61 lines
1.8 KiB
Markdown
61 lines
1.8 KiB
Markdown
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---
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layout: "docs"
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page_title: "Provisioners: null_resource"
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sidebar_current: "docs-provisioners-null-resource"
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description: |-
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The `null_resource` is a resource allows you to configure provisioners that
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are not directly associated with a single exiting resource.
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---
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# null\_resource
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The `null_resource` is a resource that allows you to configure provisioners
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that are not directly associated with a single existing resource.
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A `null_resource` behaves exactly like any other resource, so you configure
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[provisioners](/docs/provisioners/index.html), [connection
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details](/docs/provisioners/connection.html), and other meta-parameters in the
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same way you would on any other resource.
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This allows fine-grained control over when provisioners run in the dependency
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graph.
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## Example usage
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```
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# Bootstrap a cluster after all its instances are up
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resource "aws_instance" "cluster" {
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count = 3
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// ...
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}
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resource "null_resource" "cluster" {
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# Changes to any instance of the cluster requires re-provisioning
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triggers {
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cluster_instance_ids = "${join(",", aws_instance.cluster.*.id)}"
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}
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# Bootstrap script can run on any instance of the cluster
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# So we just choose the first in this case
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connection {
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host = "${element(aws_instance.cluster.*.public_ip, 0)}"
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}
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provisioner "remote-exec" {
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# Bootstrap script called with private_ip of each node in the clutser
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inline = [
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"bootstrap-cluster.sh ${join(" ", aws_instance.cluster.*.private_ip}"
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]
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}
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}
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```
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## Argument Reference
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In addition to all the resource configuration available, `null_resource` supports the following specific configuration options:
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* `triggers` - A mapping of values which should trigger a rerun of this set of
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provisioners. Values are meant to be interpolated references to variables or
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attributes of other resources.
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