Azure Traffic Manager is a DNS-based traffic load balancer that enables you to distribute traffic optimally to services across global Azure regions, while providing high availability and responsiveness.
What this mean is that you can distribute the traffic your web application receives across different regions throughout the world and this is a great Azure feature – other features like the Azure Load Balancer and Application Gateway cant distribute traffic across regions.
Azure Traffic Manager has a number of routing methods and its important to know the options available and what you can use them for: –
- Priority: Use Priority when you want to use a primary service endpoint for all traffic, and provide backups in case the primary or the backup endpoints are unavailable.
- Weighted: Use Weighted when you want to distribute traffic across a set of endpoints, either evenly or according to weights, which you define.
- Performance: Use Performance when you have endpoints in different geographic locations and you want end users to use the “closest” endpoint in terms of the lowest network latency.
- Geographic: Use Geographic so that users are directed to specific endpoints (Azure, External, or Nested) based on which geographic location their DNS query originates from. This empowers Traffic Manager customers to enable scenarios where knowing a user’s geographic region and routing them based on that is important.
- Multivalue: Use MultiValue for Traffic Manager profiles that can only have IPv4/IPv6 addresses as endpoints. When a query is received for this profile, all healthy endpoints are returned.
- Subnet: Use Subnet traffic-routing method to map sets of end-user IP address ranges to a specific endpoint within a Traffic Manager profile. When a request is received, the endpoint returned will be the one mapped for that request’s source IP address.
A good example of why Traffic Manager is super awesome, lets say you have your web app running in the North Europe region, all users get directed to this region, what would happen if this region were to go down, not good! – with Traffic Manager you could have a second region (lets say UK South for this example) which has a copy of the web application and If the first region (North Europe) were to go down then Traffic manager would move all of your traffic to the second region meaning your website stays up and running, your users stay happy and bingo, now you have a highly available web application, this is known as performing a failover, also note your now paying for both regions but you have the added reliability and high availability your users may demand.
On a project at work we had a requirement which was basically make the website responsive to users around the globe, one way to aid in this is to use Traffic Manager and implement the Performance routing method, we had a copy of the web application deployed to 3 or 4 regions and when users would hit the website they would be directed to their nearest region which helps with faster response times.
You can read the official documentation on Azure Traffic Manager for lots more information.