Reference Architecture - Active-Active Configuration (Using CDN)

• Introduction
• Overview
• Active-Active Configuration
• Key Components
• Workflow
• CDN Configuration
• Conclusion

Introduction

Purpose

This document provides a reference architecture for designing a High Availability (HA) deployment using an Active-Active Configuration with Content Delivery Network (CDN) technology. It outlines the key components, configurations, and best practices to ensure the availability and performance of your applications and services.

Scope

This reference architecture is intended for architects, engineers, and IT professionals responsible for designing and implementing highly available systems that require redundancy and scalability.

Audience

The primary audience for this document includes technical professionals involved in designing, deploying, and managing web applications and services.

Overview

High Availability Concepts

High Availability (HA) refers to the ability of a system or service to remain operational and accessible even in the presence of failures. It involves redundancy, fault tolerance, and failover mechanisms to minimize downtime. High Availability (HA) is a critical aspect of system design and operation, especially for applications and services that require minimal downtime and uninterrupted access. Here's a more detailed explanation of the key concepts related to High Availability:

Redundancy

Redundancy involves having backup systems or components in place so that if one fails, another can take over seamlessly. Redundancy can be implemented at various levels, including hardware, software, and network components. For example, you might have redundant servers, power supplies, network connections, and even data centers.

Active-Active Configuration

Active-Active configuration involves deploying multiple instances of an application or service in different geographic locations, with all instances actively serving traffic. This configuration aims to distribute the load, reduce latency, and enhance fault tolerance. Active-Active configurations distribute the load across all instances, making efficient use of resources and enhancing fault tolerance and performance. Some of the key features of Active-Active Configuration is

Load Balancing

Traffic is evenly distributed across multiple active servers to prevent overloading any single server.

Redundancy

Multiple servers or data centers are active and operational simultaneously, providing failover capabilities.

Scalability

Active-active setups can easily scale by adding more servers to accommodate increased traffic or workloads.

Enhanced Performance

This configuration can lead to improved system performance, as resources are distributed efficiently.

High Availability

It offers a high level of availability since multiple servers can take over if one becomes unavailable.

Key Components

The architecture comprises the following key components:

CDN:

Content Delivery Networks (CDNs) play a pivotal role in content delivery by caching and efficiently serving both static and dynamic content. They utilize a network of strategically placed servers to reduce latency, enhance content retrieval speed, and ensure the reliability of online services. CDNs also serve as a line of defense against DDoS attacks, absorbing and mitigating malicious traffic to maintain service availability.

Load Balancers:

Load balancers are essential components that evenly distribute incoming user requests across a cluster of application server instances. This distribution optimizes resource utilization, prevents server overloads, and enhances system scalability. Load balancers play a critical role in ensuring that user requests are efficiently processed, improving response times and overall system reliability.

Application Servers:

Application servers serve as the backbone of web applications, hosting the application logic and databases. Deployed in multiple geographic locations, they ensure that users worldwide have access to active instances, enhancing fault tolerance and reducing latency. This geographic redundancy is essential for delivering a consistent and responsive user experience across diverse regions.

Workflow

CDN's edge servers:

Instead of going directly to a website's main server, user requests are first sent to strategically located CDN edge servers, reducing latency and enhancing content delivery speed.

Active application server:

CDNs store and deliver static web elements like images from their edge servers, while dynamic content like database-driven pages is sent to the nearest operational application server for processing.

Load balancers

Load balancers evenly distribute user requests among multiple application servers to prevent overloading any single server, ensuring better performance and fault tolerance.

Active-Active configuration

In an Active-Active configuration, multiple application servers are operational simultaneously and actively handling user requests. This setup enhances fault tolerance and high availability. If one server becomes unavailable or experiences issues, the others continue to process requests, minimizing downtime and ensuring a seamless user experience.

Data synchronization mechanisms

In a distributed system with multiple active servers, it's crucial to keep data consistent across all instances. Data synchronization mechanisms, like database replication or distributed caching systems, are employed to ensure that all servers have access to the same up-to-date data.

CDN Configuration

Cache and deliver content efficiently

Utilizing the Psychz CDN involves implementing a content delivery strategy that optimizes the performance and user experience. This typically entails setting caching policies for static resources, like images and scripts, on Psychz's edge servers. By doing so, frequently accessed content is stored closer to end-users, reducing latency and the load on your origin servers. Effective configuration ensures that content is delivered swiftly and efficiently to users worldwide, ultimately enhancing website or application responsiveness.

DDoS protection and traffic filtering

DDoS attacks can cripple online services, causing downtime and disrupting operations. Configuring DDoS protection and traffic filtering with Psychz involves implementing robust security measures to detect and mitigate malicious traffic in real-time. Psychz's tools and services can identify abnormal traffic patterns and employ countermeasures to ensure that your online assets remain accessible during attacks. This safeguarding is crucial for maintaining the availability and reliability of your online services.

Configure CDN routing

Optimizing content delivery involves configuring CDN routing to intelligently route user requests to the closest available application server. Psychz's CDN routing capabilities ensure that dynamic content requests are directed to the most geographically proximate active application server. This minimizes latency, speeds up content retrieval, and enhances the overall user experience. Proper configuration ensures that users worldwide experience fast and responsive access to your web content or applications, regardless of their location.

Conclusion

Implementing a High Availability deployment with Active-Active configuration using CDN technology offers numerous benefits, including improved performance, redundancy, scalability, and robust security. It also offers future enhancements such as multi-cloud deployments for additional redundancy and disaster recovery capabilities.

By following this reference architecture, organizations can achieve a highly available and resilient infrastructure to support critical applications and services, ensuring a seamless user experience even in the face of failures and high traffic loads.