Terraform "Unsupported block type" in CI

By Daniel Zoghalchali·Latchkey

A configuration uses a nested block the schema does not recognize. The block name is wrong, or a provider/module upgrade turned that block into an argument (or moved it).

What this error means

validate/plan fails with "Unsupported block type", saying blocks of that type are not expected. It commonly follows a provider upgrade where a nested block was renamed, removed, or converted to an attribute.

terraform output

Error: Unsupported block type

  on main.tf line 10, in resource "aws_instance" "web":
  10:   credit_specification {

Blocks of type "credit_specification" are not expected here.

Common causes

Block renamed, removed, or converted

A newer provider/module version renamed the nested block, removed it, or replaced it with an argument - so the old block is no longer valid.

Wrong block name or placement

A typo in the block name, or nesting a block where the schema expects it elsewhere, triggers "Unsupported block type".

How to fix it

Use the block/argument the schema expects

Check the provider/module docs for the version you run and use the correct nested block or attribute form.

main.tf

# check the docs for your provider version, e.g.
resource "aws_instance" "web" {
  credit_specification {
    cpu_credits = "standard"
  }
}

Reconcile after upgrades

Read the provider/module changelog for changed nested blocks.
Convert removed blocks to their new argument/block form.
Run terraform validate to confirm the structure is accepted.

How to prevent it

Review provider/module upgrade notes for block schema changes.
Pin provider and module versions to keep schemas stable.
Run terraform validate in CI to catch unsupported blocks early.

Frequently asked questions

What causes ""Unsupported block type""?