Terraform Vault Provider Namespace is not working as a Provider Alias

Introduction

When configuring the Terraform Vault provider, you can use provider aliases to interact with multiple Vault namespaces within the same configuration. However, you may encounter an error if the alias name contains special characters.

Problem

When you define an aliased Vault provider where the alias argument contains a forward slash (/) to match the namespace path, Terraform returns an error.

provider "vault" {
  alias     = "admin/dev"
  namespace = "admin/dev"
}

This configuration produces the following error message.

│ Error: error reading from Vault: Error making API request.
│
│ Namespace: admin/│ URL: GET https://x.x.x.x
│ Code: 400. Errors:
│
│ * "/" is not allowed in namespace names

Cause

The alias argument in a Terraform provider block has naming constraints and does not permit certain special characters, including the forward slash (/). While the namespace argument can contain a forward slash to represent a path, the alias argument cannot.

Solutions

Solution 1: Replace Special Characters in the Alias

To resolve this issue, replace the forward slash (/) in the alias argument with a character that is valid for provider aliases, such as a hyphen (-). The namespace argument should remain unchanged.

provider "vault" {
  alias     = "admin-dev"
  namespace = "admin/dev"
}

This revised configuration allows Terraform to correctly parse the provider alias while still targeting the desired Vault namespace.

Additional Information

For more details on configuring provider aliases, refer to the official Vault Provider Aliases documentation.