Scaling Azure VMs

Vertical Scaling

• Vertical Scaling requires restart of the machine, which means downtime.
• Vertical Scaling can be done by clicking on sizes blade and selecting the new size.
• In Azure you can increase the size as well as decrease the size

Horizontal Scaling

• Horizontal scaling generally speaks about increasing machines so that load can be shared.
• In Azure increasing number of VMs (Scale out) and Decreasing VMS (Scale in) are supported by Virtual Machine Scale Sets

Virtual Machine Scale Sets(VMSS)

• All the VMS in VMSS should have same VM Image
• Ensure Transactional Data is not stored locally in the VM, rather in some external system like database
• When should i Scale out and when should i Scale in
  • This numbers (triggers) are defined only after benchmarking/performance testing
• What are the different Metrics which i can use as Triggers
  • CPU
  • Memory
  • Network
  • Disk

VMSS Creation Considerations

• Create a VM Image for the application which you want to scale
• Generally it is a good idea to have vm image created automatically, whenever you have a release.
• Always have atleast one VM image which is working and then try new releases.
• Ensure you have data on when to Scale in and Scale out.

VMSS Preparation

Linux

• Create a VM Image of a Linux Server.
• Create a VM with Ubuntu 16/18 (B1S).
• SSH into VM and Execute the following commands. Refer Here

sudo apt-get update
sudo apt-get install apache2 -y
sudo apt-get install php libapache2-mod-php php-mcrypt php-mysql
sudo apt-get install php-cli
create a file in /var/www/html/info.php with content
<?php
phpinfo();
?>

sudo apt-get install stress -y

• Create a VM Image for this VM.