Azure ARM templates - using the output of other deployments

Question

What I am interested in is reading the output parameters of another deployment in a different resource group. My ARM templates are something like:

1. platform.jso

Answer 1

I know this is an old question but for others who come along, as of 03/12/18 you can definitely do this.

You need to ensure your output is formatted as per the Microsoft documentation for output variables which broadly has the format

"outputs": {
  "resourceID": {
    "type": "string",
    "value": "[resourceId('Microsoft.Network/publicIPAddresses', parameters('publicIPAddresses_name'))]"
  }
}

You can then use these outputs in your templates by referencing the deployment using a resource reference which has the format

reference(resourceName or resourceIdentifier, [apiVersion], ['Full'])

Note that you will need to provide the api version, as the deployment may use a different api version to the one your parent template uses.

Your reference would then look something like the following

{
  "comments": "This would have an output named myOutput you want to use",
  "apiVersion": "2017-05-10",
  "type": "Microsoft.Resources/deployments",
  "name": "my-deployment",
  "resourceGroup": "...",
  "properties": {
    "mode": "Incremental",
    "templateLink": {
      "uri": "...",
      "contentVersion": "1.0.0.0"
    },
    "parameters": { }
},
{
  "comments": "This makes use of myOutput from my-deployment",
  "apiVersion": "2017-05-10",
  "type": "Microsoft.Resources/deployments",
  "name": "my-dependent-deployment",
  "properties": {
    "mode": "Incremental",
    "templateLink": {
      "uri": "...",
      "contentVersion": "1.0.0.0"
    },
    "parameters": {
      "myValueFromAnotherDeployment": { "value": "[reference('my-deployment', '2017-05-10').outputs.myOutput.value]" }
    }
  }
}

Note the slightly awkward "repackaging" of the value, where we use myOutput.value as the input to the dependent deployment, and put that in an object with the key "value": "....". This is because ARM parameters must have a 'value' property in order to be valid.

You'll get invalid template errors if you try to use the output directly (because output variables have a 'type' and this is not an allowed key in a parameter). That's why you need to get the value property and then put it back into the value in downstream templates.