Load Balancer, Availability Zones & Availability sets

Load Balancer

Deliver high availability and network performance to your apps altogether

1. Distributed traffic to your backend virtual machines
2. Provides high availability for your application.
3. Two types of load balancers: Public and Private
4.  Components:
   1. Frontend IP: define IP address for the load balancer
   2. Backend pool: this contains the virtual machines
   3. Health probes: monitor the health of resources in the backend pool
   4. Rules: How to distribute the incoming traffic.

Availability Zones

High availability for your mission-critical applications and data.

1. Each Availability Zone has a distinct power source, network, and cooling.
2. If one zone is compromised, then replicated apps and data are instantly available in another zone.
3. It’s your responsibility to sync applications between different VMs.

Availability sets

Provides High availability and Business continuity for applications

1. Availability Sets make use of two key concepts – Fault Domains and Update Domains. Update domains define the group of virtual machines that are going to be patched/maintained/rebooted at the same time.
2. Fault domains define the group of virtual machines that share a common power source and network switch.
3. It saves from rack-wide failure or a rack-wide maintenance window that can take down all VMS hosted on this single point of failure.
4. Availability sets are free to use! You only pay for the virtual machines being created.
5. It does not protect your application from the operating system or application-specific Failures, it does limit the impact of potential physical hardware failures, network outages, or power interruptions.