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State

OpenTF must store state about your managed infrastructure and configuration. This state is used by OpenTF to map real world resources to your configuration, keep track of metadata, and to improve performance for large infrastructures.

This state is stored by default in a local file named "terraform.tfstate", but we recommend storing it in TACOS (TF Automation and Collaboration Software) to version, encrypt, and securely share it with your team.

OpenTF uses state to determine which changes to make to your infrastructure. Prior to any operation, OpenTF does a refresh to update the state with the real infrastructure.

The primary purpose of OpenTF state is to store bindings between objects in a remote system and resource instances declared in your configuration. When OpenTF creates a remote object in response to a change of configuration, it will record the identity of that remote object against a particular resource instance, and then potentially update or delete that object in response to future configuration changes.

For more information on why OpenTF requires state and why OpenTF cannot function without state, please see the page state purpose.

Inspection and Modification​

While the format of the state files are just JSON, direct file editing of the state is discouraged. OpenTF provides the opentf state command to perform basic modifications of the state using the CLI.

The CLI usage and output of the state commands is structured to be friendly for Unix tools such as grep, awk, etc. Additionally, the CLI insulates users from any format changes within the state itself. The OpenTF project will keep the CLI working while the state format underneath it may shift.

OpenTF expects a one-to-one mapping between configured resource instances and remote objects. Normally that is guaranteed by OpenTF being the one to create each object and record its identity in the state, or to destroy an object and then remove the binding for it.

If you add or remove bindings in the state by other means, such as by importing externally-created objects with opentf import, or by asking OpenTF to "forget" an existing object with opentf state rm, you'll then need to ensure for yourself that this one-to-one rule is followed, such as by manually deleting an object that you asked OpenTF to "forget", or by re-importing it to bind it to some other resource instance.

Format​

State snapshots are stored in JSON format and new OpenTF versions are generally backward compatible with state snapshots produced by earlier versions. However, the state format is subject to change in new OpenTF versions, so if you build software that parses or modifies it directly you should expect to perform ongoing maintenance of that software as the state format evolves in new versions.

Alternatively, there are several integration points which produce JSON output that is specifically intended for consumption by external software:

  • The opentf output command has a -json option, for obtaining either the full set of root module output values or a specific named output value from the latest state snapshot.
  • The opentf show command has a -json option for inspecting the latest state snapshot in full, and also for inspecting saved plan files which include a copy of the prior state at the time the plan was made.

A typical way to use these in situations where OpenTF is running in automation is to run them immediately after a successful opentf apply to obtain a representation of the latest state snapshot, and then store that result as an artifact associated with the automated run so that other software can potentially consume it without needing to run OpenTF itself.