In typical Software Development Life Cycle (SDLC) setups, it’s common to have development, testing, and production clusters. However, a recurring issue we’ve observed involves the deployment strategy for management tools like ArgoCD. Specifically, deploying a single management cluster for tools like ArgoCD or even using one of the operational clusters (e.g., development) to manage deployments across the others is fraught with risks. This approach, unfortunately, is facilitated by a design choice in ArgoCD that allows a single deployment to control multiple clusters, a decision that infraheads DevOps agency considers architecturally flawed. Let's see the proper architectural strategy for using GitOps with ArgoCD and Kubernetes.
ArgoCD deployment recommendations:
Resource considerations: ArgoCD and similar GitOps operators are lightweight regarding resource consumption. Hence, each environment and cluster should ideally host its own ArgoCD deployment, tasked solely with managing its local cluster. This ensures autonomy and minimizes cross-dependency risks.
Infrastructure as code: Tools like Terraform can streamline operations by bootstrapping pre-configured Kubernetes clusters. By using the cluster name as a key parameter, you can automate subsequent processes, such as generating DNS records and setting up Kubernetes service manifest repositories for each cluster.
Repository and DNS management: Infraheads DevOps agency advocates creating a dedicated repository containing Kubernetes service manifests and corresponding DNS records for every cluster. Infraheads DevOps agency simplifies this process by automating the creation of such repositories and related configurations through a naming convention (e.g., “dev” for development environments), facilitating quick setup and troubleshooting.
Environment-specific deployments: Deploying environment-specific resources, like PR (pull request) environments in testing clusters, should automatically trigger the creation of necessary DNS records and certificates. This level of automation enhances efficiency and security by ensuring that each cluster’s resources are appropriately isolated and accessible.
Security and reliability concerns:
Utilizing a single ArgoCD instance to manage deployments across multiple clusters introduces significant risks:
Single point of failure: Centralizing control increases the impact of any single system’s compromise or failure.
Security degradation: A centralized ArgoCD model requires storing sensitive access credentials, potentially exposing all managed clusters to heightened security risks if the ArgoCD instance is compromised.
Operational Flexibility and Security:
Separating ArgoCD deployments across environments allows for safer testing of new features or upgrades in isolated environments (e.g., development) and enhances overall security. For instance, an isolated ArgoCD instance limits the scope of access to the specific cluster it manages, unlike a centralized model that necessitates broader access privileges. This model supports the principle of least privilege, significantly mitigating security risks.
Conclusion:
Through our experience and observations, including specific challenges faced when upgrading ArgoCD or testing new features, we strongly recommend adopting a decentralized approach to ArgoCD deployments. This strategy not only safeguards operational flexibility but also significantly bolsters security posture by limiting access scope and reducing the risk of widespread impact from single points of failure. Adopting GitOps principles focusing on security and reliability at the forefront is imperative for modern SDLC environments. Infraheads DevOps agency developed the turnk8s toolset to facilitate GitOps's way of turnkey Kubernetes cluster deployment and maintenance.
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