Import Usage
Use the opentf import
command to import existing infrastructure to OpenTF state.
The opentf import
command can only import one resource at a time. It cannot simultaneously import an entire collection of resources, like an AWS VPC.
~> Warning: OpenTF expects that each remote object it is managing will be bound to only one resource address, which is normally guaranteed by OpenTF itself having created all objects. If you import existing objects into OpenTF, be careful to import each remote object to only one OpenTF resource address. If you import the same object multiple times, OpenTF may exhibit unwanted behavior. For more information on this assumption, see the State section.
To import a resource, first write a resource block for it in your configuration, establishing the name by which it will be known to OpenTF:
resource "aws_instance" "example" {
# ...instance configuration...
}
The name "example" here is local to the module where it is declared and is chosen by the configuration author. This is distinct from any ID issued by the remote system, which may change over time while the resource name remains constant.
If desired, you can leave the body of the resource block blank for now and return to fill it in once the instance is imported.
Now opentf import
can be run to attach an existing instance to this
resource configuration:
$ opentf import aws_instance.example i-abcd1234
This command locates the AWS EC2 instance with ID i-abcd1234
. Then it attaches
the existing settings of the instance, as described by the EC2 API, to the
name aws_instance.example
of a module. In this example the module path
implies that the root module is used. Finally, the mapping is saved in the
OpenTF state.
It is also possible to import to resources in child modules, using their paths,
and to single instances of a resource with count
or for_each
set. See
Resource Addressing for more
details on how to specify a target resource.
The syntax of the given ID is dependent on the resource type being imported. For example, AWS instances use an opaque ID issued by the EC2 API, but AWS Route53 Zones use the domain name itself. Consult the documentation for each importable resource for details on what form of ID is required.
As a result of the above command, the resource is recorded in the state file.
You can now run opentf plan
to see how the configuration compares to
the imported resource, and make any adjustments to the configuration to
align with the current (or desired) state of the imported object.
Complex Imports
The above import is considered a "simple import": one resource is imported
into the state file. An import may also result in a "complex import" where
multiple resources are imported. For example, an AWS network ACL imports
an aws_network_acl
but also one aws_network_acl_rule
for each rule.
In this scenario, the secondary resources will not already exist in
configuration, so it is necessary to consult the import output and create
a resource
block in configuration for each secondary resource. If this is
not done, OpenTF will plan to destroy the imported objects on the next run.
If you want to rename or otherwise move the imported resources, the state management commands can be used.