Setting an empty value for a Juju model's config key doesn't work

[Gmerold]

Description

Hello Team,

While trying to deploy Canonical K8s on AWS using Terraform following the official How-to I've ran into a problem with setting an empty value for a Juju model's config key. Canonical K8s AWS deployment requires following Juju model settings:

container-networking-method = "local"
fan-config = ""

I've edited the TF module from the guide to include those:

resource "juju_model" "my_model" {
  name = "whatever"
  
  config = {
    container-networking-method = "local"
    fan-config = ""
  }
}

After applying container-networking-method is changed to local, but fan-config remains unchanged.
Handling this two config options might be an edge case which is not properly handed by the provider - before fan-config can be emptied container-networking-method needs to be changed from fan (default value) to something else.

Cheers,
Bart

Urgency

Annoying bug in our test suite

Terraform Juju Provider version

Tested with 0.14.0, 0.15.0 and 0.16.0

Terraform version

v1.10.5

Juju version

3.6.2

Terraform Configuration(s)

Reproduce / Test

Deploy Canonical K8s on AWS using Terraform with https://documentation.ubuntu.com/canonical-kubernetes/latest/charm/howto/install/install-terraform/

Debug/Panic Output

Notes & References

No response

[dparv]

+1

[peppepetra]

This is blocking also deployment of Kubernetes on top of OpenStack

[peppepetra]

I can workaround with

resource "juju_model" "k8s" {
  name       = "k8s"
  credential = var.os_credentials
  cloud {
    name = var.os_cloud
  }

  config = {
    container-networking-method = "local"
    fan-config                  = ""
  }
  provisioner "local-exec" {
    command = "juju model-config fan-config=''"
  }
}