403 lines
19 KiB
Plaintext
403 lines
19 KiB
Plaintext
---
|
|
page_title: 'Command: plan'
|
|
description: >-
|
|
The terraform plan command creates an execution plan with a preview of the
|
|
changes that Terraform will make to your infrastructure.
|
|
---
|
|
|
|
# Command: plan
|
|
|
|
The `terraform plan` command creates an execution plan, which lets you preview
|
|
the changes that Terraform plans to make to your infrastructure. By default,
|
|
when Terraform creates a plan it:
|
|
|
|
* Reads the current state of any already-existing remote objects to make sure
|
|
that the Terraform state is up-to-date.
|
|
* Compares the current configuration to the prior state and noting any
|
|
differences.
|
|
* Proposes a set of change actions that should, if applied, make the remote
|
|
objects match the configuration.
|
|
|
|
> **Hands-on:** Try the [Terraform: Get Started](https://learn.hashicorp.com/collections/terraform/aws-get-started?utm_source=WEBSITE&utm_medium=WEB_IO&utm_offer=ARTICLE_PAGE&utm_content=DOCS) collection on HashiCorp Learn.
|
|
|
|
The plan command alone will not actually carry out the proposed changes, and
|
|
so you can use this command to check whether the proposed changes match what
|
|
you expected before you apply the changes or share your changes with your
|
|
team for broader review.
|
|
|
|
If Terraform detects that no changes are needed to resource instances or to
|
|
root module output values, `terraform plan` will report that no actions need
|
|
to be taken.
|
|
|
|
If you are using Terraform directly in an interactive terminal and you expect
|
|
to apply the changes Terraform proposes, you can alternatively run
|
|
[`terraform apply`](/cli/commands/apply) directly. By default, the "apply" command
|
|
automatically generates a new plan and prompts for you to approve it.
|
|
|
|
You can use the optional `-out=FILE` option to save the generated plan to a
|
|
file on disk, which you can later execute by passing the file to
|
|
[`terraform apply`](/cli/commands/apply) as an extra argument. This two-step workflow
|
|
is primarily intended for when
|
|
[running Terraform in automation](https://learn.hashicorp.com/tutorials/terraform/automate-terraform?in=terraform/automation&utm_source=WEBSITE&utm_medium=WEB_IO&utm_offer=ARTICLE_PAGE&utm_content=DOCS).
|
|
|
|
If you run `terraform plan` without the `-out=FILE` option then it will create
|
|
a _speculative plan_, which is a description of the effect of the plan but
|
|
without any intent to actually apply it.
|
|
|
|
In teams that use a version control and code review workflow for making changes
|
|
to real infrastructure, developers can use speculative plans to verify the
|
|
effect of their changes before submitting them for code review. However, it's
|
|
important to consider that other changes made to the target system in the
|
|
meantime might cause the final effect of a configuration change to be different
|
|
than what an earlier speculative plan indicated, so you should always re-check
|
|
the final non-speculative plan before applying to make sure that it still
|
|
matches your intent.
|
|
|
|
## Usage
|
|
|
|
Usage: `terraform plan [options]`
|
|
|
|
The `plan` subcommand looks in the current working directory for the root module
|
|
configuration.
|
|
|
|
Because the plan command is one of the main commands of Terraform, it has
|
|
a variety of different options, described in the following sections. However,
|
|
most of the time you should not need to set any of these options, because
|
|
a Terraform configuration should typically be designed to work with no special
|
|
additional options for routine work.
|
|
|
|
The remaining sections on this page describe the various options:
|
|
|
|
* **[Planning Modes](#planning-modes)**: There are some special alternative
|
|
planning modes that you can use for some special situations where your goal
|
|
is not just to change the remote system to match your configuration.
|
|
* **[Planning Options](#planning-options)**: Alongside the special planning
|
|
modes, there are also some options you can set in order to customize the
|
|
planning process for unusual needs.
|
|
* **[Resource Targeting](#resource-targeting)** is one particular
|
|
special planning option that has some important caveats associated
|
|
with it.
|
|
* **[Other Options](#other-options)**: These change the behavior of the planning
|
|
command itself, rather than customizing the content of the generated plan.
|
|
|
|
## Planning Modes
|
|
|
|
The section above described Terraform's default planning behavior, which is
|
|
intended for changing the remote system to match with changes you've made to
|
|
your configuration.
|
|
|
|
Terraform has two alternative planning modes, each of which creates a plan with
|
|
a different intended outcome:
|
|
|
|
* **Destroy mode:** creates a plan whose goal is to destroy all remote objects
|
|
that currently exist, leaving an empty Terraform state. This can be useful
|
|
for situations like transient development environments, where the managed
|
|
objects cease to be useful once the development task is complete.
|
|
|
|
Activate destroy mode using the `-destroy` command line option.
|
|
|
|
* **Refresh-only mode:** creates a plan whose goal is only to update the
|
|
Terraform state and any root module output values to match changes made to
|
|
remote objects outside of Terraform. This can be useful if you've
|
|
intentionally changed one or more remote objects outside of the usual
|
|
workflow (e.g. while responding to an incident) and you now need to reconcile
|
|
Terraform's records with those changes.
|
|
|
|
Activate refresh-only mode using the `-refresh-only` command line option.
|
|
|
|
In situations where we need to discuss the default planning mode that Terraform
|
|
uses when none of the alternative modes are selected, we refer to it as
|
|
"Normal mode". Because these alternative modes are for specialized situations
|
|
only, some other Terraform documentation only discusses the normal planning
|
|
mode.
|
|
|
|
The planning modes are all mutually-exclusive, so activating any non-default
|
|
planning mode disables the "normal" planning mode, and you can't use more than
|
|
one alternative mode at the same time.
|
|
|
|
-> **Note:** In Terraform v0.15 and earlier, the `-destroy` option is
|
|
supported only by the `terraform plan` command, and not by the
|
|
`terraform apply` command. To create and apply a plan in destroy mode in
|
|
earlier versions you must run [`terraform destroy`](/cli/commands/destroy).
|
|
|
|
-> **Note:** The `-refresh-only` option is available only in Terraform v0.15.4
|
|
and later.
|
|
|
|
> **Hands-on:** Try the [Use Refresh-Only Mode to Sync Terraform State](https://learn.hashicorp.com/tutorials/terraform/refresh) tutorial on HashiCorp Learn.
|
|
|
|
## Planning Options
|
|
|
|
In addition to the planning _modes_ described above, there are also several
|
|
additional options that can modify details of the behavior of the planning
|
|
step.
|
|
|
|
When you use `terraform apply` without passing it a saved plan file, it
|
|
incorporates the `terraform plan` command functionality and so the planning
|
|
options in this section, along with the planning mode selection options in
|
|
the previous section, are also available with the same meanings on
|
|
`terraform apply`.
|
|
|
|
* `-refresh=false` - Disables the default behavior of synchronizing the
|
|
Terraform state with remote objects before checking for configuration changes.
|
|
|
|
This option can potentially make the planning operation faster by reducing
|
|
the number of remote API requests, but it comes at the expense of having
|
|
Terraform not take into account any changes that might've happened outside
|
|
of Terraform, and thus the resulting plan may not be complete or correct.
|
|
|
|
This option is not available in the "refresh only" planning mode, because
|
|
it would effectively disable the entirety of the planning operation in that
|
|
case.
|
|
|
|
* `-replace=ADDRESS` - Instructs Terraform to plan to replace the single
|
|
resource instance with the given address. If the given instance would
|
|
normally have caused only an "update" action, or no action at all, then
|
|
Terraform will choose a "replace" action instead.
|
|
|
|
You can use this option if you have learned that a particular remote object
|
|
has become degraded in some way. If you are using immutable infrastructure
|
|
patterns then you may wish to respond to that by replacing the
|
|
malfunctioning object with a new object that has the same configuration.
|
|
|
|
This option is allowed only in the normal planning mode, so this option
|
|
is incompatible with the `-destroy` option.
|
|
|
|
The `-replace=...` option is available only from Terraform v0.15.2 onwards.
|
|
For earlier versions, you can achieve a similar effect (with some caveats)
|
|
using [`terraform taint`](/cli/commands/taint).
|
|
|
|
* `-target=ADDRESS` - Instructs Terraform to focus its planning efforts only
|
|
on resource instances which match the given address and on any objects that
|
|
those instances depend on.
|
|
|
|
This command is for exceptional use only. See
|
|
[Resource Targeting](#resource-targeting)
|
|
below for more information.
|
|
|
|
* `-var 'NAME=VALUE'` - Sets a value for a single
|
|
[input variable](/language/values/variables) declared in the
|
|
root module of the configuration. Use this option multiple times to set
|
|
more than one variable. For more information see
|
|
[Input Variables on the Command Line](#input-variables-on-the-command-line),
|
|
below.
|
|
|
|
* `-var-file=FILENAME` - Sets values for potentially many
|
|
[input variables](/language/values/variables) declared in the
|
|
root module of the configuration, using definitions from a
|
|
["tfvars" file](/language/values/variables#variable-definitions-tfvars-files).
|
|
Use this option multiple times to include values from more than one file.
|
|
|
|
There are several other ways to set values for input variables in the root
|
|
module, aside from the `-var` and `-var-file` options. For more information,
|
|
see
|
|
[Assigning Values to Root Module Variables](/language/values/variables#assigning-values-to-root-module-variables).
|
|
|
|
### Input Variables on the Command Line
|
|
|
|
You can use the `-var` command line option to specify values for
|
|
[input variables](/language/values/variables) declared in your
|
|
root module.
|
|
|
|
However, to do so will require writing a command line that is parsable both
|
|
by your chosen command line shell _and_ Terraform, which can be complicated
|
|
for expressions involving lots of quotes and escape sequences. In most cases
|
|
we recommend using the `-var-file` option instead, and write your actual values
|
|
in a separate file so that Terraform can parse them directly, rather than
|
|
interpreting the result of your shell's parsing.
|
|
|
|
To use `-var` on a Unix-style shell on a system like Linux or macOS we
|
|
recommend writing the option argument in single quotes `'` to ensure the
|
|
shell will interpret the value literally:
|
|
|
|
```
|
|
terraform plan -var 'name=value'
|
|
```
|
|
|
|
If your intended value also includes a single quote then you'll still need to
|
|
escape that for correct interpretation by your shell, which also requires
|
|
temporarily ending the quoted sequence so that the backslash escape character
|
|
will be significant:
|
|
|
|
```
|
|
terraform plan -var 'name=va'\''lue'
|
|
```
|
|
|
|
When using Terraform on Windows, we recommend using the Windows Command Prompt
|
|
(`cmd.exe`). When you pass a variable value to Terraform from the Windows
|
|
Command Prompt, use double quotes `"` around the argument:
|
|
|
|
```
|
|
terraform plan -var "name=value"
|
|
```
|
|
|
|
If your intended value includes literal double quotes then you'll need to
|
|
escape those with a backslash:
|
|
|
|
```
|
|
terraform plan -var "name=va\"lue"
|
|
```
|
|
|
|
PowerShell on Windows cannot correctly pass literal quotes to external programs,
|
|
so we do not recommend using Terraform with PowerShell when you are on Windows.
|
|
Use Windows Command Prompt instead.
|
|
|
|
The appropriate syntax for writing the variable value is different depending
|
|
on the variable's [type constraint](/language/expressions/type-constraints).
|
|
The primitive types `string`, `number`, and `bool` all expect a direct string
|
|
value with no special punctuation except that required by your shell, as
|
|
shown in the above examples. For all other type constraints, including list,
|
|
map, and set types and the special `any` keyword, you must write a valid
|
|
Terraform language expression representing the value, and write any necessary
|
|
quoting or escape characters to ensure it will pass through your shell
|
|
literally to Terraform. For example, for a `list(string)` type constraint:
|
|
|
|
```
|
|
# Unix-style shell
|
|
terraform plan -var 'name=["a", "b", "c"]'
|
|
|
|
# Windows Command Prompt (do not use PowerShell on Windows)
|
|
terraform plan -var "name=[\"a\", \"b\", \"c\"]"
|
|
```
|
|
|
|
Similar constraints apply when setting input variables using environment
|
|
variables. For more information on the various methods for setting root module
|
|
input variables, see
|
|
[Assigning Values to Root Module Variables](/language/values/variables#assigning-values-to-root-module-variables).
|
|
|
|
### Resource Targeting
|
|
|
|
> **Hands-on:** Try the [Target resources](https://learn.hashicorp.com/tutorials/terraform/resource-targeting?in=terraform/state&utm_source=WEBSITE&utm_medium=WEB_IO&utm_offer=ARTICLE_PAGE&utm_content=DOCS) tutorial on HashiCorp Learn.
|
|
|
|
You can use the `-target` option to focus Terraform's attention on only a
|
|
subset of resources.
|
|
You can use [resource address syntax](/cli/state/resource-addressing)
|
|
to specify the constraint. Terraform interprets the resource address as follows:
|
|
|
|
* If the given address identifies one specific resource instance, Terraform
|
|
will select that instance alone. For resources with either `count` or
|
|
`for_each` set, a resource instance address must include the instance index
|
|
part, like `aws_instance.example[0]`.
|
|
|
|
* If the given address identifies a resource as a whole, Terraform will select
|
|
all of the instances of that resource. For resources with either `count`
|
|
or `for_each` set, this means selecting _all_ instance indexes currently
|
|
associated with that resource. For single-instance resources (without
|
|
either `count` or `for_each`), the resource address and the resource instance
|
|
address are identical, so this possibility does not apply.
|
|
|
|
* If the given address identifies an entire module instance, Terraform will
|
|
select all instances of all resources that belong to that module instance
|
|
and all of its child module instances.
|
|
|
|
Once Terraform has selected one or more resource instances that you've directly
|
|
targeted, it will also then extend the selection to include all other objects
|
|
that those selections depend on either directly or indirectly.
|
|
|
|
This targeting capability is provided for exceptional circumstances, such
|
|
as recovering from mistakes or working around Terraform limitations. It
|
|
is _not recommended_ to use `-target` for routine operations, since this can
|
|
lead to undetected configuration drift and confusion about how the true state
|
|
of resources relates to configuration.
|
|
|
|
Instead of using `-target` as a means to operate on isolated portions of very
|
|
large configurations, prefer instead to break large configurations into
|
|
several smaller configurations that can each be independently applied.
|
|
[Data sources](/language/data-sources) can be used to access
|
|
information about resources created in other configurations, allowing
|
|
a complex system architecture to be broken down into more manageable parts
|
|
that can be updated independently.
|
|
|
|
## Other Options
|
|
|
|
The `terraform plan` command also has some other options that are related to
|
|
the input and output of the planning command, rather than customizing what
|
|
sort of plan Terraform will create. These commands are not necessarily also
|
|
available on `terraform apply`, unless otherwise stated in the documentation
|
|
for that command.
|
|
|
|
The available options are:
|
|
|
|
* `-compact-warnings` - Shows any warning messages in a compact form which
|
|
includes only the summary messages, unless the warnings are accompanied by
|
|
at least one error and thus the warning text might be useful context for
|
|
the errors.
|
|
|
|
* `-detailed-exitcode` - Returns a detailed exit code when the command exits.
|
|
When provided, this argument changes the exit codes and their meanings to
|
|
provide more granular information about what the resulting plan contains:
|
|
* 0 = Succeeded with empty diff (no changes)
|
|
* 1 = Error
|
|
* 2 = Succeeded with non-empty diff (changes present)
|
|
|
|
* `-input=false` - Disables Terraform's default behavior of prompting for
|
|
input for root module input variables that have not otherwise been assigned
|
|
a value. This option is particularly useful when running Terraform in
|
|
non-interactive automation systems.
|
|
|
|
* `-json` - Enables the [machine readable JSON UI][machine-readable-ui] output.
|
|
This implies `-input=false`, so the configuration must have no unassigned
|
|
variable values to continue.
|
|
|
|
[machine-readable-ui]: /internals/machine-readable-ui
|
|
|
|
* `-lock=false` - Don't hold a state lock during the operation. This is
|
|
dangerous if others might concurrently run commands against the same
|
|
workspace.
|
|
|
|
* `-lock-timeout=DURATION` - Unless locking is disabled with `-lock=false`,
|
|
instructs Terraform to retry acquiring a lock for a period of time before
|
|
returning an error. The duration syntax is a number followed by a time
|
|
unit letter, such as "3s" for three seconds.
|
|
|
|
* `-no-color` - Disables terminal formatting sequences in the output. Use this
|
|
if you are running Terraform in a context where its output will be
|
|
rendered by a system that cannot interpret terminal formatting.
|
|
|
|
* `-out=FILENAME` - Writes the generated plan to the given filename in an
|
|
opaque file format that you can later pass to `terraform apply` to execute
|
|
the planned changes, and to some other Terraform commands that can work with
|
|
saved plan files.
|
|
|
|
Terraform will allow any filename for the plan file, but a typical
|
|
convention is to name it `tfplan`. **Do not** name the file with a suffix
|
|
that Terraform recognizes as another file format; if you use a `.tf` suffix
|
|
then Terraform will try to interpret the file as a configuration source
|
|
file, which will then cause syntax errors for subsequent commands.
|
|
|
|
The generated file is not in any standard format intended for consumption
|
|
by other software, but the file _does_ contain your full configuration,
|
|
all of the values associated with planned changes, and all of the plan
|
|
options including the input variables. If your plan includes any sort of
|
|
sensitive data, even if obscured in Terraform's terminal output, it will
|
|
be saved in cleartext in the plan file. You should therefore treat any
|
|
saved plan files as potentially-sensitive artifacts.
|
|
|
|
* `-parallelism=n` - Limit the number of concurrent operations as Terraform
|
|
[walks the graph](/internals/graph#walking-the-graph). Defaults
|
|
to 10.
|
|
|
|
For configurations using
|
|
[the `local` backend](/language/settings/backends/local) only,
|
|
`terraform plan` accepts the legacy command line option
|
|
[`-state`](/language/settings/backends/local#command-line-arguments).
|
|
|
|
### Passing a Different Configuration Directory
|
|
|
|
Terraform v0.13 and earlier accepted an additional positional argument giving
|
|
a directory path, in which case Terraform would use that directory as the root
|
|
module instead of the current working directory.
|
|
|
|
That usage was deprecated in Terraform v0.14 and removed in Terraform v0.15.
|
|
If your workflow relies on overriding the root module directory, use
|
|
[the `-chdir` global option](/cli/commands/#switching-working-directory-with-chdir)
|
|
instead, which works across all commands and makes Terraform consistently look
|
|
in the given directory for all files it would normally read or write in the
|
|
current working directory.
|
|
|
|
If your previous use of this legacy pattern was also relying on Terraform
|
|
writing the `.terraform` subdirectory into the current working directory even
|
|
though the root module directory was overridden, use
|
|
[the `TF_DATA_DIR` environment variable](/cli/config/environment-variables#tf_data_dir)
|
|
to direct Terraform to write the `.terraform` directory to a location other
|
|
than the current working directory.
|