Top 2 CI/CD Tools and Kubernetes: Jenkins and ArgoCD

Continuous Integration (CI) and Continuous Deployment (CD) are essential practices in modern DevOps, ensuring faster and more reliable software delivery by automating code testing, building, and deployment.

At Retesys, we have extensive experience in cloud software architecture, development, and DevOps solutions that integrate CI/CD pipelines with Kubernetes.

This guide presents a list of questions to help you decide which of the two most popular CI/CD tools best suits your project.

What is your current level of Kubernetes adoption?

• If you are fully invested in Kubernetes:

  Argo CD is the more natural choice. As a Kubernetes-native tool, Argo CD integrates directly with Kubernetes, providing a streamlined workflow for managing Kubernetes applications using declarative GitOps practices. It simplifies the synchronization and deployment of Kubernetes resources.

• If you are partially using or plan to gradually adopt Kubernetes:

  Jenkins pipelines might offer more flexibility. Jenkins supports both Kubernetes and non-Kubernetes environments, making it easier to transition from traditional infrastructure to containerized solutions over time.

What kinds of applications are primarily used in your organization?

• If your focus is on mobile or desktop apps, with an emphasis on Continuous Integration (CI) features:

  Jenkins pipelines might be a better fit. Jenkins has been a longstanding, reliable tool for Continuous Integration (CI), offering a robust ecosystem of plugins that support various build, test, and integration tasks. It is versatile and widely adopted for CI tasks across different platforms.

• If your focus is on backend or web apps, with an emphasis on Continuous Deployment (CD) functionality:

  Following GitOps practices would be beneficial. Argo CD is specifically designed for Continuous Deployment (CD) using GitOps principles, making it an excellent choice for Kubernetes-native deployments. It seamlessly manages application states in Kubernetes clusters based on Git repository updates.

How complex are your deployment needs (e.g., multi-cloud, multi-cluster)?

• For complex, multi-cloud, or multi-cluster environments:

  Argo CD offers native support for managing multiple clusters, making it suitable for organizations needing to manage deployments across different environments consistently. Its GitOps model provides clear, version-controlled deployment states, reducing configuration drift.

• For simpler, single-cloud environments:

  Jenkins pipelines, especially when integrated with Kubernetes, can efficiently handle deployments without the overhead of multi-cluster management. Jenkins' flexibility with plugins allows it to be tailored to various deployment environments, from simple to moderately complex scenarios.

What is your team's expertise with Kubernetes and GitOps?

• If your team has strong Kubernetes and GitOps expertise:

  Argo CD will align well with their skills. The tool’s GitOps-focused deployment model requires a good understanding of Kubernetes and Git workflows, making it ideal for teams already proficient in these areas.

• If your team has a more general DevOps background:

  Jenkins pipelines might be more familiar and easier to adopt. Jenkins has a larger community and extensive documentation, making it accessible for teams new to Kubernetes. Its UI and pipeline-as-code approach can bridge the gap for teams gradually learning Kubernetes.

What are your security and compliance requirements?

• For high security and compliance requirements:

  Argo CD's integration with Kubernetes RBAC and support for Single Sign-On (SSO) via LDAP, SAML, or OIDC provides robust security features. Its GitOps model ensures that deployment changes are version-controlled and traceable, aiding in compliance efforts.

• If you need extensive plugin-based security integration:

  Jenkins, with its large ecosystem, offers many security plugins to integrate with tools like HashiCorp Vault for secrets management, providing flexibility in how security is handled across different environments.

Learn how to secure your CI/CD pipelines by applying Kubernetes Security Best Practices.

What is your approach to managing infrastructure as code (IaC)?

• If you use or plan to use GitOps for IaC:

  Argo CD is specifically built around GitOps, making it a natural choice for managing infrastructure as code. It allows teams to define their Kubernetes deployments declaratively in Git repositories and automatically synchronize cluster states with those repositories.

• If you prefer a more traditional approach to IaC:

  Jenkins pipelines, along with tools like Terraform and Ansible, can be integrated into Jenkins jobs, providing a more conventional way to manage infrastructure. This flexibility is helpful if your team is accustomed to a broad range of IaC tools.

What is your organization's preference for tool complexity and maintenance?

• If minimizing maintenance and configuration complexity is a priority:

  Argo CD, with its declarative approach and Kubernetes-native design, might be easier to manage and maintain, especially for organizations already using Kubernetes extensively.

• If your team is comfortable managing complex configurations:

  Jenkins pipelines offer extensive customization options through scripting and plugins, which can lead to complexity. Jenkins supports a declarative configuration approach through the Configuration as Code (CasC) plugin, allowing administrators to define Jenkins system settings, jobs, credentials, and plugins using YAML files.

What is your budget for CI/CD tools?

• If budget constraints are tight:

  Both Jenkins and Argo CD are open-source and free to use, but Jenkins might incur additional costs for the development of custom integrations, especially when integrating with Kubernetes environments. Setting up Jenkins to build, test, and deploy to Kubernetes involves numerous plugins, custom scripts, and YAML configurations, which can lead to maintenance challenges. Jenkins may also require more substantial infrastructure investments due to its typically higher resource usage.

• If cost-effectiveness with scalable, Kubernetes-native solutions is desired:

  Argo CD might be more cost-effective as it leverages Kubernetes’ scaling capabilities and has lower overhead in Kubernetes-native environments. Argo CD is mostly stateless and relies on the Kubernetes cluster, with all data persisted as Kubernetes objects.

Conclusion and Recommendations

Both Jenkins pipelines and Argo CD offer robust solutions for CI/CD, but the best choice depends on your organization's specific needs, current infrastructure, and future goals.

Jenkins pipelines are ideal for companies requiring a flexible CI tool capable of handling a wide range of environments, including both traditional and containerized infrastructure. Jenkins excels in complex CI workflows, particularly where multiple parallel builds and extensive plugin support are needed.

Argo CD, on the other hand, is best suited for organizations fully invested in Kubernetes, looking to streamline continuous deployment with GitOps practices. Its Kubernetes-native design ensures scalability, high availability, and a straightforward management approach for cloud-native applications.

Note 1: As a Swiss army knife in CI/CD for many years, Jenkins has become very flexible, offering different ways of configuring its pipelines. At Retesys, we prefer using modern declarative approaches, which encourage storing all pipeline configurations and scripts in source control repositories. In Jenkins, this can be achieved by using declarative pipelines, which don't implement logic directly but rather call build or deployment scripts stored under source control.

Note 2: Since it's possible to store credentials and other sensitive parameters of CI/CD chains in different places, such as Jenkins Secrets, we recommend integrating CI/CD tools with dedicated secrets management systems used in your company, such as Azure Key Vault, AWS Secrets Manager, or HashiCorp Vault.

Note 3: If your company manages both traditional applications and cloud-based (Kubernetes) applications, we at Retesys recommend using both Jenkins and Argo CD. In this scenario, Jenkins can serve as the primary CI tool for all applications, providing the flexibility and customization needed for traditional infrastructure. At the same time, Argo CD can be integrated as the CD tool specifically for managing deployments to Kubernetes environments. This approach allows for a hybrid model that leverages the strengths of Jenkins for continuous integration while utilizing Argo CD’s GitOps capabilities to manage cloud-native software efficiently. This combination ensures a cohesive CI/CD pipeline that meets the diverse needs of modern software development and deployment.

For cloud-native app deployment strategies, see our guide on 12-Factor Apps and Kubernetes.