Manage Azure Application Gateway

Key Concepts

• Azure Application Gateway
• Web Application Firewall (WAF)
• Routing Rules
• Health Probes
• Autoscaling

Azure Application Gateway

Azure Application Gateway is a web traffic load balancer that enables you to manage traffic to your web applications. It operates at the application layer (Layer 7) of the OSI model, providing advanced routing capabilities such as URL-based routing, cookie-based session affinity, and SSL termination.

Example: Think of Application Gateway as a smart traffic director for your web applications. It ensures that incoming web traffic is routed to the appropriate backend servers based on predefined rules, optimizing performance and availability.

Web Application Firewall (WAF)

Web Application Firewall (WAF) is a feature of Azure Application Gateway that provides centralized protection for your web applications against common exploits and vulnerabilities. WAF operates based on rules from the OWASP (Open Web Application Security Project) Core Rule Set, helping to prevent attacks such as SQL injection, cross-site scripting, and more.

Analogy: Consider WAF as a security guard at the entrance of your web application. This guard checks every incoming request for malicious content and blocks any suspicious activity, ensuring the safety of your application.

Routing Rules

Routing Rules in Azure Application Gateway define how incoming requests are routed to backend pools. These rules can be based on URL paths, hostnames, or other criteria. Routing rules allow you to create complex routing scenarios, such as directing traffic to different backend servers based on the requested URL.

Example: Imagine routing rules as a set of instructions for a concierge at a hotel. Depending on the guest's request (URL), the concierge directs them to the appropriate room (backend server), ensuring a smooth and efficient experience.

Health Probes

Health Probes are used to monitor the health of backend servers in Azure Application Gateway. Application Gateway periodically sends health probe requests to each backend server and uses the responses to determine if the server is healthy and capable of handling traffic. Unhealthy servers are automatically removed from the backend pool until they recover.

Analogy: Think of health probes as regular health check-ups for your backend servers. Just like a doctor checks your vital signs, health probes ensure that your servers are in good condition and ready to serve traffic.

Autoscaling

Autoscaling in Azure Application Gateway allows the gateway to automatically adjust its capacity based on traffic load. This feature ensures that your application gateway can handle varying levels of traffic without manual intervention. Autoscaling can be configured to scale out (add more instances) during high traffic and scale in (reduce instances) during low traffic.

Example: Consider autoscaling as an automatic thermostat for your application gateway. It adjusts the number of instances based on the traffic load, ensuring optimal performance and cost-efficiency.

Conclusion

Managing Azure Application Gateway involves understanding and effectively using key concepts such as Web Application Firewall (WAF), routing rules, health probes, and autoscaling. By leveraging these features, you can create a robust, secure, and scalable web traffic management solution that meets the needs of your applications.