Bootstrap & join with a fixed containerd-base-dir

[addyess]

Applicable spec: #238

Overview

Bootstraps, and joins nodes using the charm specified containerd base path

Rationale

The snap config now allows the charm to specify a containerd-base-dir, Lets use that to make sure it doesn't move again.

Library Changes

Updated the k8s library to accommodate new API config

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 7d86134

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     286     29    90%
src/charm.py                              501    260    48%
src/cloud_integration.py                   80      3    96%
src/config/extra_args.py                   31      2    94%
src/containerd.py                         140     22    84%
src/cos_integration.py                     33     12    64%
src/events/update_status.py                68     24    65%
src/inspector.py                           41      4    90%
src/kube_control.py                        43     32    26%
src/literals.py                            25      0   100%
src/protocols.py                           28      5    82%
src/reschedule.py                          77      4    95%
src/snap.py                               193     29    85%
src/token_distributor.py                  181    109    40%
src/upgrade.py                            108     48    56%
-----------------------------------------------------------
TOTAL                                    1835    583    68%
coverage-report: OK (1.22=setup[1.00]+cmd[0.21] seconds)
congratulations :) (1.26 seconds)

Static code analysis report

Run started:2025-01-09 22:20:54.508680

Test results:
  No issues identified.

Code scanned:
  Total lines of code: 3910
  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]

LGTM, thanks for adding the config.
It would be nice to have tests on setting the bootstrap & join config?

[addyess]

@louiseschmidtgen i was counting on the integration tests that normally run

• they bootstrap one node
• another node will join as a control plane
• another node will join as a worker

I've produced a card for future tests to exercise the custom-registry feature for the next pulse.