Azure Traffic Manager

Azure Traffic Manager is a DNS-based traffic load balancer that enables you to distribute traffic optimally to services hosted in Azure or even externally. It allows you to control the distribution of endpoint traffic relative to your service endpoints for improved responsiveness and availability.

What is Traffic Manager?

Traffic Manager works by resolving DNS requests for your service. You configure a set of endpoints (e.g., Azure Web Apps, cloud services, virtual machines, or even external websites) and a traffic-routing method. When a user attempts to access your service, Traffic Manager responds to their DNS query with the address of an endpoint based on the chosen routing method.

Key Features:

Traffic-routing methods: Provides various methods to direct traffic, including Priority, Weighted, Performance, Geographic, Multivalue, and Subnet.
High availability: Improves application availability by directing traffic to healthy endpoints.
Performance: Enhances performance by routing users to the closest or fastest available endpoint.
Hybrid cloud support: Can manage traffic to endpoints both within Azure and externally.
Endpoint monitoring: Continuously monitors the health of your endpoints.

Traffic-Routing Methods

Traffic Manager supports several traffic-routing methods to suit different scenarios:

1. Priority Routing

Use priority-based routing to implement failover. You can configure a primary service and then provide a list of backups that Traffic Manager directs traffic to if the primary endpoint is unavailable.

2. Weighted Routing

Distribute traffic across a set of endpoints according to weights that you assign. This is useful for gradual rollouts or A/B testing.

3. Performance Routing

Route traffic to the endpoint that provides the lowest network latency for the user. This is achieved by probing endpoints from different locations and using the response times to determine the best endpoint.

4. Geographic Routing

Direct users to specific endpoints based on their geographic location. This ensures users are directed to endpoints that are closest to them, improving performance and adhering to regulatory requirements.

5. Multivalue Routing

Returns multiple healthy endpoints in a single DNS response. This allows for failover at the client layer.

6. Subnet Routing

Route traffic to specific endpoints based on the subnet of the IP address from which the DNS query originates. This is useful for scenarios where specific IP address ranges need to be directed to particular endpoints.

Use Cases

Disaster Recovery: Ensure business continuity by failing over to a secondary region if the primary region becomes unavailable.
Improving User Experience: Deliver faster response times by directing users to the geographically closest or best-performing endpoint.
Application Upgrades: Perform zero-downtime application upgrades by gradually shifting traffic to a new version of your application.
Hybrid Cloud Architectures: Seamlessly manage traffic between on-premises resources and cloud-based services.

Important Considerations

Traffic Manager is a DNS-level load balancer. It does not inspect the actual content of network traffic. For layer 7 load balancing and advanced traffic management features, consider Azure Application Gateway.

Getting Started

To start using Azure Traffic Manager:

Create a Traffic Manager profile in the Azure portal.
Configure your endpoints (e.g., Azure Web Apps, VMs, external URLs).
Select your desired traffic-routing method.
Configure endpoint monitoring settings.
Traffic Manager will provide a DNS name for your profile, which you can use in your applications or DNS records.

For detailed configuration steps and advanced scenarios, please refer to the official Azure Traffic Manager documentation.


# Example of configuring Traffic Manager profile (conceptual)
az network traffic-manager profile create \
    --name MyTrafficManagerProfile \
    --resource-group MyResourceGroup \
    --routing-method Performance \
    --unique-dns-label myapptraffic

az network traffic-manager endpoint create \
    --name MyWebAppEndpoint \
    --profile-name MyTrafficManagerProfile \
    --resource-group MyResourceGroup \
    --type azureEndpoints \
    --target-resource-id /subscriptions/YOUR_SUB_ID/resourceGroups/MyResourceGroup/providers/Microsoft.Web/sites/MyWebApp \
    --priority 1 \
    --weight 100 \
    --endpoint-status Enabled

MSDN Documentation

Azure