Components to be understood in/around VMSS

• Backend Pool: Backend pool to a Loadbalancer is the vm’s or the whole VMSS which has to be load balanced
• Health Probe: Load Balancer keeps track of healhy machines in VMSS using health probes. Health Probes are of two types
  • TCP Probe
  • HTTP Probe
• Load Balancing Rules: Load balancing rules are use to load balance users request to load balancer
• Inbound NAT: Is used to get into the other ports of the VMSS
• YOu can login into virtual machine of the VMSS using one one of inbound nat rule
• Now login into vm using the following command

ssh -p 50000 <username>@<lbip>

# ssh -p 50000 qtdevops@40.57.87.98

• NOw lets generate artificial cpu load using stress tool

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

• Using htop the artifical load on cpu inside the vm looks like

• Watch CPU Average on the VMSS Overview

• As CPU Load increase VMs inside VMSS increase

• Now navigate to http://<lbip>/info.php and refresh twice

• Now if you stop the artificial load, vmsize will fall back to minimum(1)