inital pass at adding terraform for the k8s charms

[asbalderson]

Applicable spec: https://docs.google.com/document/d/1EG71A2pJ244PQRaGVzGj7Mx2B_bzE4U_OSqx4eeVI1E/edit?tab=t.0

Overview

Adds basic terraform modules for the k8s charms

Rationale

Enable deploying canonical k8s with terraform

Juju Events Changes

N/A

Module Changes

N/A

Library Changes

N/A

Checklist

• The charm style guide was applied
• The contributing guide was applied
• The changes are compliant with ISD054 - Managing Charm Complexity
• The documentation is generated using src-docs
• The documentation for charmhub is updated
• The PR is tagged with appropriate label (urgent, trivial, complex)

[github-actions]

Test coverage for 2a1d220

coverage-report: install_deps /home/runner/work/k8s-operator/k8s-operator/charms/worker/k8s> python -I -m pip install 'coverage[toml]'
coverage-report: commands[0] /home/runner/work/k8s-operator/k8s-operator/charms/worker/k8s> coverage report
Name                                    Stmts   Miss  Cover
-----------------------------------------------------------
lib/charms/k8s/v0/k8sd_api_manager.py     278     29    90%
src/charm.py                              473    233    51%
src/cloud_integration.py                   80      3    96%
src/config/extra_args.py                   27      1    96%
src/containerd.py                         140     16    89%
src/cos_integration.py                     33     12    64%
src/events/update_status.py                48     10    79%
src/inspector.py                           40      4    90%
src/kube_control.py                        39     31    21%
src/literals.py                             1      0   100%
src/protocols.py                           16      3    81%
src/reschedule.py                          77      4    95%
src/snap.py                               165     10    94%
src/token_distributor.py                  181    109    40%
src/upgrade.py                             31      1    97%
-----------------------------------------------------------
TOTAL                                    1629    466    71%
coverage-report: OK (1.23=setup[1.02]+cmd[0.20] seconds)
congratulations :) (1.28 seconds)

Static code analysis report

Run started:2024-12-02 21:08:59.067008

Test results:
  No issues identified.

Code scanned:
  Total lines of code: 3534
  Total lines skipped (#nosec): 3
  Total potential issues skipped due to specifically being disabled (e.g., #nosec BXXX): 0

Run metrics:
  Total issues (by severity):
  	Undefined: 0
  	Low: 0
  	Medium: 0
  	High: 0
  Total issues (by confidence):
  	Undefined: 0
  	Low: 0
  	Medium: 0
  	High: 0
Files skipped (0):

[louiseschmidtgen]

Did a first pass on the templates, thank you so much for your work! I believe these should find a separate repo to live in.

[louiseschmidtgen]

Does this tf deploy work for strict as well?

[louiseschmidtgen]

Suggested change

	Define a `data` source and pass to the `model_name` input a reference to the `data.juju_model` resource's name. This will enable Terraform to look for a `juju_model` resource with a name attribute equal to the one provided, and apply only if this is present. Otherwise, it will fail before applying anything.
	Define a `data` source and pass a reference to the `model_name` input to the `data.juju_model` resource's name. Terraform will look for a `juju_model` resource with a matching model name and only apply resources if the names match.

[louiseschmidtgen]

Suggested change

	variable "series" {
	description = "Ubuntu series to deploy the charm onto"
	type = string
	default = "24.04"
	validation {
	condition = contains(["20.04", "22.04", "24.04"], var.series)
	error_message = "Series must be one of 20.04, 22.04, 24.04"
	}
	}
	variable "base" {
	description = "Ubuntu series to deploy the charm onto"
	type = string
	default = "ubuntu@24.04"
	validation {
	condition = contains(["ubuntu@20.04", "ubuntu@22.04", "ubuntu@24.04"], var.base)
	error_message = "Series must be one of ubuntu@20.04, ubuntu@22.04, ubuntu@24.04"
	}
	}

Let's use base here since series attribute will be removed in the next major version of the provider.