Managing Multi-Cluster Kubernetes Deployments with ArgoCD and Crossplane

Introduction

As organizations embrace Kubernetes, the challenge shifts from running a single cluster to managing multiple clusters across regions, environments, and teams. Manual deployment processes and ad-hoc configurations don’t scale well in such setups. GitOps, treating Git as the source of truth for both application and infrastructure state, emerges as a solution.

However, managing multi-cluster workloads requires more than just GitOps. It needs powerful orchestration and automation frameworks. This is where ArgoCD and Crossplane come in: ArgoCD automates application deployment, while Crossplane extends GitOps principles to cloud infrastructure provisioning. Together, they enable a scalable, consistent, and self-service model for multi-cluster DevOps.

This blog explores how GitOps scales beyond single clusters, the architectural patterns for multi-cluster management, and best practices to build resilient, cloud-native platforms.

Architecture Overview

Architecture Explanation:

The architecture shows a multi-cluster GitOps pipeline powered by ArgoCD and Crossplane.

• Git Repositories hold application manifests (Helm, Kustomize, YAML) and infrastructure definitions (Crossplane CRDs).
• ArgoCD continuously reconciles application repos and syncs workloads to multiple Kubernetes clusters across regions.
• Crossplane provisions cloud infrastructure like Amazon RDS, Amazon VPCs, Amazon S3, or Amazon EKS clusters, using Kubernetes-native CRDs stored in Git.
• Cluster Registry or hub cluster acts as the control plane, while worker clusters run workloads across dev, staging, and prod.
• Policy Engine (OPA/Gatekeeper) enforces Amazon Guardrails for compliance and security.
• Observability tools like Prometheus, Grafana, and Loki provide visibility across clusters.

This model ensures that infrastructure and applications are versioned, peer-reviewed, and deployed consistently across environments.

The Shift: From Single-Cluster GitOps to Multi-Cluster GitOps

Traditional GitOps focuses on syncing workloads to one cluster. But enterprises often need multiple clusters for:

• Geo-distribution for latency reduction.
• Isolation between dev, staging, and production.
• Scaling teams and applications independently.

Multi-cluster GitOps extends the model by centralizing policies while decentralizing deployments, ensuring autonomy without chaos.

Core Pillars of GitOps at Scale

1. Declarative Infrastructure & Applications

• Both infra (Crossplane CRDs) and apps (Helm/Kustomize) live in Git.
• Git history = single source of truth.

2. Continuous Reconciliation

• ArgoCD agents reconcile cluster state with Git repos.
• Drift is detected and auto-corrected.

3. Separation of Concerns

• Platform teams manage infra repos.
• App teams manage workload repos.
• Security & compliance policies applied centrally.

4. Policy-Driven Governance

• TOPA/Gatekeeper enforces compliance (e.g., no public Amazon S3 buckets, RBAC rules).
• Policies are codified as code and stored in Git.

Challenges in Multi-Cluster GitOps

Cluster Sprawl

• Managing dozens of clusters across accounts and clouds.
• Solution: Maintain a hub-and-spoke model with a centralized ArgoCD control plane.

Secret Management

• Distributing secrets securely across clusters.
• Solution: External secret stores (AWS Secrets Manager, HashiCorp Vault) integrated with GitOps workflows.

Drift and Divergence

• Teams are making manual changes on clusters.
• Solution: Enforce strict GitOps pipelines and enable automated drift correction.

Scaling Observability

• Aggregating metrics/logs across multiple regions.
• Solution: Use a centralized observability stack with federation support.

Best Practices for GitOps at Scale

1. Adopt a Multi-Repo Strategy

• Infra, apps, and policies live in separate repos.
• Reduces the blast radius of changes.

2. Use a Control Plane Cluster

• Run ArgoCD and Crossplane centrally.
• Sync workloads into target clusters.

3. Automate Everything

• Infrastructure provisioning (Crossplane).
• App deployment (ArgoCD).
• Compliance enforcement (OPA).

4. Enable Progressive Delivery

• Use Argo Rollouts for canary/blue-green deployments.
• Combine with metrics-driven rollbacks.

5. Centralize Observability

• Multi-cluster monitoring dashboards in Grafana.
• Global alerting policies.

Outcomes of Multi-Cluster GitOps

• 70% reduction in manual ops overhead, infra, and apps provisioned automatically via Git.
• Consistent deployments across dev, staging, and prod.
• Faster onboarding for developers, self-service clusters, and infra through Git PRs.
• Improved compliance, guardrails enforced as code.
• Reduced MTTR, auto-healing clusters, and infra rollbacks.

Conclusion

Multi-cluster GitOps with ArgoCD and Crossplane is more than a deployment strategy, it’s a blueprint for enterprise-scale DevOps. It standardizes how applications and infrastructure are managed across clouds and teams.

As enterprises expand into hybrid and multi-cloud strategies, GitOps at scale will be the foundational operating model enabling velocity without losing control.

Drop a query if you have any questions regarding ArgoCD or Crossplane and we will get back to you quickly.

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