How to update existing routing rule in Azure Frontdoor using PowerShell? - automation

Question

I need to update the backend pool (Maintenance) used by an existing routing rule in Azure Frontdoor to a different existing backend pool (Maintenance2). Here is the UI screen from where it can be done. Can someone advise on how to do this via PowerShell. I have tried via the cmdlets (https://learn.microsoft.com/en-us/powershell/module/az.frontdoor/set-azfrontdoor?view=azps-9.0.1 ) but unable to get the correct set of commands.
I have tried via the cmdlets (https://learn.microsoft.com/en-us/powershell/module/az.frontdoor/set-azfrontdoor?view=azps-9.0.1 ) but unable to get the correct set of commands.

Answer 1

In order to update the backend pool (Poo1) used by an existing routing rule in Azure Front Door to a different existing backend pool (Pool2).
Created a Front Door environment with backend Pools [Pool1/Pool2] which they are pointing to routing rules
Pool1 -> Rule1 and Pool2 -> Rules2
Click on Rule1
WorkAround:
Login into Powershell
tag to the current subscription where Front Door was created. using below command
az account set --subscription "******-****-****-****-*********"
Verify the Backend Pool on Front Door using this command
az network front-door backend-pool list --front-door-name "FrontDoorName" --resource-group "ResoruceGroupName"
Update Backend Pool for Rule1 from pool1 to pool2
using below command
az network front-door routing-rule update --front-door-name "Front Door Name" --name "Rule Name" --resource-group "Resource Group Name" --backend-pool "New Backend Pool"
example:
az network front-door routing-rule update --front-door-name "testfrontdoor" --name "Rule1" --resource-group "rg-testdemo" --backend-pool "pool2"
Output:
Resulted output on Front Door Rule1
Now Rule1 is points to Backend Pool "Pool2" instead of original one "Pool1".

Answer 2

Thank you Swarna. The solution provided is in CLI and the question was for powershell.
I was able to figure out how to do this in PowerShell. It requires the use of 3 Azure PS cmdlets- Get-AzFrontDoor, New-AzFrontDoorRoutingRuleObject and Set-AzFrontDoor. The way it works in the background is that when an update is performed on the Routing Rule, the routing rule is deleted and recreated with the changes. In-order to do this via PS, we have to get the existing frontdoor properties, routing rule properties and put the changes in New-AzFrontDoorRoutingRuleObject. Lastly use Set-AzFrontDoor to apply the changes to frontdoor.
$subscription='Sub1'
Select-AzSubscription $Sub1
$frontdoorName='Frontdoor1'
$resourcegroupname='fdrrg'
$MaintenanceBackPool='Maintenance2'
$PrimaryBackPool='Maintenance1'
$RoutingRuleName='Route1'
#get the current frontdoor property object
$frontdoorobj=Get-AzFrontDoor -ResourceGroupName $resourcegroupname -Name $frontdoorName
#get the Routing Rules and filter the one which needs to be modified
$RoutingRuleUpdate=$frontdoorobj.RoutingRules
$RoutingRuleUpdate2=$RoutingRuleUpdate|Where-Object {$_.Name -contains $RoutingRuleName}
#get the list of all frontendendpointIds as an array (this is required to account for more than 1 frontends/domains associated with the routing rule)
#Perform string manipulation to get the frontend/domain name from the ID
[String[]] $frontdoorHostnames=$RoutingRuleUpdate2.FrontendEndpointIds | ForEach-Object {"$PSItem" -replace '.*/'}
#get the position of the Routing Rule (to be modified) in the Routing Rules collection
$i=[array]::indexof($RoutingRuleUpdate.Name,$RoutingRuleName)
#Update the Routing Rule object with the changes needed- in this case a different backendpool
$updatedRouteObj=New-AzFrontDoorRoutingRuleObject -Name $RoutingRuleUpdate[$i].Name  -FrontDoorName $frontDoorName -ResourceGroupName $resourcegroupname -FrontendEndpointName $frontdoorHostnames -BackendPoolName $MaintenanceBackPool
$RoutingRuleUpdate[$i]=$updatedRouteObj
#Finally update the frontdoor object with the change in Routing Rule
Set-AzFrontDoor -InputObject $frontdoorobj -RoutingRule $RoutingRuleUpdate
Write-Output "Successfully Updated RoutingRule:$RoutingRuleName to backendpool:$MaintenanceBackPool"**