Azure Load Balancer

• Azure Load balancer operates at Layer 4 of the OSI model.

• Backend pool might consist of Azure virtual machines or Virtual Machine Scale set

• Load balancers are of two types

  • Public loadbalancer
  • Interal loadbalancer

• Azure gives loadbalancer as a service.

• Should load balancer forward the traffic to vm which has failed? To resolve this azure gives user an option to perform health checks of vms using health probes

• Health Probes can be done by tcp/http ping operations

• Load balancer sku’s

  • Basic Loadbalancer
    • Backend pool size: support upto 300 instances
    • Backend pool endpoints: Virtual machines in single availability set or virtual machine scale sets
    • Health Probes: TCP, HTTP
    • Availability Zone: Not available
    • SLA: Not available
  • Standard Loadbalancer
    • Backend pool size: support upto 1000 instances
    • Backend pool endpoints: Any virtual machines or virtual machine scale sets in a single vnet
    • Health Probes: TCP, HTTP, HTTPS
    • Availability zone: Zone-redundance is supported
    • SLA: 99.99%

• Inbound NAT rules:

  • An inbound NAT rule forwards the traffic send to Fronend Ip address & Port combination. The traffic is sent to a specific vm or instance in backend pool.
  • We use inbound NAT rules for ssh & RDP connectivity generally

• Create a load balancer Refer Here

Azure Application Gateway

• Azure Application Gateway is a web traffic load balancer that manages traffic to your web applications i.e. it works on Layer 7
• Create an application gateway Refer Here

Azure DNS

• Azure DNS is a hosting service for DNS domains that provide name resolution by using Azure infra.

• You can’t use Azure DNS to buy domains, you can buy domains in azure using app service domains.

• Azure also gives a private DNS.

• If you have purchase domain name from a different seller like godaddy, login into godaddy and change the name servers to azure nameservers

Private DNS Zone

• To Create a private dns zone