ARM templates to deploy a single hub vnet with large number of spoke vnets in peering.
List of files:
| Name | Description |
|---|---|
| vnets.json | ARM template to create hub vnet, spoke vnets and connect hub-spoke in peering |
| vnets.ps1 | powershell script to deploy vnets.json |
| vnets-peering.json | ARM template to create vnet peering between hub and spoke vnets |
| vnets-peering.ps1 | powershell script to deploy vnets-peering.json |
Run the scripts in sequence:
- first step: run the vnets.ps1 to deploy hub and spoke vnets
- second step: run the vnets-peering.ps1 to create the peering between hub and spoke vnets
vnets-peering.ps1 will fail if the hub and spoke vnets are not already deployed.
NOTE the powershell scripts read get the values of some variables from the file init.txt
$rgName: name of resource group
$RGTagExpireDate: set an expiration date in the tag value
$RGTagContact: set a contact in the tag value
$RGTagNinja: set the alias in the tag value
$RGTagUsage: purpose of deployment in the tag value
The ARM template supports automatic creation of spoke vnets with address space by a loop.
Each spoke vnet has an address space /24 as below:
First-Octet.SecondOctet.ThirdOctet.0/24- First-Octet: it is fixed digit
- SecondOctet: it starts from a starting integer value specified in the ARM template. The value of SecondOctet increases from the starting value only when the ThirdOctet overcome 255
- ThirdOctet: the counter on this octet start from 0 to 255. For number of spoke above 255, the value of second octet restart from zero
The logic of assigment of SecondOctet and ThirdOctet in address space of spoke vnets is implemented through the functions:
string( add(variables('secondOctet'),div(copyIndex(),255)) )
string( add(variables('thirdOctet'),mod(copyIndex(),255)) )- add: returns the sum of the two provided integers.
- div: returns the integer division of the two provided integers.
- mod: returns the remainder of the integer division using the two provided integers.
NOTE
The cycles in ARM template to create the vnet peering are established sequentially by "batchSize": 1 to avoid deployment collisions and failure. Due to sequential operations the execution of the vnets-peering.json takes longer runtime. The runtime to create 400 vnet peering takes more or less 3 hours.
The ARM template is able to deploy max 400 spoke vnets. If you set a with high number of spoke vnets, you might get the error message:
Error: Code=InvalidTemplate; Message=Deployment template validation failed: 'The number of template resources limit exceeded. Limit: '800'