[Improvement] Add the number of unhealthy nodes in CoordinatorMetrics

[smallzhongfeng]

What changes were proposed in this pull request?

To solve #146

Why are the changes needed?

The number of unhealthy nodes can be viewed on the monitoring.

Does this PR introduce any user-facing change?

No.

How was this patch tested?

No need.

[smallzhongfeng]

cc @jerqi

[codecov-commenter]

Codecov Report

Merging #147 (1ec5d7a) into master (04cbdbb) will increase coverage by 0.05%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##             master     #147      +/-   ##
============================================
+ Coverage     57.20%   57.25%   +0.05%     
- Complexity     1200     1203       +3     
============================================
  Files           150      150              
  Lines          8185     8191       +6     
  Branches        773      774       +1     
============================================
+ Hits           4682     4690       +8     
+ Misses         3257     3256       -1     
+ Partials        246      245       -1     

Impacted Files	Coverage Δ
...apache/uniffle/coordinator/CoordinatorMetrics.java	93.93% <100.00%> (+0.18%)	⬆️
...ache/uniffle/coordinator/SimpleClusterManager.java	89.89% <100.00%> (+1.60%)	⬆️
...e/uniffle/server/storage/SingleStorageManager.java	67.21% <0.00%> (+1.63%)	⬆️

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[jerqi]

Could you add some tests cases in HealthCheckCoordinatorGrpcTest?

[smallzhongfeng]

Could you tell me what needs to be tested. @jerqi Because the current modified method is nodeCheck, I think it is enough not to affect the original test results.WDYT?

[jerqi]

Could you tell me what needs to be tested. @jerqi Because the current modified method is nodeCheck, I think it is enough not to affect the original test results.WDYT?

Just add some extra assertion about like

assertEquals(CoordinatorMetrics.gaugeUnhealthyServerNum.get == 2);

We need test whether the metrics are correct.

[smallzhongfeng]

Because of cross package, the property of CoordinatorMetrics cannot be referenced in HealthcheckCoordinatorgrpcTest, so I added test cases to SimpleclusterManagerTest.

[jerqi]

Thanks @smallzhongfeng ,LGTM

[smallzhongfeng]

Thanks for your review. @jerqi