ardacetinkaya / terraform-azure-vm-scale-set

Basic terraform demo to develop Azure VM Scale Sets resources as backend pool for Azure Front Door.

Azure VM Scale Sets with terraform example

Basic terraform example for Azure VM Scale Sets with Azure Front Door to understand terraform properties for multi-region application.

Scenario: We have two VMs as Azure VM Scale Sets instances for our business application. Azure Front Door have a backend pool that contains these VMs. If the VM instance in one region fails, Azure Front Door handle the requests with other region. This is just a simple terraform example so some additional commands are needed to be executed in the scale set instance to do some test. In real-life scenario, pre-build VM Images with applications should be used.

Provision Azure resources

• Check terraform.tfvars file, update required Azure Service Principal values and VM info.
• Run following terraform commands in order

terraform init

terraform plan

terraform apply -auto-approve

Test

There are two VMs as jump-box per region to connect VM Scale Sets instance. From that jump-boxes, we need to RDP to VM Scale Sets instances.

In this example, IIS's default page mocks an application. So, first IIS should be installed in VM instance.

• Get scale set instances' Windows features

Get-WindowsFeature | where{$_.InstallState -eq "Installed"}

• Install Web-Server(a.k.a IIS) windows feature to VM Scale Set instance to do some test

Install-WindowsFeature -Name Web-Server -IncludeAllSubFeature -IncludeManagementTools

• Check localhost

Invoke-WebRequest -Uri 127.0.0.1 -UseBasicParsing

• Check connectivity in scale set instance

Invoke-WebRequest -Uri https://www.google.com -UseBasicParsing

• Change default IIS Page's content; this is for to observe application in other region

Set-Content -Path C:\inetpub\wwwroot\iistart.htm -Value "Hello World - Region 01/02"

• Try stoping and restarting IIS in VM Scale Sets instance per regions and observe the output.

iisreset /stop
iisreset /start

Resources

• Azure VM Scale Sets
• Azure Front Door