opentofu/website/docs/provisioners/local-exec.html.markdown
Martin Atkins e0d72930fa website: Warn against using provisioners
For a long time now we've been advising against the use of provisioners,
but our documentation for them is pretty prominent on the website in
comparision to the better alternatives, and so it's little surprise that
many users end up making significant use of them.

Although in the longer term a change to our information architecture would
probably address this even better, this is an attempt to be explicit about
the downsides of using provisioners and to prominently describe the
alternatives that are available for common use-cases, along with some
reasons why we consider them to be better.

I took the unusual step here of directly linking to specific provider
documentation pages about the alternatives, even though we normally try
to keep the core documentation provider-agnostic, because otherwise that
information tends to be rather buried in the provider documentation and
thus the reader would be reasonable to use provisioners just because we're
not giving specific enough alternative recommendations.
2019-09-05 16:09:06 -07:00

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---
layout: "docs"
page_title: "Provisioner: local-exec"
sidebar_current: "docs-provisioners-local"
description: |-
The `local-exec` provisioner invokes a local executable after a resource is created. This invokes a process on the machine running Terraform, not on the resource. See the `remote-exec` provisioner to run commands on the resource.
---
# local-exec Provisioner
The `local-exec` provisioner invokes a local executable after a resource is
created. This invokes a process on the machine running Terraform, not on the
resource. See the `remote-exec`
[provisioner](/docs/provisioners/remote-exec.html) to run commands on the
resource.
Note that even though the resource will be fully created when the provisioner is
run, there is no guarantee that it will be in an operable state - for example
system services such as `sshd` may not be started yet on compute resources.
-> **Note:** Provisioners should only be used as a last resort. For most
common situations there are better alternatives. For more information, see
[the main Provisioners page](./).
## Example usage
```hcl
resource "aws_instance" "web" {
# ...
provisioner "local-exec" {
command = "echo ${aws_instance.web.private_ip} >> private_ips.txt"
}
}
```
## Argument Reference
The following arguments are supported:
* `command` - (Required) This is the command to execute. It can be provided
as a relative path to the current working directory or as an absolute path.
It is evaluated in a shell, and can use environment variables or Terraform
variables.
* `working_dir` - (Optional) If provided, specifies the working directory where
`command` will be executed. It can be provided as as a relative path to the
current working directory or as an absolute path. The directory must exist.
* `interpreter` - (Optional) If provided, this is a list of interpreter
arguments used to execute the command. The first argument is the
interpreter itself. It can be provided as a relative path to the current
working directory or as an absolute path. The remaining arguments are
appended prior to the command. This allows building command lines of the
form "/bin/bash", "-c", "echo foo". If `interpreter` is unspecified,
sensible defaults will be chosen based on the system OS.
* `environment` - (Optional) block of key value pairs representing the
environment of the executed command. inherits the current process environment.
### Interpreter Examples
```hcl
resource "null_resource" "example1" {
provisioner "local-exec" {
command = "open WFH, '>completed.txt' and print WFH scalar localtime"
interpreter = ["perl", "-e"]
}
}
```
```hcl
resource "null_resource" "example2" {
provisioner "local-exec" {
command = "Get-Date > completed.txt"
interpreter = ["PowerShell", "-Command"]
}
}
```
```hcl
resource "aws_instance" "web" {
# ...
provisioner "local-exec" {
command = "echo $FOO $BAR $BAZ >> env_vars.txt"
environment = {
FOO = "bar"
BAR = 1
BAZ = "true"
}
}
}
```