In the previous article on load balancing, we showed how easy it is to create a new service with Traffic Manager, which can use a range of different algorithms to distribute the workload. In this article we will look at how we monitor the performance and health of all the web servers under control of Traffic Manager.
If you want to take a web server node out of service manually, it is easy to change state from active to draining or disabled using the simple drop-down menu. But if that node fails unexpectedly, Traffic Manager will identify the problem, route traffic away from that node, and raise an alert to let you know there's a problem.
So let’s imagine you are receiving traffic requests through at a steady rate of about 100 transactions a second. Using the activity monitor, you can see that Traffic Manager is evenly balancing the workload across three web server nodes in the pool. This pie chart shows how each of the three nodes in this resource pool is handling approximately one-third of the traffic:
When that web server has recovered, Traffic Manager notices that node has come back again, and starts to redistribute the workload. Traffic is wound back up again, and as you can see from the status messages, we are back to green, and we are back to full capacity.