So I wanted to move a database cluster from one Terraform setup to another. I could have used terraform import but this can be a pain.
Instead I used terraform state mv, this post documents some of the pitfalls.
Reading the docs it explains quite simply how to “export” a resource to be imported elsewhere.
terraform state mv -state-out=database.json 'mongodbatlas_cluster.mongodb_cluster' 'mongodbatlas_cluster.mongodb_cluster'
The problem came when using Terraform Cloud, the state file isn’t local at all. This was also a fresh workspace.
First things first, you may need to run the usual terraform init to create that connection to Terraform Cloud
After this we fetch the current (empty) state:
terraform state pull > mystate.json
Run our state mv again to copy the resource into our new state file:
terraform state mv -state=database.json -state-out=mystate.json 'mongodbatlas_cluster.mongodb_cluster' 'mongodbatlas_cluster.mongodb_cluster'
Then we push the state back up to Terraform Cloud:
terraform state push mystate.json
Now, since we had an empty state, perhaps we could have just pushed our database.json straight up, however this method will work for pre-existing workspaces.
If you had your state locally, usually in a terraform.tfstate file in the root directory, things would be a lot more clear.
