Terraform loads all configuration files within a directory and appends them together. Terraform also has a concept of overrides, a way to create files that are loaded last and merged into your configuration, rather than appended.
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# Overrides
Terraform loads all configuration files within a directory and
appends them together. Terraform also has a concept of _overrides_,
a way to create files that are loaded last and _merged_ into your
configuration, rather than appended.
Overrides have a few use cases:
* Machines (tools) can create overrides to modify Terraform
behavior without having to edit the Terraform configuration
tailored to human readability.
* Temporary modifications can be made to Terraform configurations
without having to modify the configuration itself.
Overrides names must be `override` or end in `_override`, excluding
the extension. Examples of valid override files are `override.tf`,
`override.tf.json`, `temp_override.tf`.
Override files are loaded last in alphabetical order.
Override files can be in Terraform syntax or JSON, just like non-override
Terraform configurations.
## Example
If you have a Terraform configuration `example.tf` with the contents:
```hcl
resource "aws_instance" "web" {
ami = "ami-408c7f28"
}
```
And you created a file `override.tf` with the contents:
```hcl
resource "aws_instance" "web" {
ami = "foo"
}
```
Then the AMI for the one resource will be replaced with "foo". Note
that the override syntax can be Terraform syntax or JSON. You can
