Terraform Error: Value for undeclared variable - A Variable Named Was Assigned on the Command Line (Terraform 1.17 Fix)

Fri, 16 Apr 2021 00:00:00 +0000

TL;DR

The error means one thing: you passed -var="name=value" and the root module has no variable "name" {} block. Terraform 1.17.1 prints Error: Value for undeclared variable and exits with code 1 before it plans anything.
The fix is one of two lines: add the variable block to a .tf file in the directory you run Terraform from, or correct the spelling of the name you pass. Names are case sensitive: Env and env are different variables.
The same mistake is only a warning in a .tfvars file (plan continues, exit code 0), and it is ignored silently when it comes from a TF_VAR_ environment variable. A wrong argument inside a module block is a third, different error: Unsupported argument.
Not your exact case? If your error says No value for required variable instead, the variable is declared but empty; read Terraform variables and tfvars files. For the full list of variable types, read Terraform input variables.

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