You can use *references* to define the properties of your configuration or
templates instead of directly providing values.

With references, you can access properties that are not defined until the
resource is created. For example, when you define a virtual machine (VM) in your
configuration, you do not know its IP address. However, you can create a
reference to the IP address.

In this step, you will examine an updated `two-vms.yaml` that contains a
network, as well as VM instances that reference the network.

## Opening the new configuration

Open a new `two-vms.yaml`, which defines a network called `a-new-network`:

    cd deploymentmanager-samples/examples/v2/step_by_step_guide/step4_use_references

    nano two-vms.yaml  # use your preferred text editor

### Viewing the references to the network

In the `properties` section of both your virtual machine instances, note that
the value of `network` have a reference to the new network's `selfLink`
property, so that the network interface property looks like this:

    networkInterfaces:
    - network: $(ref.a-new-network.selfLink)

## Deploying the configuration

In the sample, replace all instances of <var translate="no">MY_PROJECT</var>
with your project ID, then deploy your configuration with the following command:

    gcloud deployment-manager deployments create deployment-with-references --config two-vms.yaml

To view your deployment, use the following command:

    gcloud deployment-manager deployments describe deployment-with-references

## Looking ahead: templates and variables

To maximize efficiency when you're building complex configurations, follow best
practices such as using variables and templates.

In the next step, you will learn about templates and how they enable flexible,
dynamic configurations.

## Deleting your deployment

Once again, we recommend that you delete the deployment to avoid charges. You
don't need this deployment for the next step. Run the following command to
delete the deployment:

    gcloud deployment-manager deployments delete deployment-with-references