62 lines
1.9 KiB
Markdown
62 lines
1.9 KiB
Markdown
---
|
|
layout: "docs"
|
|
page_title: "Provisioners Without a Resource"
|
|
sidebar_current: "docs-provisioners-null-resource"
|
|
description: |-
|
|
The `null_resource` is a resource allows you to configure provisioners that
|
|
are not directly associated with a single existing resource.
|
|
---
|
|
|
|
# Provisioners Without a Resource
|
|
|
|
[null]: /docs/providers/null/resource.html
|
|
|
|
If you need to run provisioners that aren't directly associated with a specific
|
|
resource, you can associate them with a `null_resource`.
|
|
|
|
Instances of [`null_resource`][null] are treated like normal resources, but they
|
|
don't do anything. Like with any other resource, you can configure
|
|
[provisioners](/docs/provisioners/index.html) and [connection
|
|
details](/docs/provisioners/connection.html) on a `null_resource`. You can also
|
|
use its `triggers` argument and any meta-arguments to control exactly where in
|
|
the dependency graph its provisioners will run.
|
|
|
|
## Example usage
|
|
|
|
```hcl
|
|
resource "aws_instance" "cluster" {
|
|
count = 3
|
|
|
|
# ...
|
|
}
|
|
|
|
resource "null_resource" "cluster" {
|
|
# Changes to any instance of the cluster requires re-provisioning
|
|
triggers = {
|
|
cluster_instance_ids = "${join(",", aws_instance.cluster.*.id)}"
|
|
}
|
|
|
|
# Bootstrap script can run on any instance of the cluster
|
|
# So we just choose the first in this case
|
|
connection {
|
|
host = "${element(aws_instance.cluster.*.public_ip, 0)}"
|
|
}
|
|
|
|
provisioner "remote-exec" {
|
|
# Bootstrap script called with private_ip of each node in the cluster
|
|
inline = [
|
|
"bootstrap-cluster.sh ${join(" ", aws_instance.cluster.*.private_ip)}",
|
|
]
|
|
}
|
|
}
|
|
```
|
|
|
|
## Argument Reference
|
|
|
|
In addition to meta-arguments supported by all resources, `null_resource`
|
|
supports the following specific arguments:
|
|
|
|
* `triggers` - A map of values which should cause this set of provisioners to
|
|
re-run. Values are meant to be interpolated references to variables or
|
|
attributes of other resources.
|