github.com/bengesoff/terraform@v0.3.1-0.20141018223233-b25a53629922/website/source/intro/getting-started/outputs.html.md (about)

     1  ---
     2  layout: "intro"
     3  page_title: "Output Variables"
     4  sidebar_current: "gettingstarted-outputs"
     5  ---
     6  
     7  # Output Variables
     8  
     9  In the previous section, we introduced input variables as a way
    10  to parameterize Terraform configurations. In this page, we
    11  introduce output variables as a way to organize data to be
    12  easily queried and shown back to the Terraform user.
    13  
    14  When building potentially complex infrastructure, Terraform
    15  stores hundreds or thousands of attribute values for all your
    16  resources. But as a user of Terraform, you may only be interested
    17  in a few values of importance, such as a load balancer IP,
    18  VPN address, etc.
    19  
    20  Outputs are a way to tell Terraform what data is important.
    21  This data is outputted when `apply` is called, and can be
    22  queried using the `terraform output` command.
    23  
    24  ## Defining Outputs
    25  
    26  Let's define an output to show us the public IP address of the
    27  elastic IP address that we create. Add this to any of your
    28  `*.tf` files:
    29  
    30  ```
    31  output "ip" {
    32  	value = "${aws_eip.ip.public_ip}"
    33  }
    34  ```
    35  
    36  This defines an output variables named "ip". The `value` field
    37  specifies what the value will be, and almost always contains
    38  one or more interpolations, since the output data is typically
    39  dynamic. In this case, we're outputting the
    40  `public_ip` attribute of the elastic IP address.
    41  
    42  Multiple `output` blocks can be defined to specify multiple
    43  output variables.
    44  
    45  ## Viewing Outputs
    46  
    47  Run `terraform apply` to populate the output. This only needs
    48  to be done once after the output is defined. The apply output
    49  should change slightly. At the end you should see this:
    50  
    51  ```
    52  $ terraform apply
    53  ...
    54  
    55  Apply complete! Resources: 0 added, 0 changed, 0 destroyed.
    56  
    57  Outputs:
    58  
    59    ip = 50.17.232.209
    60  ```
    61  
    62  `apply` highlights the outputs. You can also query the outputs
    63  after apply-time using `terraform output`:
    64  
    65  ```
    66  $ terraform output ip
    67  50.17.232.209
    68  ```
    69  
    70  This command is useful for scripts to extract outputs.
    71  
    72  ## Next
    73  
    74  You now know how to parameterize configurations with input
    75  variables, extract important data using output variables,
    76  and bootstrap resources using provisioners.
    77  
    78  Next, we're going to take a look at
    79  [how to use modules](/intro/getting-started/modules.html), a useful
    80  abstraction to organization and reuse Terraform configurations.