What does "hidden-link:" mean in Azure Resource Manager Tags

Question

I exported an Azure Resource Manager JSON template from my resource group on Azure. I see a bunch of tags in the generated file like:

"tags": {
    "hidden-link:/subscriptions/[my-subscription-id-here]/resourceGroups/[my-resource-group]/providers/Microsoft.Sql/servers/[my-database-server-name]/databases/[my-database-name]": "Resource"
},

The only documentation I can find on it is from Using tags to organize your Azure resources, which says:

You may see tags that start with "hidden-" and "link:". These are internal tags, which you should ignore and avoid changing.

The problem is that I'm going to be deploying this resource template to a completely different subscription than the one whose ID is hard-coded into the tag. Any meaning that the hard-coded subscription id has in this tag will be lost. Can I safely remove this tag? What does it mean, and how is it used once deployed?

Klepto Klepto · Accepted Answer · 2019-02-11T13:55:26

Just to help stop anyone else from wasting a couple of hours in frustration:

Don't remove these tags from your generated ARM template for web tests in Application Insights.

I was wondering if I really needed these tags since they were very specific to the resource that I used to create the template from. Reading this answer I figured that it wasn't necessary so I removed them and promptly forgot about removing them.

The deployment then started failing with the very descriptive error:

{
 "code": "BadRequest",
 "message": "{
   "code": "BadRequest",
   "message": "Bad Request\",
   "innererror": 
    {
       "diagnosticcontext": "d657bd3b-6b5f-4b24-8963-c2e9ac76a65b\",
       "time": "2019-02-05T13:37:23.6473698Z"
    }
}

Putting the "hidden-links" back in seems to fix the issue.

An alternative that makes the script a bit more reusable is specifying the "hidden-link" as follows:

"tags": { "[concat('hidden-link:', resourceId('Microsoft.Insights/components', parameters('appInsightsName')))]": "Resource" }

Where applicationInsightName is a variable containing the name of the ApplicationInsight instance

What does "hidden-link:" mean in Azure Resource Manager Tags

3 Answers