Using ramdisk as LXD storage for the runners

[yhaliaw]

No description provided.

[github-actions]

Test coverage for aac67ac

Name                                    Stmts   Miss Branch BrPart  Cover   Missing
-----------------------------------------------------------------------------------
src/charm.py                              327     66     74     17    78%   163->170, 171->exit, 254-259, 268, 277-287, 303-305, 313-316, 322, 333, 344->361, 349-354, 371-372, 376-377, 382-385, 398-399, 401-402, 436-444, 455-456, 474-476, 479->exit, 483-485, 508-513, 523-524, 526-527, 529-530, 629-630, 640
src/errors.py                              22      0      0      0   100%
src/event_timer.py                         42      8      4      0    74%   96-99, 119-122
src/github_type.py                         36      0      0      0   100%
src/lxd_type.py                            41      0      2      0   100%
src/repo_policy_compliance_service.py       5      5      0      0     0%   4-14
src/runner.py                             212     24     52     16    85%   164-171, 177-183, 243, 261, 298-300, 307, 321, 331, 350, 384-389, 399, 483, 516, 542, 547-559, 573, 591
src/runner_manager.py                     196     20     80      8    88%   205-206, 220-226, 230-232, 242-243, 296, 321-325, 344, 362, 478, 498
src/runner_type.py                         47      0     10      0   100%
src/utilities.py                           55      2     12      4    91%   74->76, 78->84, 89-91
-----------------------------------------------------------------------------------
TOTAL                                     983    125    234     45    85%

Static code analysis report

Run started:2023-06-20 11:00:06.434016

Test results:
  No issues identified.

Code scanned:
  Total lines of code: 2211
  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):

[yhaliaw]

From manual testing, it seems the memory that is used by the LXD storage is not getting free.

I was able to cause the juju machine to OOM. The LXD was crashing at that point.
Using lxc storage volume list reveal the LXD volumes created are getting delete, but the memory used by the ramdisk is not getting freed.
Attempting another method for now.