79 lines
2.2 KiB
Markdown
79 lines
2.2 KiB
Markdown
---
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layout: "intro"
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page_title: "Output Variables"
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sidebar_current: "gettingstarted-outputs"
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---
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# Output Variables
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In the previous section, we introduced input variables as a way
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to parameterize Terraform configurations. In this page, we
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introduce output variables as a way to organize data to be
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easily queried and shown back to the Terraform user.
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When building potentially complex infrastructure, Terraform
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stores hundreds or thousands of attribute values for all your
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resources. But as a user of Terraform, you may only be interested
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in a few values of importance, such as a load balancer IP,
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VPN address, etc.
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Outputs are a way to tell Terraform what data is important.
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This data is outputted when `apply` is called, and can be
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queried using the `terraform output` command.
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## Defining Outputs
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Let's define an output to show us the public IP address of the
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elastic IP address that we create. Add this to any of your
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`*.tf` files:
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```
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output "ip" {
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value = "${aws_eip.ip.public_ip}"
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}
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```
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This defines an output variables named "ip". The `value` field
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specifies what the value will be, and almost always contains
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one or more interpolations, since the output data is typically
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dynamic in some form. In this case, we're outputting the
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`public_ip` attribute of the elastic IP address.
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Multiple `output` blocks can be defined to specify multiple
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output variables.
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## Viewing Outputs
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Run `terraform apply` to populate the output. This only needs
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to be done once after the output is defined. The apply output
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should change slightly. At the end you should see this:
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```
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$ terraform apply
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...
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Apply complete! Resources: 0 added, 0 changed, 0 destroyed.
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Outputs:
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ip = 50.17.232.209
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```
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`apply` highlights the outputs. You can also query the outputs
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after apply-time using `terraform output`:
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```
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$ terraform output ip
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50.17.232.209
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```
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This command is useful for scripts to extract outputs.
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## Next
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You now know how to parameterize configurations with input
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variables, and extract important data using output variables.
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Next, we're going to use provisioners to install some software
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on the instances created on top of the base AMI used.
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