This course covers the Architect ARM Networks part of the 70-534 exam, which is worth 5 - 10% of the exam. The intent of the course is to help fill in an knowledge gaps that you might have, and help to prepare you for the exam.
Welcome back. In this lesson, I'll cover Traffic Manager.
Traffic Manager allows you to load balance traffic to your internet facing services at the DNS level. Since Traffic Manager operates at the DNS level, it allows you to point your domain name to Traffic Manager with a CNAME record, and have Traffic Manager redirect the requests to the correct endpoint, based on whichever mode you're using.
Now, Traffic Manager has three modes of operation, which are Priority, Weighted, and Performance. Let's go through each of these options.
The Priority option is better known as failover. It works by directing all requests to a primary endpoint unless that endpoint is down, and then it directs it to a secondary endpoint. It's common to have a backup of an environment in case of failure, and that's where the Priority method comes in handy.
The way it works is that you specify a list of endpoints in priority order, and Traffic Manager will send the traffic to the highest priority endpoint that's available. If you're thinking about high availability, especially cross-region availability, then this is a fantastic option.
Now, the next option is Weighted, which is similar to Round Robin, in that the intent is to evenly distribute requests. So, requests are distributed across the different endpoints at random, however, the chance of any given endpoint being selected is based on the weighted values that you define for each endpoint, if you want an even distribution, and assign equal weights to all of the endpoints.
Now, being able to change the weights gives a lot of flexibility, and it's a great way to perform Canary Deployments as well as application migrations.
Okay, I mentioned there were three different modes for Traffic Manager, and the final one is Performance mode. And, this is where you have geographically separated endpoints, and Traffic Manager will select the best one per request based on latency.
By having your endpoints cross region, and using performance based routing, you can ensure that your end users are getting the best possible user experience. And that's because they're always going to be directed to an endpoint with the lowest latency for them. Now, this tends to be the one that is physically closer to them, however, that is not a rule.
Okay, that's going to wrap up this lesson. This was a brief overview, and if you're in charge of implementing a Traffic Manager setup, I recommend looking into the documentation further, however, from an architectural point of view, it shows you how you can have highly available systems, with very simple patterns here.
So, in the next lesson, I'm going to cover VPNs and Express Route, so if you're ready to keep learning, then let's get started in the next lesson.
About the Author
Ben Lambert is a software engineer and was previously the lead author for DevOps and Microsoft Azure training content at Cloud Academy. His courses and learning paths covered Cloud Ecosystem technologies such as DC/OS, configuration management tools, and containers. As a software engineer, Ben’s experience includes building highly available web and mobile apps. When he’s not building software, he’s hiking, camping, or creating video games.