fix(mariadb): add bounded Galera ordered shutdown

[weicao]

Summary

• keep Galera podManagementPolicy: Parallel and replace the inline preStop block with /scripts/galera-prestop.sh
• add bounded shutdown ordering: lower ordinals wait for higher ordinals to stop, log degraded ordering on timeout, then still cleanly shut down locally
• run local Galera shutdown cleanup as wsrep_desync=ON, wsrep_on=OFF, then mysqladmin shutdown
• bump the MariaDB chart to 1.2.0-alpha.27 and add focused ShellSpec coverage

This supersedes PR #3105 as the selected route. PR #3105 remains useful only as the OrderedReady trade-off evidence and should not be merged.

Validation

• bash -n addons/mariadb/scripts/galera-prestop.sh addons/mariadb/scripts/galera-start.sh
• shellspec --load-path ./shellspec --shell bash addons/mariadb/scripts-ut-spec/galera_start_spec.sh addons/mariadb/scripts-ut-spec/galera_prestop_spec.sh addons/mariadb/scripts-ut-spec/galera_parallel_shutdown_template_spec.sh
  • 21 examples, 0 failures
• helm dependency build addons/mariadb
• helm template mariadb addons/mariadb >/tmp/mariadb-galera-render.yaml plus render grep confirmed:
  • mariadb-galera-1.2.0-alpha.27
  • podManagementPolicy: Parallel
  • mounted galera-prestop.sh
  • preStop calls /scripts/galera-prestop.sh

Full MariaDB ShellSpec was also run:

• shellspec --load-path ./shellspec --shell bash addons/mariadb/scripts-ut-spec
  • 672 examples, 7 failures, 9 pendings
  • the 7 failures are all in replication_merged_replication_mode_env_wire_spec.sh, unrelated to the Galera files changed here

Runtime validation needed

Before marking ready, run IDC validation for:

• fresh 3-node Galera create under Parallel
• normal Stop/Start with grastate.dat proof and auto-recovery
• high-ordinal safe_to_bootstrap=1 full force-delete recovery
• abnormal/slow pod-1 shutdown timeout: bounded wait, degraded log, no indefinite block, no false success
• T9/T10/T11/T12 no-regression scope

[codecov-commenter]

Codecov Report

❌ Patch coverage is 0% with 89 lines in your changes missing coverage. Please review.
✅ Project coverage is 0.00%. Comparing base (2e74b1d) to head (80cf583).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
...ons/mariadb/scripts-ut-spec/galera_prestop_spec.sh	0.00%	55 Missing ⚠️
...-ut-spec/galera_parallel_shutdown_template_spec.sh	0.00%	24 Missing ⚠️
...adb/scripts-ut-spec/replication_switchover_spec.sh	0.00%	8 Missing ⚠️
...ripts-ut-spec/replication_user_convergence_spec.sh	0.00%	2 Missing ⚠️

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #3108   +/-   ##
=====================================
  Coverage   0.00%   0.00%           
=====================================
  Files        144     146    +2     
  Lines      23013   23092   +79     
=====================================
- Misses     23013   23092   +79     

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.