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Set name and type for child resources

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Child resources are resources that exist only within the context of another resource. For example, a virtual machine extension can't exist without a virtual machine. The extension resource is a child of the virtual machine.

Each parent resource accepts only certain resource types as child resources. The resource type for the child resource includes the resource type for the parent resource. For example, Microsoft.Web/sites/config and Microsoft.Web/sites/extensions are both child resources of the Microsoft.Web/sites. The accepted resource types are specified in the template schema of the parent resource.

In an Azure Resource Manager template (ARM template), you can specify the child resource either within the parent resource or outside of the parent resource. The values you provide for the resource name and resource type vary based on whether the child resource is defined inside or outside of the parent resource.

Tip

We recommend Bicep because it offers the same capabilities as ARM templates and the syntax is easier to use. To learn more, see child resources.

Within parent resource

The following example shows the child resource included within the resources property of the parent resource.

"resources": [
  {
    <parent-resource>
    "resources": [
      <child-resource>
    ]
  }
]

Child resources can only be defined five levels deep.

When defined within the parent resource type, you format the type and name values as a single segment without slashes.

"type": "{child-resource-type}",
"name": "{child-resource-name}",

The following example shows a virtual network and with a subnet. Notice that the subnet is included within the resources array for the virtual network. The name is set to Subnet1 and the type is set to subnets. The child resource is marked as dependent on the parent resource because the parent resource must exist before the child resource can be deployed.

"resources": [
  {
    "type": "Microsoft.Network/virtualNetworks",
    "apiVersion": "2022-11-01",
    "name": "VNet1",
    "location": "[parameters('location')]",
    "properties": {
      "addressSpace": {
        "addressPrefixes": [
          "10.0.0.0/16"
        ]
      }
    },
    "resources": [
      {
        "type": "subnets",
        "apiVersion": "2022-11-01",
        "name": "Subnet1",
        "dependsOn": [
          "VNet1"
        ],
        "properties": {
          "addressPrefix": "10.0.0.0/24"
        }
      }
    ]
  }
]

The full resource type is still Microsoft.Network/virtualNetworks/subnets. You don't provide Microsoft.Network/virtualNetworks/ because it's assumed from the parent resource type.

The child resource name is set to Subnet1 but the full name includes the parent name. You don't provide VNet1 because it's assumed from the parent resource.

Outside parent resource

The following example shows the child resource outside of the parent resource. You might use this approach if the parent resource isn't deployed in the same template, or if want to use copy to create more than one child resource.

"resources": [
  {
    <parent-resource>
  },
  {
    <child-resource>
  }
]

When defined outside of the parent resource, you format the type and name values with slashes to include the parent type and name.

"type": "{resource-provider-namespace}/{parent-resource-type}/{child-resource-type}",
"name": "{parent-resource-name}/{child-resource-name}",

The following example shows a virtual network and subnet that are both defined at the root level. Notice that the subnet isn't included within the resources array for the virtual network. The name is set to VNet1/Subnet1 and the type is set to Microsoft.Network/virtualNetworks/subnets. The child resource is marked as dependent on the parent resource because the parent resource must exist before the child resource can be deployed.

"resources": [
  {
    "type": "Microsoft.Network/virtualNetworks",
    "apiVersion": "2022-11-01",
    "name": "VNet1",
    "location": "[parameters('location')]",
    "properties": {
      "addressSpace": {
        "addressPrefixes": [
          "10.0.0.0/16"
        ]
      }
    }
  },
  {
    "type": "Microsoft.Network/virtualNetworks/subnets",
    "apiVersion": "2022-11-01",
    "name": "VNet1/Subnet1",
    "dependsOn": [
      "VNet1"
    ],
    "properties": {
      "addressPrefix": "10.0.0.0/24"
    }
  }
]

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