Azure Traffic Manager

Last updated: September 10, 2023

Azure Traffic Manager is a DNS-based traffic load balancer that enables you to distribute traffic optimally to your services, both in the cloud and in your on-premises environment. Traffic Manager allows you to control the distribution of user traffic by using the DNS feature of Traffic Manager. You provide a DNS name to your Traffic Manager profile, and Traffic Manager directs incoming DNS requests to the most appropriate endpoint based on a traffic-routing method you configure.

Introduction to Traffic Manager

In today's globalized world, applications are often deployed across multiple regions to ensure high availability, disaster recovery, and optimal performance for users worldwide. Azure Traffic Manager plays a crucial role in managing this distributed architecture by intelligently directing traffic to the most suitable endpoint. This can be a public IP address, a fully qualified domain name (FQDN), or an Azure resource.

Core Concepts

• Traffic-routing methods: Traffic Manager supports several traffic-routing methods to control how traffic is directed to your endpoints. These include:
  • Priority: Directs all traffic to a primary endpoint until it becomes unavailable, then shifts traffic to a secondary endpoint, and so on.
  • Weighted: Distributes traffic across a set of endpoints based on predefined weights.
  • Performance: Routes users to the endpoint that provides the lowest network latency.
  • Geographic: Routes users to an endpoint located in the same geographic location as the user.
  • Multivalue: Returns multiple healthy endpoints for a DNS query, allowing the client to choose.
  • Subnet: Maps subsets of IP address ranges to specific endpoints.
• Endpoints: These are the locations where your application or service is hosted. Endpoints can be Azure services (like VMs, App Services, or Public IP addresses), or external endpoints outside of Azure.
• Health Probes: Traffic Manager continuously monitors the health of your endpoints using configurable probes. If an endpoint becomes unhealthy, Traffic Manager automatically reroutes traffic to healthy endpoints.
• Profiles: A Traffic Manager profile defines the DNS name, traffic-routing method, and endpoints for your service.

Deployment Models

Traffic Manager can be used to manage traffic for various deployment scenarios, including:

• Disaster Recovery: Ensure your application remains available even if one region experiences an outage.
• High Availability: Distribute traffic across multiple instances of your application to prevent overload and ensure consistent availability.
• Performance Optimization: Route users to the closest or best-performing datacenter for a faster user experience.
• Application Upgrades: Perform rolling updates by gradually shifting traffic to a new version of your application.

Common Scenarios

Here are some practical use cases for Azure Traffic Manager:

• Global Application Deployment: Deploy your web application across multiple Azure regions (e.g., North Europe, West US) and use Traffic Manager with the Performance routing method to direct users to the datacenter closest to them.
• Failover for Critical Services: Set up your critical application in a primary region and a secondary region for disaster recovery. Use the Priority routing method to automatically failover to the secondary region if the primary region becomes unavailable.
• Load Balancing Internal Services: Distribute traffic to multiple internal instances of an application using the Weighted routing method for efficient resource utilization.

Configuration Guide

Configuring Traffic Manager involves several steps:

1. Create a Traffic Manager profile: In the Azure portal, navigate to Traffic Manager profiles and create a new profile.
2. Choose a DNS name: Select a unique DNS name for your profile (e.g., my-awesome-app.trafficmanager.net).
3. Select a traffic-routing method: Choose the routing method that best suits your needs (Priority, Weighted, Performance, etc.).
4. Add endpoints: Define the endpoints for your application, specifying their type, IP address or FQDN, and priority/weight if applicable.
5. Configure health probes: Set up health probes to monitor the availability of your endpoints.

Example: Creating a Traffic Manager Profile with Azure CLI

The following Azure CLI command demonstrates creating a Traffic Manager profile with the 'Performance' routing method:

For detailed steps and options, refer to the official Azure documentation on creating a Traffic Manager profile.

Monitoring and Management

Once your Traffic Manager profile is active, you can monitor its performance and the health of your endpoints through the Azure portal. Traffic Manager provides:

• Endpoint health status: View the current status of each endpoint.
• Traffic statistics: Analyze traffic patterns and DNS query volumes.
• Alerting: Set up alerts for critical events, such as endpoint failures.

You can also manage your profile by adding or removing endpoints, changing routing methods, and adjusting probe configurations.

Troubleshooting

Common issues with Traffic Manager can include:

• Endpoints not appearing healthy: Verify that your health probes are correctly configured and that the endpoints are accessible from the probe locations.
• Traffic not being routed as expected: Double-check your traffic-routing method and endpoint configurations.
• DNS resolution issues: Ensure that your DNS client is correctly configured to use your Traffic Manager profile's DNS name.

If you encounter persistent issues, consult the Azure Traffic Manager troubleshooting guide for more in-depth solutions.