Terraform plan -var-file="myvars.vars" does not run
You define variables in variables.tf file. However, you can define inputs to these defined variables in a .tfvars(recommended) or any other files.


  Values for the input variables of a root module can be gathered in variable definition files and passed together using the -var-file=FILE option.
  
  For all files which match terraform.tfvars or *.auto.tfvars present in the current directory, Terraform automatically loads them to populate variables. If the file is located somewhere else, you can pass the path to the file using the -var-file flag. It is recommended to name such files with names ending in .tfvars.
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Make sure you are running terraform plan from the directory where the variable file resides.