Ephemeral resources

:::info Ephemeral resources can be used only with OpenTofu from v1.11 onwards. :::

The ephemeral block defines a temporary value that OpenTofu will not store in state or plan. This block works only with providers that already offer such capability and is not meant to be used as a drop-in replacement for other blocks (data or resource). To understand if providers offer such capability, the provider documentation or schema should be consulted.

Lifecycle

The lifecycle of an ephemeral resource is different than the lifecycle of other resource types. When OpenTofu encounters such a block, it will execute the following sequence:

• Validate the configuration using the specified provider.
• Open the ephemeral resource to retrieve the value from the provider.
• Close the ephemeral resource when it is no longer needed in the execution of the current phase

Any attribute of the response returned by opening the ephemeral resource, is marked as ephemeral and can only be used in specific contexts:

• Ephemeral Resources
• Ephemeral Variables
• Ephemeral Outputs
• Locals
• Providers
• Provisioners
• Resource connection blocks
• Resource write-only attributes

Any usage of an ephemeral value in contexts where is not allowed will generate an error.

Configuration structure

Besides the attributes in the schema of an ephemeral resource, the block supports also the following meta-arguments:

• depends_on
• count
• for_each
• provider
• lifecycle

Lifecycle Customizations

A lifecycle block inside an ephemeral block allows some customization of OpenTofu's behavior relating to instances of a resource at different phases of its lifecycle.

ephemeral "example" "example" {
  # ...normal resource arguments...

  lifecycle {
    # ...lifecycle arguments...
  }
}

The following arguments and nested block types are supported in the lifecycle block for an ephemeral resource:

• enabled (bool) - Controls whether the ephemeral resource will be used by OpenTofu. When set to false, the resource is excluded from the configuration as if it didn't exist. When set to true (the default), the resource operates normally.

  For ephemeral resources in particular, you can use the boolean terraform.applying value with enabled to specify that a particular ephemeral resource should be active only during the apply phase, which can be useful for values used only by managed resource provisioners because provisioners are active only during the apply phase.

  For more information, refer to the enabled meta-argument.

• precondition and postcondition blocks, as described in Custom Conditions.

Deferred opening

By design, the ephemeral resources cannot be opened if the configuration is not fully known. When that happens during planning, the ephemeral resource will be postponed (deferred) for the apply phase. On the apply phase, based on the dependency graph, the ephemeral resource will be opened only after all of its dependencies will be satisfied.

Example

For an in-depth example on how to use ephemeral resources, please refer to this example.