ARM Template Functions
- Functions that can be used in ARM Templates Refer Here
- You can define your own functions using User defined functions Refer
- Let use some functions. Now observe the below parameters where we have two parameters defined
"subnetcount": {
"type": "int",
"defaultValue": 4
},
"subnetnames": {
"type": "array",
"metadata": {
"description": "Names of the subnets"
},
"defaultValue": [
"ntier/web",
"ntier/app",
"ntier/db",
"ntier/management"
]
},
- subnetcount is used as a parameter in copy
{
"name": "[parameters('subnetnames')[copyIndex()]]",
"type": "Microsoft.Network/virtualNetworks/subnets",
"apiVersion": "2020-04-01",
"properties": {
"addressPrefix": "[parameters('subnetcidranges')[copyIndex()]]"
},
"copy": {
"name": "subnetcopy",
"count": "[parameters('subnetcount')]",
"mode": "serial"
},
"dependsOn": [
"[parameters('vnetname')]"
]
},
- We can eliminate this extra parameter by a very simple function length
- The specific change is
{
"name": "[parameters('subnetnames')[copyIndex()]]",
"type": "Microsoft.Network/virtualNetworks/subnets",
"apiVersion": "2020-04-01",
"properties": {
"addressPrefix": "[parameters('subnetcidranges')[copyIndex()]]"
},
"copy": {
"name": "subnetcopy",
"count": "[length(parameters('subnetcidranges'))]",
"mode": "serial"
},
"dependsOn": [
"[parameters('vnetname')]"
]
}
- With this change, the arm template look like
{
"$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
"contentVersion": "0.0.0.2",
"parameters": {
"vnetname": {
"type": "string",
"metadata": {
"description": "This is virtual network name"
},
"defaultValue": "ntier"
},
"subnetnames": {
"type": "array",
"metadata": {
"description": "Names of the subnets"
},
"defaultValue": [
"ntier/web",
"ntier/app",
"ntier/db",
"ntier/management"
]
},
"vnetaddress": {
"type": "string",
"metadata": {
"description": "description"
},
"defaultValue": "192.168.0.0/16",
"allowedValues": [
"192.168.0.0/16",
"10.0.0.0/16",
"172.16.0.0/16"
]
},
"subnetcidranges": {
"type": "array",
"metadata": {
"description": "subnet ranges"
},
"defaultValue": [
"192.168.0.0/24",
"192.168.1.0/24",
"192.168.2.0/24",
"192.168.3.0/24"
]
},
"storageaccountname": {
"type": "string",
"metadata": {
"description": "storage account name"
},
"defaultValue": "qtstoragedemoarm.com"
}
},
"resources": [
{
"name": "[parameters('vnetname')]",
"type": "Microsoft.Network/virtualNetworks",
"apiVersion": "2020-04-01",
"location": "eastus",
"properties": {
"addressSpace": {
"addressPrefixes": [
"[parameters('vnetaddress')]"
]
}
}
},
{
"name": "[parameters('subnetnames')[copyIndex()]]",
"type": "Microsoft.Network/virtualNetworks/subnets",
"apiVersion": "2020-04-01",
"properties": {
"addressPrefix": "[parameters('subnetcidranges')[copyIndex()]]"
},
"copy": {
"name": "subnetcopy",
"count": "[length(parameters('subnetcidranges'))]",
"mode": "serial"
},
"dependsOn": [
"[parameters('vnetname')]"
]
},
{
"name": "[parameters('storageaccountname')]",
"type": "Microsoft.Storage/storageAccounts",
"apiVersion": "2019-06-01",
"tags": {
"displayName": "qtstoragedemoarm"
},
"location": "eastus",
"kind": "StorageV2",
"sku": {
"name": "Standard_RAGRS",
"tier": "Standard"
},
"properties": {
"accessTier": "Hot"
}
}
]
}
- In some cases we need to refer resource related functions Refer Here
- Rather than hardcoding location we can use "location": "[resourceGroup().location]"
- Including all the above changes the template is
{
"$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
"contentVersion": "0.0.0.2",
"parameters": {
"vnetname": {
"type": "string",
"metadata": {
"description": "This is virtual network name"
},
"defaultValue": "ntier"
},
"subnetnames": {
"type": "array",
"metadata": {
"description": "Names of the subnets"
},
"defaultValue": [
"web",
"app",
"db",
"management"
]
},
"vnetaddress": {
"type": "string",
"metadata": {
"description": "description"
},
"defaultValue": "192.168.0.0/16",
"allowedValues": [
"192.168.0.0/16",
"10.0.0.0/16",
"172.16.0.0/16"
]
},
"subnetcidranges": {
"type": "array",
"metadata": {
"description": "subnet ranges"
},
"defaultValue": [
"192.168.0.0/24",
"192.168.1.0/24",
"192.168.2.0/24",
"192.168.3.0/24"
]
},
"storageaccountname": {
"type": "string",
"metadata": {
"description": "storage account name"
},
"defaultValue": "qtstoragedemoarm.com"
}
},
"resources": [
{
"name": "[parameters('vnetname')]",
"type": "Microsoft.Network/virtualNetworks",
"apiVersion": "2020-04-01",
"location": "[resourceGroup().location]",
"properties": {
"addressSpace": {
"addressPrefixes": [
"[parameters('vnetaddress')]"
]
}
}
},
{
"name": "[concat(parameters('vnetname'),'/',parameters('subnetnames')[copyIndex()])]",
"type": "Microsoft.Network/virtualNetworks/subnets",
"apiVersion": "2020-04-01",
"properties": {
"addressPrefix": "[parameters('subnetcidranges')[copyIndex()]]"
},
"copy": {
"name": "subnetcopy",
"count": "[length(parameters('subnetcidranges'))]",
"mode": "serial"
},
"dependsOn": [
"[parameters('vnetname')]"
]
},
{
"name": "[parameters('storageaccountname')]",
"type": "Microsoft.Storage/storageAccounts",
"apiVersion": "2019-06-01",
"tags": {
"displayName": "qtstoragedemoarm"
},
"location": "[resourceGroup().location]",
"kind": "StorageV2",
"sku": {
"name": "Standard_RAGRS",
"tier": "Standard"
},
"properties": {
"accessTier": "Hot"
}
}
]
}
Add variables to your ARM template
- Variables are values which are not provided by user executing the ARM template rather they are values which can be calculated with in template Refer Here
- Parameters are values which user has to provide and cannot be computed in a template and Variables are values which can be computed in a template
[variable('location')]
- Now lets add vm creation
-
There are predefined templates from microsoft available over here
-
For configuring Azure CLI and Powershell Watch Here
-
Deploying Template from powershell Refer Here
-
Deploying Template from cli Refer Here
-
Outputs in ARM Templates Refer Here
Other Template Deployments for reusability
- Nested Templates:
- With in your template you define some other template Refer Here
- Linked Templates
- With in your template you link of the other template Refer Here
Azure Blueprints
- Deploy applications in azure /any cloud we need to
- Role assignments (IAM)
- Follow some policies (Azure Policy)
- Create infrastructure ( ARM Template)
- Resource Groups
- Azure has a service which exactly does this and is called as Azure Blue print
- Lets create a azure blue print
Azure Data Migration
- Azure has created a very interesting documentation around database migrations Refer Here
VMWare to Azure
Exercise:
- Write an ARM Template to Create Virtual Machine Scale Set in Azure Refer Here
