Define an environment variable for the instance deployed by this build step. The variable will hold the instance ID.

Additional instance properties will also be available via other environment variables that have the defined variable as prefix of their name. For example, if INSTANCE is specified for this field then the following environment variables are available:
  INSTANCE - ID of the deployed instance
  INSTANCE_URL - URL of the deployed instance
  INSTANCE_SERVICE_ID - service ID of the deployed instance
  INSTANCE_TAGS - comma-separate list of tags of the deployed instance
If 1 is specified for Number of Instances then the following environment variables are available:
  INSTANCE_MACHINE_NAME - VM name of the deployed instance
  INSTANCE_PUBLIC_ADDRESS - VM public address of the deployed instance
  INSTANCE_PRIVATE_ADDRESS - VM private address of the deployed instance
If Number of Instances is greater than 1, the following environment variable are available:
  INSTANCE_MACHINE_NAMES - space-separate list of VM names
  INSTANCE_PUBLIC_ADDRESSES - space-separate list of public addresses of the VMs
  INSTANCE_PRIVATE_ADDRESSES - space-separate list of private addresses of the VMs