straightforward—reverting to a previous application state only requires checking out an earlier commit and syncing. Declarative management also promotes collaboration and transparency: teams can propose changes through pull requests, enabling peer review and change tracking.
Automated Synchronization and Deployment
Argo CD continuously monitors Git repositories for changes and can automatically apply updates to Kubernetes clusters. When a difference is detected between the live and desired state, Argo CD syncs the application based on defined policies. These policies can be set to auto-sync, manual approval, or combinations like auto-sync with required approvals for sensitive resources.
Deployment hooks enable workflows by executing pre-sync, sync, and post-sync operations—such as database schema updates, validation scripts, or traffic shifting. With built-in retry logic and error reporting, Argo CD reduces deployment risks and ensures repeatable application delivery with minimal manual intervention.
Enhanced Visibility and Control
Argo CD offers a web UI, CLI, and REST API to observe and manage application lifecycles. Users can track sync status, view application topology, inspect individual Kubernetes resources, and monitor health conditions in real time.
Control features include fine-grained RBAC, SSO integration (e.g., via OAuth2, LDAP, or SAML), and detailed audit trails. Actions such as syncs, rollbacks, and user interactions are logged, enabling compliance and security teams to trace changes accurately.
Multi-Cluster and Multi-Tenancy Support
Argo CD supports managing applications across multiple Kubernetes clusters from a centralized interface. This is essential for enterprises running separate clusters for development, testing, staging, and production. Each cluster can be configured with its own access credentials and namespaces, and Argo CD handles deployments across them without requiring extra tooling.
Multi-tenancy is achieved through Projects—logical boundaries that isolate applications, repositories, and cluster access. Teams can operate independently within their project scope, while administrators retain oversight and governance.
Integration with Existing Toolchains
Argo CD integrates with common templating tools like Helm, Kustomize, Jsonnet, and plain manifests, allowing teams to adopt GitOps without rewriting configurations. It also supports application definitions using custom plugins, providing flexibility to extend deployment logic as needed.
In CI/CD pipelines, Argo CD can be triggered using its CLI or REST API, enabling integration with Jenkins, GitHub Actions, GitLab CI, and others. It can also work alongside tools like Prometheus for monitoring or Vault for secrets management.
Best Practices for Using Argo CD in Cloud Native Application Development
When working with Argo CD in cloud native applications, it is useful to consider the following best practices.
1. Structure Git Repositories Clearly
Organize Git repositories to match the application’s architecture, deployment environments, and team ownership. A clear structure improves maintainability and helps enforce deployment boundaries. Common patterns include:
- Mono-repo: All applications and environments in one repository. Easier for centralized management, but requires clear folder structure and access control.
- Multi-repo: Each application or environment in a separate repo. Enables decentralized ownership and tighter permissions.
The “app of apps” pattern is useful for managing many applications—define a root Argo CD application that references child applications, each pointing to their own configurations. Separate configurations by environment using folders (e.g., dev/, prod/) or branches, and avoid mixing them to reduce the risk of deploying incorrect settings.
Use tools like Kustomize overlays or Helm values to share base configurations while customizing per environment. Keep commits small and focused to make code reviews and change tracking easier.
2. Configure Automated Synchronization Judiciously
Auto-sync should be configured carefully to match the risk profile of each environment. For non-production environments, enabling auto-sync with retries speeds up feedback loops and supports continuous delivery. For production or critical apps, consider requiring manual approvals or limiting auto-sync to non-sensitive resources.
Use sync waves to control the order of resource deployment—for example, ensuring persistent volumes or custom resource definitions are applied before dependent workloads. Sync hooks (pre-sync, sync, post-sync) allow developers to run custom logic during deployments, such as validating configurations, applying database migrations, or shifting traffic.
Make sync policy part of the Git-managed application configuration, and monitor sync outcomes to detect drift or failures early. Combine with observability tools to alert on failed syncs or unexpected state changes.
3. Leverage Namespaces and RBAC
Namespaces provide logical isolation in Kubernetes and should be used to separate applications, environments, or team domains. Assign each Argo CD application to a specific namespace to avoid resource overlap and simplify access control.
Use Argo CD’s RBAC policies to define who can view, edit, or sync applications. For example, give developers read-only access in production but full control in dev environments. Argo CD integrates with SSO providers (LDAP, OAuth2, SAML), enabling centralized authentication and role mapping.
Store RBAC configurations as code and version them alongside applications to support consistent policy enforcement and easier auditing. Periodically review access permissions to ensure they align with current team roles and responsibilities.
4. Handle Secrets Securely
Do not store plaintext secrets in Git. Instead, integrate Argo CD with secret management tools that inject secrets at runtime. Options include:
- Sealed Secrets: Encrypt secrets and store them in Git; decrypted by a controller at deployment.
- External Secrets Operator: Syncs secrets from external stores like AWS Secrets Manager or Vault.
- Sops + Kustomize: Encrypt individual secret files with GPG or KMS and decrypt during rendering.
Use these tools to manage secret rotation, expiration, and access policies centrally. In Kubernetes, restrict secret access using RBAC and keep secrets in dedicated namespaces. Regularly audit cluster secrets and avoid exposing them in logs or error messages. Integrate secret scanning into CI pipelines to catch accidental leaks.
5. Optimize Deployment Strategies
Select deployment strategies based on the application’s criticality and tolerance for change. Argo CD supports progressive delivery methods such as:
- Blue-green: Deploy to a parallel environment and switch traffic once validated.
- Canary: Roll out changes incrementally, monitoring for issues before full rollout.
These patterns reduce risk and enable controlled rollbacks. Use sync hooks to run pre-deployment tests, apply schema changes, or perform smoke tests. Post-sync hooks can verify service health or send deployment notifications.
Define health checks for resources like deployments, services, and jobs. Argo CD uses these to determine application health and block further syncs if failures are detected. Combine with Git tags or commit SHAs to track exact versions deployed across environments. Automate rollback on failure by defining conditions in the sync strategy or by scripting it through the API.
By Gilad David Maayan