Azure VMSS Concepts

• VMSS Orchestration Modes:
  • ScaleSetVMs: VMs can be added based only on the scaleset configuration.
  • VM: Virtual Machines outside Scaleset can be explicitly added to the VMSS
• Scaling:
  • Scaling VMs can be done by using the metrics collected by Azure Monitor.
  • For app servers and web servers we use Percentage CPU

Azure Load Balancer

• Components:
  1. Frontend IP Configuration: This is ip address of load balancer and this can be public/private (Internet facing/internal) ip address
  2. Backend pool: This is group of vms in a vmss that can serve your application
  3. Health Probes: this is a probe (check) to determine the health status of vm in vmss.
  4. Loadbalancer rules: This is used to define how incoming traffic is distributed to all instances in be pool.
  5. Inbound NAT Rule: This rule forwards incoming traffic sent to frontend ip address and port combination to specific virtual machine. By default an ssh rule is created to login into vm.
• Load Balancer SKUs:
  • Standard Load Balancer:
    • Supports upto 1000 instances
    • BE Pool: Any virtual machines or vmss in a single virtual network
    • Health Probes: TCP, HTTP, HTTPS
    • Availability Zones: Supported
    • Secure by default: All the inbound flows unless allowed by network security group are closed
  • Basic Load Balancer
    • supports upto 300 instances
    • BE Pool: Virtual machines in single availability set or virtual machine scale set
    • Health Probes: TCP, HTTP
    • Availability Zones: Not Supported
    • Open by default. Network security group is optional

Azure VMSS Steps

1. Create a VM Image
2. Creating a Azure VMSS with the VM Image created in step 1
3. Add the load balancer details
4. login into vm instance and execute the following command

stress --cpu 8 --io 4 --vm 2 --vm-bytes 128M --timeout 100m -v

5. Watch out for vmss instances for the next 5 minutes

Note:

• Install CLI and Powershell Watch Here