Terraform auth not working when adding resources - openstack

Question

I wanted to try out terraform on our OpenStack environment. I tried to set it up and it seems to work when only the following is defined:
provider "openstack" {
user_name = "test"
tenant_name = "test"
password = "testpassword"
auth_url = "https://test:5000/v3/"
region = "test"
}
I can run terraform plan without any problem it says:
No changes. Infrastructure is up-to-date.
This means that Terraform did not detect any differences between your
configuration and real physical resources that exist. As a result, no
actions need to be performed.
When i try to add a resource:
resource "openstack_compute_instance_v2" "test" {
name = "test_server"
image_id = "test_id123"
flavor_id = "3"
key_pair = "test"
security_groups = ["default"]
network {
name = "Default Network"
}
}
When i run terraform plan i now get
Error: Error running plan: 1 error(s) occurred:
provider.openstack: Authentication failed

Answer 1

The authentication is working. Something in your provider section is incorrect.
Terraform does not verify the provider information when there is no resource using it.
I validated your findings, and then took it a step farther. I created two providers, one for AWS and one for OpenStack using your example. I then added a resource to create an AWS VPC. My AWS credentials were correct. When I ran terraform plan it returned the action plan for building the VPC. It did not check the fake OpenStack credentials.
One other thing, once there is a resource for a provider it always uses the credentials even if there is nothing to do.
provider "aws" {
access_key = "<redacted>"
secret_key = "<redacted>"
region = "us-east-1"
}
provider "openstack" {
user_name = "test"
tenant_name = "test"
password = "testpassword"
auth_url = "https://test:5000/v3/"
region = "test"
}
/* Create VPC */
resource "aws_vpc" "default" {
cidr_block = "10.200.0.0/16"
enable_dns_support = true
enable_dns_hostnames = true
tags {
Name = "testing"
}
}
Produced the following output verifying the OpenStack provider wasn't checked:
$ terraform plan
Refreshing Terraform state in-memory prior to plan...
The refreshed state will be used to calculate this plan, but will not be
persisted to local or remote state storage.
------------------------------------------------------------------------
An execution plan has been generated and is shown below.
Resource actions are indicated with the following symbols:
+ create
Terraform will perform the following actions:
+ aws_vpc.default
id: <computed>
arn: <computed>
assign_generated_ipv6_cidr_block: "false"
cidr_block: "10.200.0.0/16"
default_network_acl_id: <computed>
default_route_table_id: <computed>
default_security_group_id: <computed>
dhcp_options_id: <computed>
enable_classiclink: <computed>
enable_classiclink_dns_support: <computed>
enable_dns_hostnames: "true"
enable_dns_support: "true"
provider "aws" {
instance_tenancy: "default"
ipv6_association_id: <computed>
ipv6_cidr_block: <computed>
main_route_table_id: <computed>
tags.%: "1"
tags.Name: "testing"
Plan: 1 to add, 0 to change, 0 to destroy.
------------------------------------------------------------------------
Note: You didn't specify an "-out" parameter to save this plan, so Terraform
can't guarantee that exactly these actions will be performed if
"terraform apply" is subsequently run.