Highly Available Virtual Machines

Availability Sets

Availability Sets in Azure ensure high availability by distributing virtual machines across separate physical hardware. This prevents single points of failure by placing VMs in different faults and updating domains within a data center.

Fault Domains

Fault Domains are logical groupings within an Azure data center that represent separate physical hardware. Distributing VMs across different fault domains reduces the risk of simultaneous hardware failures affecting multiple VMs.

Update Domains

Update Domains are logical groupings within an Availability Set, ensuring that not all VMs are updated simultaneously during maintenance. Azure automatically updates VMs in different update domains, preserving application availability.

Creating High Available VM

To create a highly available VM in Azure, place it in an Availability Set. This configuration ensures that your VMs are distributed across fault and update domains to maximize uptime and minimize downtime during maintenance or failures.

Architecture for N-Tier Application

Designing a high-availability N-tier application in Azure involves using multiple Availability Sets for each tier (web, app, database) and load balancers to distribute traffic. Combining Azure services like Virtual Machines, Azure App Service, and Azure SQL Database can create a robust and scalable architecture.