This is the new *CloudFormation Template Reference Guide*. Please update your bookmarks and links. For help getting started with CloudFormation, see the [AWS CloudFormation User Guide](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/Welcome.html).

# AWS::AppMesh::VirtualNode VirtualNodeSpec
<a name="aws-properties-appmesh-virtualnode-virtualnodespec"></a>

An object that represents the specification of a virtual node.

## Syntax
<a name="aws-properties-appmesh-virtualnode-virtualnodespec-syntax"></a>

To declare this entity in your CloudFormation template, use the following syntax:

### JSON
<a name="aws-properties-appmesh-virtualnode-virtualnodespec-syntax.json"></a>

```
{
  "[BackendDefaults](#cfn-appmesh-virtualnode-virtualnodespec-backenddefaults)" : BackendDefaults,
  "[Backends](#cfn-appmesh-virtualnode-virtualnodespec-backends)" : [ Backend, ... ],
  "[Listeners](#cfn-appmesh-virtualnode-virtualnodespec-listeners)" : [ Listener, ... ],
  "[Logging](#cfn-appmesh-virtualnode-virtualnodespec-logging)" : Logging,
  "[ServiceDiscovery](#cfn-appmesh-virtualnode-virtualnodespec-servicediscovery)" : ServiceDiscovery
}
```

### YAML
<a name="aws-properties-appmesh-virtualnode-virtualnodespec-syntax.yaml"></a>

```
  [BackendDefaults](#cfn-appmesh-virtualnode-virtualnodespec-backenddefaults): 
    BackendDefaults
  [Backends](#cfn-appmesh-virtualnode-virtualnodespec-backends): 
    - Backend
  [Listeners](#cfn-appmesh-virtualnode-virtualnodespec-listeners): 
    - Listener
  [Logging](#cfn-appmesh-virtualnode-virtualnodespec-logging): 
    Logging
  [ServiceDiscovery](#cfn-appmesh-virtualnode-virtualnodespec-servicediscovery): 
    ServiceDiscovery
```

## Properties
<a name="aws-properties-appmesh-virtualnode-virtualnodespec-properties"></a>

`BackendDefaults`  <a name="cfn-appmesh-virtualnode-virtualnodespec-backenddefaults"></a>
A reference to an object that represents the defaults for backends.  
*Required*: No  
*Type*: [BackendDefaults](aws-properties-appmesh-virtualnode-backenddefaults.md)  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`Backends`  <a name="cfn-appmesh-virtualnode-virtualnodespec-backends"></a>
The backends that the virtual node is expected to send outbound traffic to.  
App Mesh doesn't validate the existence of those virtual services specified in backends. This is to prevent a cyclic dependency between virtual nodes and virtual services creation. Make sure the virtual service name is correct. The virtual service can be created afterwards if it doesn't already exist. 
*Required*: No  
*Type*: Array of [Backend](aws-properties-appmesh-virtualnode-backend.md)  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`Listeners`  <a name="cfn-appmesh-virtualnode-virtualnodespec-listeners"></a>
The listener that the virtual node is expected to receive inbound traffic from. You can specify one listener.  
*Required*: No  
*Type*: Array of [Listener](aws-properties-appmesh-virtualnode-listener.md)  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`Logging`  <a name="cfn-appmesh-virtualnode-virtualnodespec-logging"></a>
The inbound and outbound access logging information for the virtual node.  
*Required*: No  
*Type*: [Logging](aws-properties-appmesh-virtualnode-logging.md)  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`ServiceDiscovery`  <a name="cfn-appmesh-virtualnode-virtualnodespec-servicediscovery"></a>
The service discovery information for the virtual node. If your virtual node does not expect ingress traffic, you can omit this parameter. If you specify a `listener`, then you must specify service discovery information.  
*Required*: No  
*Type*: [ServiceDiscovery](aws-properties-appmesh-virtualnode-servicediscovery.md)  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)