Architectural considerations for high availability

Azure provides high availability through various means and at various levels. High availability can be at the datacenter level, the region level, or even across Azure. In this section, we will go through some of the architectures for high availability.

High availability within Azure regions

The architecture shown in Figure 2.6 shows a high-availability deployment within a single Azure region. High availability is designed at the individual resource level. In this architecture, there are multiple VMs at each tier connected through either an application gateway or a load balancer, and they are each part of an availability set. Each tier is associated with an availability set. These VMs are placed on separate fault and update domains. While the web servers are connected to application gateways, the rest of the tiers, such as the application and database tiers, have internal load balancers...