Adding new rule in exisitng app gateway through powershall

Question

Hi,

I have an existing app gateway has 4 path based rule setup. I need to add new entry in app gateway through powershell, I have used following commands but after running it removes all existing entries and adds only new rule (overrides all 4 rules and add only new entry):

$appgw = Set-AzApplicationGatewayUrlPathMapConfig -ApplicationGateway $appgw -Name "pathBasedRule" -PathRules $myPathRule -DefaultBackendAddressPool $backendPool -DefaultBackendHttpSettings $backendPoolSetting

Set-AzApplicationGateway -ApplicationGateway $appgw

I couldn't find any power shell command where I can fetch all 4 rules then I will add 1 new rule, so that
my app gateway will have 5 rules after running. how can I do that through PS?

Thnaks

Answer 1

I have found the solution through ARM template. If anyone facing similar kind of issue here are the details:

As I didn't find any ps command to add new rule in existing path based rule, we can add completely new rule using Add-AzApplicationGatewayUrlPathMapConfig but I want to just add new path based condition. below is json template that has 2 rules:

    "urlPathMaps": [
      {
        "name": "urlPathMap1",
        "properties": {
          "defaultBackendAddressPool": {
            "id": "[concat(variables('applicationGatewayID'), '/backendAddressPools/appGatewayBackendPoolDefault')]"
          },
          "defaultBackendHttpSettings": {
            "id": "[concat(variables('applicationGatewayID'), '/backendHttpSettingsCollection/appGatewayBackendHttpSettings')]"
          },
          "pathRules": [
            {
              "name": "pathRule1",
              "properties": {
                "paths": [
                  "[parameters('pathMatch1')]"
                ],
                "backendAddressPool": {
                  "id": "[concat(variables('applicationGatewayID'), '/backendAddressPools/appGatewayBackendPool1')]"
                },
                "backendHttpSettings": {
                  "id": "[concat(variables('applicationGatewayID'), '/backendHttpSettingsCollection/appGatewayBackendHttpSettings')]"
                }
              }
            },
            {
              "name": "pathRule2",
              "properties": {
                "paths": [
                  "[parameters('pathMatch2')]"
                ],
                "backendAddressPool": {
                  "id": "[concat(variables('applicationGatewayID'), '/backendAddressPools/appGatewayBackendPool2')]"
                },
                "backendHttpSettings": {
                  "id": "[concat(variables('applicationGatewayID'), '/backendHttpSettingsCollection/appGatewayBackendHttpSettings')]"
                }
              }
            }
          ]
        }
      }
    ]

we can add another rule to add new path condition in existing app gateway, here is github link for complete sample template.

https://github.com/Azure/azure-quickstart-templates/blob/master/201-application-gateway-url-path-based-routing/azuredeploy.json

Hope this will help someone.

Thanks.

Answer 2

Greetings,

You need to use "Add" instead of "Set" here in order to avoid overriding of previous rules. The Add-AzApplicationGatewayUrlPathMapConfig cmdlet adds an array of URL path mappings to a back end server pool. Here is an example script for your reference,

$appgw = Add-AzApplicationGatewayUrlPathMapConfig -ApplicationGateway $appgw -Name "APPGW-Name" -PathRules $pathRule - DefaultBackendAddressPool $pool -DefaultBackendHttpSettings $poolSettings


$appgw = Set-AzApplicationGateway -ApplicationGateway $appgw

This will allow you to add the new rules with out overriding the previous one.

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