Force re-creation of resources (taint)

During planning, by default Terraform retrieves the latest state of each existing object and compares it with the current configuration, planning actions only against objects whose current state does not match the configuration.

However, in some cases a remote object may become damaged or degraded in a way that Terraform cannot automatically detect. For example, if software running inside a virtual machine crashes but the virtual machine itself is still running then Terraform will typically have no way to detect and respond to the problem, because Terraform only directly manages the machine as a whole.

If you know that an object is damaged, or if you want to force Terraform to replace it for any other reason, you can override Terraform's default behavior using the -replace=... planning option when you run either terraform plan or terraform apply:

$ terraform apply -replace="aws_instance.example"
# ...

  # aws_instance.example will be replaced, as requested
-/+ resource "aws_instance" "example" {
      # ...
    }

The "tainted" status

Sometimes Terraform is able to infer automatically that an object is in an incomplete or degraded state. For example, if creation of a complex object fails in such a way that parts of it already exist in the remote system, or if object creation succeeded but a provisioner step subsequently failed, Terraform must remember that the object exists but may not be fully-functional.

Terraform represents this situation by marking an object in the state as "tainted". When an object is marked with this status, the next plan will force replacing that object in a similar way to if you had specified that object's address using -replace=... as described above.

  # aws_instance.example is tainted, so must be replaced
-/+ resource "aws_instance" "example" {
      # ...
    }

If Terraform has marked an object as tainted but you consider it to be working correctly and do not want to replace it, you can override Terraform's determination using the terraform untaint command, after which Terraform will consider the object to be ready for use by any downstream resource declarations.

You can also force Terraform to mark a particular object as tainted using the terraform taint command, but that approach is deprecated in favor of the -replace=... option, which avoids the need to create an interim state snapshot with a tainted object.