1. Introduction | Why Build a Private CDN?

1.1 Are You Facing These Challenges?

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As your business expands nationally and globally, content delivery often encounters the following 4 major challenges:

1. Lack of Control and Limited Customization Public CDNs’ standardized rules make it difficult to flexibly adjust caching strategies, routing algorithms, or security checks. Compliance-sensitive industries require greater control over data and customizable logic.

2. Unpredictable Performance and Stability Shared nodes can experience congestion or throttling. High concurrency and traffic surges can make it difficult to guarantee SLAs, directly impacting user experience and revenue.

3. High Bandwidth and Distribution Costs The larger the traffic volume, the more expensive pay-as-you-go pricing becomes. Building simple proxies lacks enterprise-grade optimization, making it difficult to strike a balance between cost and performance.

4. Data Security and Privacy Compliance Pressures GDPR, HIPAA, and various local regulations require controllable data storage and transmission paths. The “black box” nature of public platforms makes it difficult to meet audit and compliance requirements.

Traditional public CDNs, cloud provider edge nodes, or simple reverse proxy solutions struggle to address all of these pain points simultaneously. They either lack flexibility, are costly, or involve complex operations and inadequate observability.

1.2 Why Choose OpenResty Edge?

OpenResty Edge is a modern edge computing platform built on OpenResty, providing enterprises with a complete solution for building private CDN networks:

• High-Performance Edge Processing Capabilities: Based on the high-performance architecture of Nginx + LuaJIT, OpenResty Edge can efficiently process a large number of requests at edge nodes, reducing origin server pressure and improving user experience. This high-performance architecture is particularly suitable for business scenarios requiring fast response and high concurrency processing.

• Flexible Architecture Deployment: Supporting various deployment modes and cluster management, OpenResty Edge allows enterprises to choose the appropriate deployment method according to their needs and flexibly scale their network. This flexibility enables businesses to quickly adapt to market changes and business growth.

• Native Support for Edge Computing: Built-in EdgeLang + Lua extensibility enables complex business logic execution at the edge nodes, such as content personalization and security checks, reducing reliance on origin servers. This capability allows enterprises to implement more intelligent content distribution and security policies at the edge.

• Complete DevOps Integration: Providing both SDK and web console operation paths simplifies operation and maintenance processes, improving management efficiency. Enterprises can leverage automation tools for rapid deployment and management, reducing operating costs and enhancing overall operational efficiency.

2. Architecture Design | A Flexible Multi-Tier Edge Architecture

2.1 Core Components of a Private CDN

A private CDN network primarily consists of the following core components:

• OpenResty Edge Node Gateway Nodes: Edge servers deployed in various geographical locations.
• OpenResty Edge Admin Management Node: A unified configuration management and monitoring platform, along with intelligent DNS scheduling services.
• Origin Server: The storage location for the original content.

2.2 Network Topology Architecture

User Request → DNS Resolution → Nearest Edge Node → Cache Hit/Origin Fetch → Content Return
                                ↓
                        Edge Admin Management Node (Configuration Distribution, Monitoring)

2.3 Multi-Tier Network Architecture Support

• When a user requests the nearest Edge Node, and the link to the origin server is suboptimal, a multi-tier network can forward the request to another Edge Node with a better link, significantly reducing latency and ensuring availability.
• Regional Node → Edge Node → Origin Server: Multi-tier network architecture, next hop selection based on policy, tiered origin fallback.
• Automatic Edge Node Scaling and Health Checks: Automatic bypass of failed nodes ensures service continuity.

For more practical examples and configuration documentation, please refer to: Multi-Tier Network Configuration Guide

2.4 Edge Computing Capabilities: EdgeLang + Lua Support

• OpenResty Edge has a built-in powerful edge computing engine that allows business logic to be “executed close to the user,” commonly used for image processing, content personalization, A/B testing, security checks, and other advanced features.
• EdgeLang: A DSL designed for edge scenarios with simple syntax and ease of use. For detailed syntax and introduction, please see Edge Language User Manual.
• Lua Scripting: Full LuaJIT ecosystem support enables complex request/response rewriting, dynamic authentication, and more. For more information, see Global Lua Modules.
• Real-time Processing: Executing business logic directly on edge nodes reduces the load on the origin server, and millisecond-level dynamic decisions significantly improve user experience.
• Integrated Computing and Caching: Enables an edge architecture with data cached and computed close to the user.

3. Installation and Deployment | Quick Start Your Edge Network

3.1 OpenResty Edge Node Planning

Geo-location Selection Strategy — Optimizing User Experience and Cost Structure

• Intelligently plan node deployment based on user distribution, minimizing the physical distance between end-users and edge nodes, and reducing access latency.
• Evaluate deployment plans by combining bandwidth costs and network topology, optimizing operational costs while ensuring performance.
• Support flexible node scaling and shrinking, reserve horizontal scaling space, and adapt to business peaks and global expansion needs.

Recommended Node Configuration — Balancing Performance and Resource Investment

OpenResty Edge provides reference configurations to help technical teams efficiently implement node deployment:

• CPU: Select the appropriate number of CPU cores based on the concurrent request volume to avoid resource waste.
• Memory: Cache capacity directly affects the hit rate. It is recommended to configure sufficient memory to improve edge processing efficiency.
• Storage: SSD is recommended to ensure the response speed of high-concurrency I/O requests.
• Network: Ensuring that nodes have stable bandwidth and low-latency connections is core to guaranteeing service quality.

3.2 Rapid Deployment: Simplified Configuration, Lowering the Barrier to Entry

During system implementation, OpenResty Edge provides a clear, controllable, and automated deployment mechanism, ensuring that enterprises can quickly build their own CDN network without a large DevOps team.

Standardized OpenResty Edge Installation Process

• Provides detailed documentation and standardized processes. For detailed installation steps, please refer to: Installing OpenResty Edge

Flexible Cluster Management Configuration

• Supports one-click deployment and initialization through the console.
• Node registration and online process are transparent and easy to track.
• Offers deployment methods including physical machines, virtual machines, and Kubernetes, supporting large-scale Kubernetes cluster deployments and compatibility with mainstream infrastructure environments.

For detailed configuration steps, please refer to: Gateway Cluster

3.3 Rapid Business System Integration: Flexible DNS Integration and Unified Management of Multiple Businesses

After deployment, the business integration process is equally simple and efficient:

• After creating an application and publishing the configuration in the console, the system will automatically distribute the configuration to the edge nodes.
• Add a CNAME record pointing to the OpenResty Edge domain in the DNS provider’s console.
• Supports unified management of multiple applications and domains, facilitating unified operation and maintenance across business lines.

4. DNS Management and Intelligent Scheduling | Building Highly Available Access Paths

4.1 DNS Access Configuration

You can choose between the following two DNS management methods:

Method 1: Self-Managed DNS

• Use your own DNS service or a third-party service.
• Configure DNS records to resolve to OpenResty Edge nodes.

Method 2: OpenResty Edge as Authoritative DNS

• Directly use OpenResty Edge as the authoritative DNS server.
• Manage all DNS records centrally.

For detailed configuration information, please refer to: DNS Configuration

4.2 DNS and GSLB (Global Server Load Balancing)

Intelligent Scheduling Policies

• Geo-location based scheduling: Directs users to the nearest edge node based on their geographical location.
• IP attribution scheduling: Optimizes routing paths based on the user’s ISP network.
• System load scheduling: Monitors edge node load in real-time and dynamically adjusts traffic distribution based on metrics like system load or QPS.

For detailed operational steps and information, please refer to the following documents:

1. Enabling DNS Global Server Load Balancing
2. DNS workflow

Automatic Failover

• Health Checks and Automatic Failover

For details on configuring DNS health checks, please refer to: DNS Health Checks

5. Cache Management | Designed for Performance and Hit Rate

5.1 Application-Level Cache Policy Configuration

Enabling Caching

If you want to improve the access efficiency of static resources or API responses, we recommend enabling the caching feature. For specific configuration methods, please refer to this document: Proxy Cache

Cache Rule Examples

Content Type	Cache Duration	Applicable Scenarios
Static Resources (CSS/JS/Images)	24 hours - 7 days	Infrequently changing resources
Dynamic Content (HTML)	5 - 30 minutes	Semi-dynamic pages
API Responses	30 seconds - 5 minutes	Micro-caching strategies

Cache Configuration Dimensions

• Supports configuration dimensions such as path, method, and status code, helping businesses flexibly adjust caching strategies based on different business needs, ensuring efficient resource utilization.
• Custom caching rules allow businesses to optimize caching based on specific business logic and user behavior patterns, thereby improving user experience and system performance.
• Conditional caching and exclusion rule settings provide more granular control, ensuring the accuracy and effectiveness of caching strategies.

5.2 Cache Consistency and Refresh Mechanism

Cache Invalidation

• API refresh interface provides a convenient cache management method, ensuring that businesses can quickly respond to content update needs and maintain a consistent user experience.
• Invalidation by path and tag¹ supports large-scale content update scenarios, reducing the complexity of manual operations.
• Automatic origin fallback mechanism ensures that the latest content can be obtained in time when the cache expires, guaranteeing service continuity and reliability.

Cache Preheating

Currently, cache preheating can be achieved by writing scripts to send requests to access OpenResty Edge ². This feature helps pre-load key content before peak periods, reducing first-time access latency and improving user experience.

5.3 Edge Cache Logic Extension

• Leverage EdgeLang/Lua for dynamic control over caching logic, enabling personalized caching based on device, user, and other dimensions, enhancing user experience while optimizing resource utilization.
• Support personalized caching based on device, user, and other dimensions, ensuring the needs of different user groups are met and improving overall service quality.
• Fine-grained cache control enhances user experience by reducing unnecessary origin requests through more granular caching strategies, thereby improving system response speed.

6. Security Protection | Flexible and Controllable Full-Link Security System, Guaranteeing Business Stability and Data Compliance

OpenResty Edge provides a full-link security mechanism covering the transport layer to the application layer, supporting flexible policy configuration and refined management to meet compliance requirements and ensure business continuity and security boundary autonomy.

6.1 HTTPS Certificate Management | Simplified Process, Reduced Maintenance Costs

Supports the complete certificate lifecycle management, enabling rapid deployment and continuous data transmission security. Suitable for enterprises looking to flexibly and uniformly manage HTTPS across multiple applications and domains.

• Automatic Let’s Encrypt Certificate Application: Supports domain validation and automatic renewal, reducing certificate maintenance burden.
• Import Custom Certificates: Supports enterprise-owned certificates, meeting higher security standards and customization requirements.
• Hot Certificate Renewal: Supports zero-downtime certificate replacement, ensuring service continuity.

6.2 Application-Level Security Policy Configuration | On-Demand Customization, “Programmable” Policies

Unlike traditional CDNs that rely on fixed rules, we support business-aware, customizable security policies:

IP Access Control

• Fine-grained configuration of IP whitelists and blacklists, page rules, and controlling the entry of risky traffic.
• Supports configuration cascading and granular authorization.

For details, please refer to the configuration documentation: Create IP List

DDoS Protection

• Automatic detection of high-concurrency attacks
• Supports dynamic rate limiting and traffic shaping policies for adaptive defense against abnormal traffic

For more information, please refer to the configuration documentation: Limit Traffic and Limit Rate

WAF (Web Application Firewall)

• Supports flexible rule writing to block specific attack behaviors
• Real-time threat monitoring and response mechanisms

For detailed configuration, please refer to the documentation: WAF

6.3 Authentication and Edge Validation Logic | Reduce Origin Server Pressure, Protect Content Assets

We offer a variety of flexible edge authentication mechanisms to make access control more intelligent and closer to the user:

• JWT Verification: Supports standard token verification, compatible with third-party authentication systems
• URL Signature Mechanism: Prevents hotlinking and restricts unauthorized external access
• Time-Limited URL Support: Configures access time windows to ensure sensitive content is not exposed for extended periods
• Custom Lua Logic: Implements dynamic authentication based on business rules, reducing reliance on and pressure on the origin server

7. Monitoring and Operations | An Observability and Automation System for Business Continuity

After deploying a private CDN, the system’s stability, performance, and ability to quickly locate and repair faults become crucial for continuous operation.

7.1 Real-time Monitoring Dashboard | Performance and Risks at a Glance

To help technical teams grasp traffic dynamics and node status in real time, OpenResty Edge provides a visual monitoring dashboard.

Dynamic Metrics

• Key business indicators: traffic, response time, cache hit ratio, status code distribution, etc.
• Performance bottleneck discovery: abnormal responses, rising error rates, node load trends
• Real-time analysis capabilities: combines dynamic indicators with historical trends to support rapid decision-making and capacity forecasting

For detailed configuration, please refer to the documentation: Dynamic Metrics³

7.2 Log and Metric Collection | Flexible Integration with Enterprise Monitoring Systems

OpenResty Edge provides built-in monitoring capabilities and seamless integration with mainstream tools.

Built-in Log Collection

• OpenResty Edge automatically collects error logs, which, combined with dynamic metrics, satisfy most monitoring needs.
• Provides a complete access log collection mechanism, supporting auditing, traceback, and behavior analysis.

External Log Analysis

For more detailed log collection and analysis, different systems can be integrated to achieve more complex log analysis and alerting strategies:

• Collect OpenResty Edge Node access logs.
• Use tools like the ELK Stack for log analysis and alerting.

Through these capabilities, users can easily integrate into existing operational workflows without the need to rebuild the system.

Key Metrics Monitoring

In OpenResty Edge, key metrics monitoring covers various aspects, including performance, availability, and resource utilization. Performance metrics include response time, throughput, and cache hit ratio. Availability metrics focus on service uptime, error rate, and node health. Resource metrics monitor CPU usage, memory usage, and disk I/O. Real-time monitoring and analysis of these metrics help technical teams quickly identify and resolve potential issues, ensuring system stability and efficiency.

7.3 Operational Optimization Capabilities

Performance Tuning Strategies

1. Cache Parameter Optimization: Adjust caching strategies based on monitoring information.
2. Network Optimization:
   • Enable HTTP/2 and HTTP/3 support.
   • Configure appropriate TCP parameters.
   • Use connection reuse to reduce handshake overhead.
3. Deep Analysis: Use OpenResty Xray for monitoring and analysis.

HTTP/3 configuration method can be found here: Enabling HTTP/3 Support

Failure Alerting Mechanism

Ways to implement failure alerting:

1. Utilize OpenResty Edge’s built-in alerting functionality.
2. Use Prometheus + Grafana for monitoring and alerting.

Configuration details can be found in: Monitoring OpenResty Edge

Disaster Recovery and Backup Strategy

Database High Availability Configuration: A highly available database configuration is crucial for ensuring system stability and data security. OpenResty Edge offers various deployment solutions for database clusters and master-slave architectures, allowing flexible selection based on specific business needs. Below are detailed setup guides:

• High-Availability Database Cluster Management Tool for OpenResty Edge
• Configuring OpenResty Edge Database High Availability Using Interactive Scripts

Data Backup: To ensure the security of configuration and management data, regular cold backups of the Edge Admin database are recommended. Detailed operational steps and precautions can be found in: OpenResty Edge Database Backup

SDK and Web Console

• Dual operation paths support automated operations.
• Hot updates for configuration changes with zero downtime.
• Health checks and automatic alerting mechanisms.

8. Summary | Build Your Own Edge Network System

OpenResty Edge, through its underlying high-performance architecture and orchestratable modular design, provides enterprises with a path from proof-of-concept to full production deployment for private CDNs and edge computing. Whether a startup or a multinational corporation, businesses can scale on demand based on the same platform, flexibly integrate with existing systems, and achieve continuous business evolution and cost optimization.

• Underlying Design: High Performance + High Concurrency The deep integration of Nginx and LuaJIT, complemented by an event-driven model and efficient memory management, provides edge nodes with millisecond-level response capabilities and the ability to handle billions of concurrent requests, ensuring smooth business operation even during peak traffic.

• Architectural Flexibility Support for hybrid deployments (physical machines, virtual machines, Kubernetes) ensures consistency in deployment methods and operational models.

• Rapid Deployment and Seamless Integration One-click installation scripts and Kubernetes batch deployment capabilities help teams launch their first nodes within hours; traffic can be smoothly cut over via CNAME/DNS without affecting existing online services, minimizing migration risks.

• Ultimate Flexibility in Caching and Rules The EdgeLang DSL + Lua dual-language solution covers the entire chain from visual configuration to fine-grained logic orchestration and personalized caching. Enterprises can customize lifecycles and origin strategies based on content type, user profiles, device characteristics, and other dimensions, significantly improving cache hit rates and reducing origin bandwidth consumption.

• Multi-Dimensional Security System, “First Line of Defense” Close to the Business From automated TLS certificates, WAF, and DDoS defense to custom edge authentication, OpenResty Edge pushes security capabilities down to the nodes closest to users, achieving “detection and blocking” while meeting compliance and privacy requirements.

• Observability and Debugging Capabilities Built-in dashboards and native integration with Prometheus/Grafana/ELK provide real-time visibility into traffic, performance, and health status; combined with Edge Xray’s deep flame graph analysis, engineers can quickly locate bottlenecks and troubleshoot issues.

• Extensibility and Secondary Development Support Public SDKs, WebHooks, and plugin mechanisms allow businesses to tightly embed Edge into CI/CD and AIOps processes; custom modules can be easily built based on the Lua ecosystem to meet differentiated needs.

• Long-Term Cost Optimization Private deployment avoids ongoing external CDN traffic charges, while intelligent caching and proximity-based origin requests reduce cross-regional bandwidth; unified operations and automated deployment significantly reduce labor costs, keeping TCO steadily declining within a controllable range.

• Reliable Technical Support and Services The OpenResty team provides 7x24 enterprise-grade support, best practice consulting, and custom development services, helping customers navigate every step from PoC to large-scale deployment with stability and efficiency.

With OpenResty Edge, you will have a secure, controllable, resilient, and easy-to-operate edge network system, laying a solid foundation for future business innovation and standing out in the fierce market competition.

Appendix

Frequently Asked Questions (FAQ)

Q: How do I estimate the number of edge nodes required for deployment? A: We recommend planning based on user geographical distribution, anticipated concurrency, and latency requirements. Start with core regions and gradually expand as needed.

Q: Which operating systems and deployment methods are supported? A: We support mainstream Linux distributions. Deployment can be done via traditional installation, containerization (e.g., Docker), or Kubernetes.

Q: How does the edge computing capability support complex business scenarios? A: EdgeLang + Lua extensions enable the implementation of complex logic on edge nodes, such as authentication, A/B testing, personalized recommendations, and real-time data processing. This significantly reduces origin server requests and enhances user experience.

Related Documentation Links

• OpenResty Edge
• Installation and Upgrade
• Edge Admin User Manual
• OpenResty Edge? Operations

What is OpenResty Edge

OpenResty Edge is our all-in-one gateway software for microservices and distributed traffic architectures. It combines traffic management, private CDN construction, API gateway, security, and more to help you easily build, manage, and protect modern applications. OpenResty Edge delivers industry-leading performance and scalability to meet the demanding needs of high concurrency, high load scenarios. It supports scheduling containerized application traffic such as K8s and manages massive domains, making it easy to meet the needs of large websites and complex applications.

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About The Author

Yichun Zhang (Github handle: agentzh), is the original creator of the OpenResty^? open-source project and the CEO of OpenResty Inc..

Yichun is one of the earliest advocates and leaders of “open-source technology”. He worked at many internationally renowned tech companies, such as Cloudflare, Yahoo!. He is a pioneer of “edge computing”, “dynamic tracing” and “machine coding”, with over 22 years of programming and 16 years of open source experience. Yichun is well-known in the open-source space as the project leader of OpenResty^?, adopted by more than 40 million global website domains.

OpenResty Inc., the enterprise software start-up founded by Yichun in 2017, has customers from some of the biggest companies in the world. Its flagship product, OpenResty XRay, is a non-invasive profiling and troubleshooting tool that significantly enhances and utilizes dynamic tracing technology. And its OpenResty Edge product is a powerful distributed traffic management and private CDN software product.

As an avid open-source contributor, Yichun has contributed more than a million lines of code to numerous open-source projects, including Linux kernel, Nginx, LuaJIT, GDB, SystemTap, LLVM, Perl, etc. He has also authored more than 60 open-source software libraries.