[YUNIKORN-2107] Allow preemption to be disabled globally

[craigcondit]

What is this PR for?

Added configuration service.disablePreemption which can be used to disable the preemption subsystem entirely when set to true.

What type of PR is it?

• - Bug Fix
• - Improvement
• - Feature
• - Documentation
• - Hot Fix
• - Refactoring

Todos

• - Task

What is the Jira issue?

https://issues.apache.org/jira/browse/YUNIKORN-2107

How should this be tested?

Added unit tests.

Screenshots (if appropriate)

Questions:

• - The licenses files need update.
• - There is breaking changes for older versions.
• - It needs documentation.

[wilfred-s]

Why not use the existing parameter in the partition config for this? (See jira for details also)

[codecov]

Codecov Report

Merging #690 (0642f8a) into master (47ca6fe) will increase coverage by 0.05%.
Report is 6 commits behind head on master.
The diff coverage is 80.00%.

@@            Coverage Diff             @@
##           master     #690      +/-   ##
==========================================
+ Coverage   77.57%   77.63%   +0.05%     
==========================================
  Files          80       80              
  Lines       13133    13271     +138     
==========================================
+ Hits        10188    10303     +115     
- Misses       2619     2648      +29     
+ Partials      326      320       -6     

Files	Coverage Δ
pkg/common/configs/config.go	100.00% <ø> (ø)
pkg/scheduler/objects/application.go	68.29% <100.00%> (ø)
pkg/scheduler/partition.go	78.58% <100.00%> (+0.16%)	⬆️
pkg/scheduler/objects/queue.go	77.66% <0.00%> (ø)

... and 9 files with indirect coverage changes

📣 Codecov offers a browser extension for seamless coverage viewing on GitHub. Try it in Chrome or Firefox today!

[craigcondit]

Why not use the existing parameter in the partition config for this? (See jira for details also)

Because then we end up with opt-in preemption rather than opt out as there's no distinction in the existing configuration between Enabled: false and not specified. That's backwards-incompatible.

Managed to get this working by changing the type of the Enabled field in the config to *bool, so we can detect unset values and default to true.

[pbacsko]

+1