fix prometheus calculation of offline disks per instance

[harshavardhana]

Description

fix Prometheus calculation of offline disks per instance

Motivation and Context

This was a regression introduced in 9baeda7 for Prometheus
calculation of offline disks which should be local to
an instance.

fixes #9742

How to test this PR?

Just start a local distributed setup and you can observe
remote nodes considered as offline in Prometheus

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• Fixes a regression yes introduced in 9baeda7
• Documentation needed
• Unit tests needed
• Functional tests needed (If yes, add mint PR # here: )

[minio-trusted]

Mint Automation

Test	Result
mint-xl.sh	✔️
mint-large-bucket.sh	✔️
mint-fs.sh	✔️
mint-dist-xl.sh	✔️
mint-gateway-s3.sh	✔️
mint-gateway-nas.sh	✔️
mint-gateway-azure.sh	❌ more...

9744-2ca3ab2/mint-gateway-azure.sh.log:

Running with
SERVER_ENDPOINT:      minio-dev4.minio.io:31788
ACCESS_KEY:           minioazure
SECRET_KEY:           ***REDACTED***
ENABLE_HTTPS:         0
SERVER_REGION:        us-east-1
MINT_DATA_DIR:        /mint/data
MINT_MODE:            full
ENABLE_VIRTUAL_STYLE: 0

To get logs, run 'docker cp 61141bc79735:/mint/log /tmp/mint-logs'

(1/15) Running aws-sdk-go tests ... done in 8 seconds
(2/15) Running aws-sdk-java tests ... done in 1 seconds
(3/15) Running aws-sdk-php tests ... done in 37 seconds
(4/15) Running aws-sdk-ruby tests ... done in 15 seconds
(5/15) Running awscli tests ... done in 2 minutes and 43 seconds
(6/15) Running healthcheck tests ... done in 0 seconds
(7/15) Running mc tests ... done in 3 minutes and 15 seconds
(8/15) Running minio-dotnet tests ... done in 1 minutes and 25 seconds
(9/15) Running minio-go tests ... done in 3 minutes and 46 seconds
(10/15) Running minio-java tests ... FAILED in 24 minutes and 8 seconds
error occurred
ErrorResponse(code = BucketNotEmpty, message = The bucket you tried to delete is not empty, bucketName = minio-java-test-1b2m388, objectName = null, resource = /minio-java-test-1b2m388, requestId = 1613E4E88CB00F62, hostId = 1823ba82-510c-4fc7-887d-8c64609d009c)
request={method=DELETE, url=http://minio-dev4.minio.io:31788/minio-java-test-1b2m388, headers=Host: minio-dev4.minio.io:31788
Accept-Encoding: identity
User-Agent: MinIO (amd64; amd64) minio-java/dev
Content-MD5: 1B2M2Y8AsgTpgAmY7PhCfg==
x-amz-content-sha256: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
x-amz-date: 20200530T192620Z
Authorization: AWS4-HMAC-SHA256 Credential=*REDACTED*/20200530/us-east-1/s3/aws4_request, SignedHeaders=accept-encoding;content-md5;host;x-amz-content-sha256;x-amz-date, Signature=*REDACTED*
}
response={code=409, headers=Accept-Ranges: bytes
Content-Length: 328
Content-Security-Policy: block-all-mixed-content
Content-Type: application/xml
Server: MinIO/DEVELOPMENT.GOGET
Vary: Origin
X-Amz-Request-Id: 1613E4E88CB00F62
X-Xss-Protection: 1; mode=block
Date: Sat, 30 May 2020 19:26:20 GMT
}

	at io.minio.MinioClient.execute(MinioClient.java:1211)
	at io.minio.MinioClient.execute(MinioClient.java:1236)
	at io.minio.MinioClient.executeDelete(MinioClient.java:1366)
	at io.minio.MinioClient.removeBucket(MinioClient.java:3686)
	at FunctionalTest.teardown(FunctionalTest.java:414)
	at FunctionalTest.runTests(FunctionalTest.java:4122)
	at FunctionalTest.main(FunctionalTest.java:4192)
(10/15) Running minio-js tests ... done in 2 minutes and 39 seconds
(11/15) Running minio-py tests ... done in 9 minutes and 52 seconds
(12/15) Running s3cmd tests ... done in 1 minutes and 21 seconds
(13/15) Running s3select tests ... done in 1 minutes and 0 seconds
(14/15) Running security tests ... done in 0 seconds

Executed 14 out of 15 tests successfully.

Deleting image on docker hub
Deleting image locally

[Praveenrajmani]

Tested and LGTM

[vadmeste]

LGTM, not tested !