fix: re-implement cluster healthcheck (#10101)

cmd/erasure-sets.go

@@ -1633,9 +1633,10 @@ func (s *erasureSets) GetMetrics(ctx context.Context) (*Metrics, error) {
 	return &Metrics{}, NotImplemented{}
 }
 
-// IsReady - Returns true if atleast n/2 disks (read quorum) are online
-func (s *erasureSets) IsReady(_ context.Context) bool {
-	return false
+// Health shouldn't be called directly - will panic
+func (s *erasureSets) Health(ctx context.Context, _ HealthOptions) HealthResult {
+	logger.CriticalIf(ctx, NotImplemented{})
+	return HealthResult{}
 }
 
 // maintainMRFList gathers the list of successful partial uploads

cmd/erasure-zones.go

@@ -2007,29 +2007,49 @@ func (z *erasureZones) getZoneAndSet(id string) (int, int, error) {
 	return 0, 0, fmt.Errorf("DiskID(%s) %w", id, errDiskNotFound)
 }
 
-// IsReady - Returns true, when all the erasure sets are writable.
-func (z *erasureZones) IsReady(ctx context.Context) bool {
+// HealthOptions takes input options to return sepcific information
+type HealthOptions struct {
+	Maintenance bool
+}
+
+// HealthResult returns the current state of the system, also
+// additionally with any specific heuristic information which
+// was queried
+type HealthResult struct {
+	Healthy       bool
+	ZoneID, SetID int
+	WriteQuorum   int
+}
+
+// Health - returns current status of the object layer health,
+// provides if write access exists across sets, additionally
+// can be used to query scenarios if health may be lost
+// if this node is taken down by an external orchestrator.
+func (z *erasureZones) Health(ctx context.Context, opts HealthOptions) HealthResult {
 	erasureSetUpCount := make([][]int, len(z.zones))
 	for i := range z.zones {
 		erasureSetUpCount[i] = make([]int, len(z.zones[i].sets))
 	}
 
 	diskIDs := globalNotificationSys.GetLocalDiskIDs(ctx)
+	if !opts.Maintenance {
+		diskIDs = append(diskIDs, getLocalDiskIDs(z))
+	}
 
-	diskIDs = append(diskIDs, getLocalDiskIDs(z)...)
-
-	for _, id := range diskIDs {
-		zoneIdx, setIdx, err := z.getZoneAndSet(id)
-		if err != nil {
-			logger.LogIf(ctx, err)
-			continue
+	for _, localDiskIDs := range diskIDs {
+		for _, id := range localDiskIDs {
+			zoneIdx, setIdx, err := z.getZoneAndSet(id)
+			if err != nil {
+				logger.LogIf(ctx, err)
+				continue
+			}
+			erasureSetUpCount[zoneIdx][setIdx]++
 		}
-		erasureSetUpCount[zoneIdx][setIdx]++
 	}
 
 	for zoneIdx := range erasureSetUpCount {
 		parityDrives := globalStorageClass.GetParityForSC(storageclass.STANDARD)
-		diskCount := len(z.zones[zoneIdx].format.Erasure.Sets[0])
+		diskCount := z.zones[zoneIdx].drivesPerSet
 		if parityDrives == 0 {
 			parityDrives = getDefaultParityBlocks(diskCount)
 		}
@@ -2042,11 +2062,18 @@ func (z *erasureZones) IsReady(ctx context.Context) bool {
 			if erasureSetUpCount[zoneIdx][setIdx] < writeQuorum {
 				logger.LogIf(ctx, fmt.Errorf("Write quorum lost on zone: %d, set: %d, expected write quorum: %d",
 					zoneIdx, setIdx, writeQuorum))
-				return false
+				return HealthResult{
+					Healthy:     false,
+					ZoneID:      zoneIdx,
+					SetID:       setIdx,
+					WriteQuorum: writeQuorum,
+				}
 			}
 		}
 	}
-	return true
+	return HealthResult{
+		Healthy: true,
+	}
 }
 
 // PutObjectTags - replace or add tags to an existing object

cmd/erasure.go

@@ -391,8 +391,8 @@ func (er erasureObjects) crawlAndGetDataUsage(ctx context.Context, buckets []Buc
 	return nil
 }
 
-// IsReady - shouldn't be called will panic.
-func (er erasureObjects) IsReady(ctx context.Context) bool {
+// Health shouldn't be called directly - will panic
+func (er erasureObjects) Health(ctx context.Context, _ HealthOptions) HealthResult {
 	logger.CriticalIf(ctx, NotImplemented{})
-	return true
+	return HealthResult{}
 }

cmd/fs-v1.go

@@ -1557,11 +1557,12 @@ func (fs *FSObjects) IsTaggingSupported() bool {
 	return true
 }
 
-// IsReady - Check if the backend disk is ready to accept traffic.
-func (fs *FSObjects) IsReady(_ context.Context) bool {
+// Health returns health of the object layer
+func (fs *FSObjects) Health(ctx context.Context, opts HealthOptions) HealthResult {
 	if _, err := os.Stat(fs.fsPath); err != nil {
-		return false
+		return HealthResult{}
+	}
+	return HealthResult{
+		Healthy: newObjectLayerFn() != nil,
 	}
-
-	return newObjectLayerFn() != nil
 }

cmd/gateway-unsupported.go

@@ -250,7 +250,7 @@ func (a GatewayUnsupported) IsCompressionSupported() bool {
 	return false
 }
 
-// IsReady - No Op.
-func (a GatewayUnsupported) IsReady(_ context.Context) bool {
-	return false
+// Health - No Op.
+func (a GatewayUnsupported) Health(_ context.Context, _ HealthOptions) HealthResult {
+	return HealthResult{}
 }

cmd/gateway/azure/gateway-azure.go

@@ -1436,8 +1436,3 @@ func (a *azureObjects) DeleteBucketPolicy(ctx context.Context, bucket string) er
 func (a *azureObjects) IsCompressionSupported() bool {
 	return false
 }
-
-// IsReady returns whether the layer is ready to take requests.
-func (a *azureObjects) IsReady(ctx context.Context) bool {
-	return minio.IsBackendOnline(ctx, a.httpClient, a.endpoint)
-}

cmd/gateway/gcs/gateway-gcs.go

@@ -1508,8 +1508,3 @@ func (l *gcsGateway) DeleteBucketPolicy(ctx context.Context, bucket string) erro
 func (l *gcsGateway) IsCompressionSupported() bool {
 	return false
 }
-
-// IsReady returns whether the layer is ready to take requests.
-func (l *gcsGateway) IsReady(ctx context.Context) bool {
-	return minio.IsBackendOnline(ctx, l.httpClient, "https://storage.googleapis.com")
-}

cmd/gateway/hdfs/gateway-hdfs.go

@@ -786,9 +786,3 @@ func (n *hdfsObjects) AbortMultipartUpload(ctx context.Context, bucket, object,
 	}
 	return hdfsToObjectErr(ctx, n.clnt.Remove(n.hdfsPathJoin(minioMetaTmpBucket, uploadID)), bucket, object, uploadID)
 }
-
-// IsReady returns whether the layer is ready to take requests.
-func (n *hdfsObjects) IsReady(ctx context.Context) bool {
-	si, _ := n.StorageInfo(ctx, false)
-	return si.Backend.GatewayOnline
-}

cmd/gateway/nas/gateway-nas.go

@@ -121,12 +121,6 @@ type nasObjects struct {
 	minio.ObjectLayer
 }
 
-// IsReady returns whether the layer is ready to take requests.
-func (n *nasObjects) IsReady(ctx context.Context) bool {
-	si, _ := n.StorageInfo(ctx, false)
-	return si.Backend.GatewayOnline
-}
-
 func (n *nasObjects) IsTaggingSupported() bool {
 	return true
 }

cmd/gateway/s3/gateway-s3.go

@@ -755,11 +755,6 @@ func (l *s3Objects) IsEncryptionSupported() bool {
 	return minio.GlobalKMS != nil || len(minio.GlobalGatewaySSE) > 0
 }
 
-// IsReady returns whether the layer is ready to take requests.
-func (l *s3Objects) IsReady(ctx context.Context) bool {
-	return minio.IsBackendOnline(ctx, l.HTTPClient, l.Client.EndpointURL().String())
-}
-
 func (l *s3Objects) IsTaggingSupported() bool {
 	return true
 }

cmd/healthcheck-handler.go

@@ -35,8 +35,17 @@ func ClusterCheckHandler(w http.ResponseWriter, r *http.Request) {
 	ctx, cancel := context.WithTimeout(ctx, globalAPIConfig.getReadyDeadline())
 	defer cancel()
 
-	if !objLayer.IsReady(ctx) {
-		writeResponse(w, http.StatusServiceUnavailable, nil, mimeNone)
+	opts := HealthOptions{Maintenance: r.URL.Query().Get("maintenance") == "true"}
+	result := objLayer.Health(ctx, opts)
+	if !result.Healthy {
+		// As a maintenance call we are purposefully asked to be taken
+		// down, this is for orchestrators to know if we can safely
+		// take this server down, return appropriate error.
+		if opts.Maintenance {
+			writeResponse(w, http.StatusPreconditionFailed, nil, mimeNone)
+		} else {
+			writeResponse(w, http.StatusServiceUnavailable, nil, mimeNone)
+		}
 		return
 	}
 

cmd/notification.go

@@ -1164,26 +1164,21 @@ func (sys *NotificationSys) ServerInfo() []madmin.ServerProperties {
 }
 
 // GetLocalDiskIDs - return disk ids of the local disks of the peers.
-func (sys *NotificationSys) GetLocalDiskIDs(ctx context.Context) []string {
-	var diskIDs []string
-	var mu sync.Mutex
-
+func (sys *NotificationSys) GetLocalDiskIDs(ctx context.Context) (localDiskIDs [][]string) {
+	localDiskIDs = make([][]string, len(sys.peerClients))
 	var wg sync.WaitGroup
-	for _, client := range sys.peerClients {
+	for idx, client := range sys.peerClients {
 		if client == nil {
 			continue
 		}
 		wg.Add(1)
-		go func(client *peerRESTClient) {
+		go func(idx int, client *peerRESTClient) {
 			defer wg.Done()
-			ids := client.GetLocalDiskIDs(ctx)
-			mu.Lock()
-			diskIDs = append(diskIDs, ids...)
-			mu.Unlock()
-		}(client)
+			localDiskIDs[idx] = client.GetLocalDiskIDs(ctx)
+		}(idx, client)
 	}
 	wg.Wait()
-	return diskIDs
+	return localDiskIDs
 }
 
 // NewNotificationSys - creates new notification system object.

cmd/object-api-interface.go

@@ -133,8 +133,8 @@ type ObjectLayer interface {
 	// Backend related metrics
 	GetMetrics(ctx context.Context) (*Metrics, error)
 
-	// Check Readiness
-	IsReady(ctx context.Context) bool
+	// Returns health of the backend
+	Health(ctx context.Context, opts HealthOptions) HealthResult
 
 	// ObjectTagging operations
 	PutObjectTags(context.Context, string, string, string, ObjectOptions) error