The prometheus metrics refractoring (#8003)

The measures are consolidated to the following metrics

- `disk_storage_used` : Disk space used by the disk.
- `disk_storage_available`: Available disk space left on the disk.
- `disk_storage_total`: Total disk space on the disk.
- `disks_offline`: Total number of offline disks in current MinIO instance.
- `disks_total`: Total number of disks in current MinIO instance.
- `s3_requests_total`: Total number of s3 requests in current MinIO instance.
- `s3_errors_total`: Total number of errors in s3 requests in current MinIO instance.
- `s3_requests_current`: Total number of active s3 requests in current MinIO instance.
- `internode_rx_bytes_total`: Total number of internode bytes received by current MinIO server instance.
- `internode_tx_bytes_total`: Total number of bytes sent to the other nodes by current MinIO server instance.
- `s3_rx_bytes_total`: Total number of s3 bytes received by current MinIO server instance.
- `s3_tx_bytes_total`: Total number of s3 bytes sent by current MinIO server instance.
- `minio_version_info`: Current MinIO version with commit-id.
- `s3_ttfb_seconds_bucket`: Histogram that holds the latency information of the requests.

And this PR also modifies the current StorageInfo queries

- Decouples StorageInfo from ServerInfo .
- StorageInfo is enhanced to give endpoint information.

NOTE: ADMIN API VERSION IS BUMPED UP IN THIS PR

Fixes #7873

cmd/xl-v1.go

@@ -19,9 +19,12 @@ package cmd
 import (
 	"context"
 	"sort"
+	"strings"
 
 	"github.com/minio/minio/cmd/logger"
 	"github.com/minio/minio/pkg/bpool"
+	"github.com/minio/minio/pkg/madmin"
+	xnet "github.com/minio/minio/pkg/net"
 	"github.com/minio/minio/pkg/sync/errgroup"
 )
 
@@ -69,7 +72,7 @@ func (d byDiskTotal) Less(i, j int) bool {
 }
 
 // getDisksInfo - fetch disks info across all other storage API.
-func getDisksInfo(disks []StorageAPI) (disksInfo []DiskInfo, onlineDisks int, offlineDisks int) {
+func getDisksInfo(disks []StorageAPI) (disksInfo []DiskInfo, onlineDisks, offlineDisks madmin.BackendDisks) {
 	disksInfo = make([]DiskInfo, len(disks))
 
 	g := errgroup.WithNErrs(len(disks))
@@ -94,13 +97,33 @@ func getDisksInfo(disks []StorageAPI) (disksInfo []DiskInfo, onlineDisks int, of
 		}, index)
 	}
 
-	// Wait for the routines.
-	for _, err := range g.Wait() {
+	getPeerAddress := func(diskPath string) (string, error) {
+		hostPort := strings.Split(diskPath, SlashSeparator)[0]
+		thisAddr, err := xnet.ParseHost(hostPort)
 		if err != nil {
-			offlineDisks++
+			return "", err
+		}
+		return thisAddr.String(), nil
+	}
+
+	onlineDisks = make(madmin.BackendDisks)
+	offlineDisks = make(madmin.BackendDisks)
+	// Wait for the routines.
+	for i, err := range g.Wait() {
+		peerAddr, pErr := getPeerAddress(disksInfo[i].RelativePath)
+		if pErr != nil {
 			continue
 		}
-		onlineDisks++
+		if _, ok := offlineDisks[peerAddr]; !ok {
+			offlineDisks[peerAddr] = 0
+		}
+		if _, ok := onlineDisks[peerAddr]; !ok {
+			onlineDisks[peerAddr] = 0
+		}
+		if err != nil {
+			offlineDisks[peerAddr]++
+		}
+		onlineDisks[peerAddr]++
 	}
 
 	// Success.
@@ -134,17 +157,23 @@ func getStorageInfo(disks []StorageAPI) StorageInfo {
 	}
 
 	// Combine all disks to get total usage
-	var used, total, available uint64
-	for _, di := range validDisksInfo {
-		used = used + di.Used
-		total = total + di.Total
-		available = available + di.Free
+	usedList := make([]uint64, len(validDisksInfo))
+	totalList := make([]uint64, len(validDisksInfo))
+	availableList := make([]uint64, len(validDisksInfo))
+	mountPaths := make([]string, len(validDisksInfo))
+
+	for i, di := range validDisksInfo {
+		usedList[i] = di.Used
+		totalList[i] = di.Total
+		availableList[i] = di.Free
+		mountPaths[i] = di.RelativePath
 	}
 
 	storageInfo := StorageInfo{
-		Used:      used,
-		Total:     total,
-		Available: available,
+		Used:       usedList,
+		Total:      totalList,
+		Available:  availableList,
+		MountPaths: mountPaths,
 	}
 
 	storageInfo.Backend.Type = BackendErasure