Resolving Conflicts in Atlas Remote State

Resolving state conflicts can be time consuming and error prone, so it's important to approach it carefully.

There are several tools provided by Atlas to help resolve conflicts and fix remote state issues. First, you can navigate between state versions in the changes view of your environment (after toggling on the remote state checkbox) and view plain-text differences between versions.

This allows you to pinpoint where things may have gone wrong and make a educated decision about resolving the conflict.

Rolling Back to a Specific State Version

The rollback feature allows you to choose a new version to set as the "Head" version of the state. Rolling back to a version means it will then return that state upon request from a client. It will not increment the serial in the state, but perform a hard rollback to the exact version of the state provided.

This allows you to reset the state to an older version, essentially forgetting changes made in versions after that point.

To roll back to a specific version, navigate to it in the changes view and use the rollback link. You'll need to confirm the version number to perform the operation.

Using Terraform Locally

Another way to resolve conflicts in Atlas remote state is to merge and conflicted copies locally by inspecting the raw state available in the path .terraform/terraform.tfstate.

When making state changes, it's important to make backup copies in order to avoid losing any data.

Atlas will reject any state that is pushed with a serial that is lower than the known serial when the MD5 of the state does not match.

The serial is embedded in the state file:

{
  "version": 1,
  "serial": 555,
  "remote": {
    "type": "atlas",
    "config": {
      "name": "acmeinc/production"
    }
  },
  ...
}

Once a conflict has been resolved locally by editing the state file, the serial can be incremented past the current version in Atlas and pushed:

terraform remote push

This will upload the manually resolved state and set it as the head version in Atlas.