terraform/website/docs/language/meta-arguments/lifecycle.html.md

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---
layout: "language"
page_title: "The lifecycle Meta-Argument - Configuration Language"
---
# The `lifecycle` Meta-Argument
> **Hands-on:** Try the [Lifecycle Management](https://learn.hashicorp.com/tutorials/terraform/resource-lifecycle?utm_source=WEBSITE&utm_medium=WEB_IO&utm_offer=ARTICLE_PAGE&utm_content=DOCS) tutorial on HashiCorp Learn.
The general lifecycle for resources is described in the
[Resource Behavior](/docs/language/resources/behavior.html) page. Some details of
that behavior can be customized using the special nested `lifecycle` block
within a resource block body:
```hcl
resource "azurerm_resource_group" "example" {
# ...
lifecycle {
create_before_destroy = true
}
}
```
## Syntax and Arguments
`lifecycle` is a nested block that can appear within a resource block.
The `lifecycle` block and its contents are meta-arguments, available
for all `resource` blocks regardless of type.
The following arguments can be used within a `lifecycle` block:
* `create_before_destroy` (bool) - By default, when Terraform must change
a resource argument that cannot be updated in-place due to
remote API limitations, Terraform will instead destroy the existing object
and then create a new replacement object with the new configured arguments.
The `create_before_destroy` meta-argument changes this behavior so that
the new replacement object is created _first,_ and the prior object
is destroyed after the replacement is created.
This is an opt-in behavior because many remote object types have unique
name requirements or other constraints that must be accommodated for
both a new and an old object to exist concurrently. Some resource types
offer special options to append a random suffix onto each object name to
avoid collisions, for example. Terraform CLI cannot automatically activate
such features, so you must understand the constraints for each resource
type before using `create_before_destroy` with it.
* `prevent_destroy` (bool) - This meta-argument, when set to `true`, will
cause Terraform to reject with an error any plan that would destroy the
infrastructure object associated with the resource, as long as the argument
remains present in the configuration.
This can be used as a measure of safety against the accidental replacement
of objects that may be costly to reproduce, such as database instances.
However, it will make certain configuration changes impossible to apply,
and will prevent the use of the `terraform destroy` command once such
objects are created, and so this option should be used sparingly.
Since this argument must be present in configuration for the protection to
apply, note that this setting does not prevent the remote object from
being destroyed if the `resource` block were removed from configuration
entirely: in that case, the `prevent_destroy` setting is removed along
with it, and so Terraform will allow the destroy operation to succeed.
* `ignore_changes` (list of attribute names) - By default, Terraform detects
any difference in the current settings of a real infrastructure object
and plans to update the remote object to match configuration.
The `ignore_changes` feature is intended to be used when a resource is
created with references to data that may change in the future, but should
not affect said resource after its creation. In some rare cases, settings
of a remote object are modified by processes outside of Terraform, which
Terraform would then attempt to "fix" on the next run. In order to make
Terraform share management responsibilities of a single object with a
separate process, the `ignore_changes` meta-argument specifies resource
attributes that Terraform should ignore when planning updates to the
associated remote object.
The arguments corresponding to the given attribute names are considered
when planning a _create_ operation, but are ignored when planning an
_update_. The arguments are the relative address of the attributes in the
resource. Map and list elements can be referenced using index notation,
like `tags["Name"]` and `list[0]` respectively.
```hcl
resource "aws_instance" "example" {
# ...
lifecycle {
ignore_changes = [
# Ignore changes to tags, e.g. because a management agent
# updates these based on some ruleset managed elsewhere.
tags,
]
}
}
```
Instead of a list, the special keyword `all` may be used to instruct
Terraform to ignore _all_ attributes, which means that Terraform can
create and destroy the remote object but will never propose updates to it.
Only attributes defined by the resource type can be ignored.
`ignore_changes` cannot be applied to itself or to any other meta-arguments.
## Literal Values Only
The `lifecycle` settings all affect how Terraform constructs and traverses
the dependency graph. As a result, only literal values can be used because
the processing happens too early for arbitrary expression evaluation.