Upgrade kernel on charm upgrade

[yhaliaw]

Applicable spec: NA

Overview

Combine the update_dependencies event and the reconcile event.

Update to dependencies and kernel occurs with the reconcile event.

Reboot of the charm is done with juju-reboot command.

Rationale

By combine the update dependencies/kernel with reconcile, the runner spawned should have the latest dependencies and kernel. This should increase the security as the latest version of the dependencies are used.

Juju Events Changes

The update_dependencies custom event is removed.
The reconcile_runners custom event will update the dependencies and kernel as well.

The reconcile_runner_actions will update the dependencies but not the kernel. This is due to juju-reboot is not supported for juju actions:

$ juju help-tool juju-reboot
Usage: juju-reboot [options]

Summary:
Reboot the host machine

Options:
--now  (= false)
    reboot immediately, killing the invoking process

Details:
juju-reboot causes the host machine to reboot, after stopping all containers
	hosted on the machine.

	An invocation without arguments will allow the current hook to complete, and
	will only cause a reboot if the hook completes successfully.

	If the --now flag is passed, the current hook will terminate immediately, and
	be restarted from scratch after reboot. This allows charm authors to write
	hooks that need to reboot more than once in the course of installing software.

	The --now flag cannot terminate a debug-hooks session; hooks using --now should
	be sure to terminate on unexpected errors, so as to guarantee expected behaviour
	in all situations.

	juju-reboot is not supported when running actions.

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)

[yanksyoon]

LGTM, thx!!

[yanksyoon]

LGTM!

[github-actions]

Test coverage for db48389

Name                    Stmts   Miss Branch BrPart  Cover   Missing
-------------------------------------------------------------------
src/charm.py              396     91     93     20    75%   76-78, 104-106, 134-136, 196-204, 216-220, 308-313, 334, 351-357, 366-384, 402-404, 412-415, 422, 425-426, 442, 447-452, 497->500, 513-514, 516-517, 551-558, 582-583, 595-597, 612-613, 638-639, 641-642, 644-645, 712->714, 774-775, 791, 809-811, 815
src/errors.py              23      0      0      0   100%
src/event_timer.py         42      8      4      0    74%   94-97, 117-120
src/firewall.py            43     25     10      0    38%   38-42, 64-67, 75-149
src/github_type.py         36      0      0      0   100%
src/lxd_type.py            37      0      2      0   100%
src/runner.py             259     29     78     22    84%   38->42, 96->98, 192-199, 205-211, 270-275, 280, 300, 349->352, 355-357, 364, 378, 388, 392, 394, 409, 455-460, 470, 559, 594, 620, 625-637, 651, 671
src/runner_manager.py     221     26     88      9    87%   154, 211-213, 226-227, 239-241, 247-252, 256-257, 267-268, 287, 342, 367-371, 390, 408, 551, 571
src/runner_type.py         52      0     12      0   100%
src/utilities.py           68      6     20      8    84%   74->76, 78->84, 89-91, 119, 132, 167, 220
-------------------------------------------------------------------
TOTAL                    1177    185    307     59    82%

Static code analysis report

Run started:2023-09-12 04:21:20.576964

Test results:
  No issues identified.

Code scanned:
  Total lines of code: 2662
  Total lines skipped (#nosec): 0
  Total potential issues skipped due to specifically being disabled (e.g., #nosec BXXX): 9

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):