ARM Templates

ARM (Azure Resource Manager) Templates are JSON files build in a specific schema that allow to build Azure resources using code
It is Microsoft’s IaC (Infrastructure as Code) tooling
They allow to define and build resources in consistent manner which in turn lowers administrative effort

Deployment Modes

Complete: Delete all the resources in RG that are not in ARM template and deploy resources
Incremental: Ignore resources in RG that are not mentioned in template and update the properties of other properties as defined in template

Nested and Linked Template

Nested and Linked Templates allow to modularize ARM Templates
When using them only Incremental Deployment is supported

Nested Template can defined inside in the template: {} node in template similarly linked templates are always defined inside the templateLink: {} node

When using Linked Template the template files need to be hosted in a globally location like like Blob Storage, GitHub which can be accessed by Resource Manager, it cannot be deployed from local machine

Commands

# Resource Group Level Deployments
New-AzResourceGroupDeployment ` 
	-ResourceGroupName <resource-group-name> `
	-TemplateFile <path-to-template> `
	-TemplateParameterFile <path-to-parameters>
 
# Subscription Level Deployment
New-AzSubscriptionDeployment `
	-Location <location> `
	-TemplateFile <path-to-template>

For deploying ARM Templates using Azure CLI and using Azure Pipelines we need to create a Service Principal

# Create a Service Principal
az ad sp create-for-rbac 
	--name myServicePrincipalName \
	--role contributer \
	--scopes /subscriptions/subscriptionID/resourceGroups/resourceGroupName
 
# Create Resource Group Level Deployment
az deployment group create \
	--resource-group <resource-group-name> \
	--template-file <path-to-template>
	--parameters <path-to-parameters>
 
# Create Subscription Level Deployment
az deployment sub create \
	--location <location> \
	--template-file <path-to-template>