Implementing GitOps with ArgoCD at Scale

At Meituan, we manage a large Kubernetes platform with thousands of applications. Implementing a consistent deployment strategy across all these applications was a significant challenge. This is how we implemented GitOps with ArgoCD to solve this problem.

Why GitOps?

Before adopting GitOps, we faced several challenges:

1. Inconsistent Deployment Methods: Different teams used different tools and approaches
2. Limited Visibility: Difficult to track what was deployed where
3. Manual Interventions: Many deployments required manual steps
4. Drift Management: Configuration drift was common and hard to detect

GitOps addresses these issues by using Git as the single source of truth for declarative infrastructure and applications.

Our ArgoCD Architecture

We implemented a multi-tenant ArgoCD setup with the following components:

1. ArgoCD Control Plane: Central management cluster running ArgoCD controllers
2. Application Sets: Used to template and manage applications across multiple clusters
3. Cluster Secret Management: Integration with Vault for secure secret management
4. Custom Health Checks: Extended ArgoCD's health checks for our specific applications

Scaling Challenges and Solutions

Scaling ArgoCD to support 10,000+ monthly deployments presented several challenges:

Challenge 1: Repository Structure

With hundreds of repositories, we needed a structure that would scale. We settled on:

• App Repositories: One repository per application or service
• Environment Repositories: Containing environment-specific configurations
• Platform Repository: Containing shared resources and cluster configurations

Challenge 2: Performance

ArgoCD's performance can degrade with thousands of applications. We implemented:

• Sharding: Running multiple ArgoCD instances, each responsible for a subset of applications
• Optimized Sync Waves: Carefully ordering synchronization to minimize dependencies
• Resource Exclusions: Excluding frequently changing resources from ArgoCD's reconciliation loop

Challenge 3: Developer Experience

To make GitOps accessible to all developers, we:

• Built a custom UI on top of ArgoCD for common operations
• Integrated with our CI system to automatically update Git repositories
• Created standardized templates for common application patterns

Results

After implementing GitOps with ArgoCD:

• Deployment frequency increased by 300%
• Mean time to recovery decreased by 70%
• Configuration drift incidents reduced by 90%
• Developer satisfaction with deployment processes improved significantly

Lessons Learned

1. Start Small: Begin with a few applications and gradually expand
2. Invest in Education: Ensure all teams understand the GitOps model
3. Automate Everything: Any manual step will become a bottleneck at scale
4. Monitor ArgoCD Itself: ArgoCD becomes a critical component that needs monitoring

Conclusion

GitOps with ArgoCD has transformed how we deploy and manage applications at Meituan. While the journey had challenges, the benefits in terms of consistency, reliability, and developer productivity have been substantial.

In my next post, I'll dive deeper into how we integrated security scanning into our GitOps workflow. ```

Let's create a sample PDF file for the resume: