Support drive anti-affinity for volumes (#823)

Some optimal setups would require volumes to be allocated on unique
disks. ie, not more than one volume per disk.
    
By default, the volume scheduling algorithm choses the drive based on
most free capacity. This will end up allocating more than one volumes
per disk.
    
This PR provides a way for such optimal setups, by using the storage
class parameters. Using a storage class with
`directpv.min.io/volume-claim-id: XXX` parameter enables unique
allocation for PVCs. This unique allocation id enables the one-to-one
cardinality for the drives and volumes.

Co-authored-by: Bala FA <bala@minio.io>

docs/tools/create-storage-class.sh

@@ -18,27 +18,40 @@
 
 set -e -C -o pipefail
 
-declare NAME DRIVE_LABEL
+declare NAME
+declare -a DRIVE_LABELS
 
 function init() {
-    if [[ $# -ne 2 ]]; then
+    if [[ $# -lt 2 ]]; then
         cat <<EOF
 USAGE:
-  create-storage-class.sh <NAME> <DRIVE-LABEL>
+  create-storage-class.sh <NAME> <DRIVE-LABELS> ...
 
 ARGUMENTS:
   NAME           new storage class name.
-  DRIVE-LABEL    drive labels to be attached.
+  DRIVE-LABELS   drive labels to be attached.
 
 EXAMPLE:
   # Create new storage class 'fast-tier-storage' with drive labels 'directpv.min.io/tier: fast'
   $ create-storage-class.sh fast-tier-storage 'directpv.min.io/tier: fast'
+
+  # Create new storage class with more than one drive label
+  $ create-storage-class.sh fast-tier-unique 'directpv.min.io/tier: fast' 'directpv.min.io/volume-claim-id: bcea279a-df70-4d23-be41-9490f9933004'
 EOF
         exit 255
     fi
 
     NAME="$1"
-    DRIVE_LABEL="$2"
+    shift
+    DRIVE_LABELS=( "$@" )
+
+    for val in "${DRIVE_LABELS[@]}"; do
+        if [[ "$val" =~ ^directpv.min.io/volume-claim-id:.* ]] && ! [[ "${val#directpv.min.io/volume-claim-id: }" =~ ^[a-fA-F0-9]{8}-[a-fA-F0-9]{4}-[a-fA-F0-9]{4}-[a-fA-F0-9]{4}-[a-fA-F0-9]{12}$ ]];
+        then
+            echo "invalid uuid value set for volume-claim-id; please set a valid uuid based on [RFC 4122]"
+            exit 255
+        fi
+    done
 
     if ! which kubectl >/dev/null 2>&1; then
         echo "kubectl not found; please install"
@@ -67,7 +80,7 @@ metadata:
   name: ${NAME}
 parameters:
   fstype: xfs
-  ${DRIVE_LABEL}
+$(printf '  %s\n' "${DRIVE_LABELS[@]}")
 provisioner: directpv-min-io
 reclaimPolicy: Delete
 volumeBindingMode: WaitForFirstConsumer

docs/volume-scheduling.md

@@ -11,6 +11,7 @@ DirectPV CSI controller selects suitable drive for `CreateVolume` request like b
    a. By requested capacity
    b. By access-tier if requested
    c. By topology constraints if requested
+   d. By volume claim ID if requested
 4. In the process of step (3), if more than one drive is selected, the maximum free capacity drive is picked.
 5. If step (4) picks up more than one drive, a drive is randomly selected.
 6. Finally the selected drive is updated with requested volume information.
@@ -51,14 +52,17 @@ DirectPV CSI controller selects suitable drive for `CreateVolume` request like b
       |           ╭╌╌╌╌╌╌╌V╌╌╌╌╌╌╌╮   |     │ if requested? │
       |     No    │ Is more than  │   |     ╰╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╯
       +-----------│   one drive   │   |             | Yes
-                  │    matched?   │   |     ┌───────V───────┐
-                  ╰╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╯   |     │   Append to   │
-                          | Yes       +<----│ matched drives│
-                  ┌───────V───────┐         └───────────────┘
-                  │     Return    │
-                  │    Randomly   │
-                  │ selected drive│
-                  └───────────────┘
+                  │    matched?   │   |     ╭╌╌╌╌╌╌╌V╌╌╌╌╌╌╌╮
+                  ╰╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╯   |     │   Match by    │
+                          | Yes       | Yes │ volume claim  │
+                  ┌───────V───────┐   |<----│      ID       │
+                  │     Return    │   |     │ if requested? │
+                  │    Randomly   │   |     ╰╌╌╌╌╌╌╌╌╌╌╌╌╌╌╌╯
+                  │ selected drive│   |             | No
+                  └───────────────┘   |     ┌───────V───────┐
+                                      |     │   Append to   │
+                                      +<----│ matched drives│
+                                            └───────────────┘
 ```
 
 ## Customizing drive selection
@@ -92,3 +96,84 @@ spec:
       storage: 8Mi
 EOF
 ```
+
+### Unique drive selection
+
+The default free capacity based drive selection leads to allocate more than one volume in a single drive for StatefulSet deployments which lacks performance and high availability for application like MinIO object storage. To overcome this behavior, DirectPV provides a way to allocate one volume per drive. This feature needs to be set by having custom storage class with label 'directpv.min.io/volume-claim-id'. Below is an example to create custom storage class using [create-storage-class.sh script](../tools/create-storage-class.sh):
+
+```sh
+create-storage-class.sh tenant-1-storage 'directpv.min.io/volume-claim-id: 555e99eb-e255-4407-83e3-fc443bf20f86'
+```
+
+This custom storage class has to be used in your StatefulSet deployment. Below is an example to deploy MinIO object storage
+
+```yaml
+kind: Service
+apiVersion: v1
+metadata:
+  name: minio
+  labels:
+    app: minio
+spec:
+  selector:
+    app: minio
+  ports:
+    - name: minio
+      port: 9000
+
+---
+
+apiVersion: apps/v1
+kind: StatefulSet
+metadata:
+  name: minio
+  labels:
+    app: minio
+spec:
+  serviceName: "minio"
+  replicas: 2
+  selector:
+    matchLabels:
+      app: minio
+  template:
+    metadata:
+      labels:
+        app: minio
+        directpv.min.io/organization: minio
+        directpv.min.io/app: minio-example
+        directpv.min.io/tenant: tenant-1
+    spec:
+      containers:
+      - name: minio
+        image: minio/minio
+        env:
+        - name: MINIO_ACCESS_KEY
+          value: minio
+        - name: MINIO_SECRET_KEY
+          value: minio123
+        volumeMounts:
+        - name: minio-data-1
+          mountPath: /data1
+        - name: minio-data-2
+          mountPath: /data2
+        args:
+        - "server"
+        - "http://minio-{0...1}.minio.default.svc.cluster.local:9000/data{1...2}"
+  volumeClaimTemplates:
+  - metadata:
+      name: minio-data-1
+    spec:
+      storageClassName: tenant-1-storage
+      accessModes: [ "ReadWriteOnce" ]
+      resources:
+        requests:
+          storage: 16Mi
+  - metadata:
+      name: minio-data-2
+    spec:
+      storageClassName: tenant-1-storage
+      accessModes: [ "ReadWriteOnce" ]
+      resources:
+        requests:
+          storage: 16Mi
+```

pkg/apis/directpv.min.io/types/label.go

@@ -79,6 +79,15 @@ const (
 
 	// SuspendLabelKey denotes if the volume is suspended.
 	SuspendLabelKey LabelKey = consts.GroupName + "/suspend"
+
+	// VolumeClaimIDLabelKey label key to denote the unique allocation of drives for volumes
+	VolumeClaimIDLabelKey LabelKey = consts.GroupName + "/volume-claim-id"
+
+	// VolumeClaimIDLabelKeyPrefix label key prefix for volume claim id to be set on the drive
+	VolumeClaimIDLabelKeyPrefix = consts.GroupName + "/volume-claim-id-"
+
+	// ClaimIDLabelKey label key to denote the claim id of the volumes
+	ClaimIDLabelKey LabelKey = consts.GroupName + "/claim-id"
 )
 
 // LabelValue is a type definition for label value

pkg/apis/directpv.min.io/v1beta1/drive.go

@@ -17,6 +17,7 @@
 package v1beta1
 
 import (
+	"strconv"
 	"strings"
 
 	"github.com/minio/directpv/pkg/apis/directpv.min.io/types"
@@ -221,6 +222,30 @@ func (drive DirectPVDrive) GetNodeID() types.NodeID {
 	return types.NodeID(drive.getLabel(types.NodeLabelKey))
 }
 
+// HasVolumeClaimID checks if the provided volume claim id is set on the drive.
+func (drive *DirectPVDrive) HasVolumeClaimID(claimID string) bool {
+	if claimID == "" {
+		return false
+	}
+	return drive.GetLabels()[types.VolumeClaimIDLabelKeyPrefix+claimID] == strconv.FormatBool(true)
+}
+
+// SetVolumeClaimID sets the provided claim id on the drive.
+func (drive *DirectPVDrive) SetVolumeClaimID(claimID string) {
+	if claimID == "" {
+		return
+	}
+	drive.SetLabel(types.LabelKey(types.VolumeClaimIDLabelKeyPrefix+claimID), types.LabelValue(strconv.FormatBool(true)))
+}
+
+// RemoveVolumeClaimID removes the volume claim id label.
+func (drive *DirectPVDrive) RemoveVolumeClaimID(claimID string) {
+	if claimID == "" {
+		return
+	}
+	drive.RemoveLabel(types.LabelKey(types.VolumeClaimIDLabelKeyPrefix + claimID))
+}
+
 // SetLabel sets label to this drive.
 func (drive *DirectPVDrive) SetLabel(key types.LabelKey, value types.LabelValue) bool {
 	values := drive.GetLabels()

pkg/apis/directpv.min.io/v1beta1/volume.go

@@ -293,6 +293,19 @@ func (volume DirectPVVolume) IsSuspended() bool {
 	return string(volume.getLabel(types.SuspendLabelKey)) == strconv.FormatBool(true)
 }
 
+// SetClaimID sets the provided claim id on the volume.
+func (volume *DirectPVVolume) SetClaimID(claimID string) {
+	if claimID == "" {
+		return
+	}
+	volume.SetLabel(types.ClaimIDLabelKey, types.LabelValue(claimID))
+}
+
+// GetClaimID gets the claim id set on the volume.
+func (volume *DirectPVVolume) GetClaimID() string {
+	return string(volume.getLabel(types.ClaimIDLabelKey))
+}
+
 // +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
 
 // DirectPVVolumeList denotes list of volumes.

pkg/csi/controller/server.go

@@ -19,6 +19,7 @@ package controller
 import (
 	"context"
 	"fmt"
+	"regexp"
 
 	"github.com/container-storage-interface/spec/lib/go/csi"
 	"github.com/dustin/go-humanize"
@@ -32,6 +33,8 @@ import (
 	"k8s.io/klog/v2"
 )
 
+var volumeClaimIDRegex = regexp.MustCompile("^[a-fA-F0-9]{8}-[a-fA-F0-9]{4}-[a-fA-F0-9]{4}-[a-fA-F0-9]{4}-[a-fA-F0-9]{12}$")
+
 /*  Volume Lifecycle
  *
  *  Creation
@@ -145,11 +148,18 @@ func (c *Server) CreateVolume(ctx context.Context, req *csi.CreateVolumeRequest)
 		return nil, status.Errorf(codes.InvalidArgument, "unsupported filesystem type %v for volume %v", req.GetVolumeCapabilities()[0].GetMount().GetFsType(), name)
 	}
 
+	var volumeClaimID string
 	for key, value := range req.GetParameters() {
-		if key == string(directpvtypes.AccessTierLabelKey) {
+		switch key {
+		case string(directpvtypes.AccessTierLabelKey):
 			if _, err := directpvtypes.StringsToAccessTiers(value); err != nil {
 				return nil, status.Errorf(codes.InvalidArgument, "unknown access-tier %v for volume %v; %v", value, name, err)
 			}
+		case string(directpvtypes.VolumeClaimIDLabelKey):
+			if !volumeClaimIDRegex.MatchString(value) {
+				return nil, status.Errorf(codes.InvalidArgument, "invalid volume claim ID %v; ", value)
+			}
+			volumeClaimID = value
 		}
 	}
 
@@ -177,6 +187,7 @@ func (c *Server) CreateVolume(ctx context.Context, req *csi.CreateVolumeRequest)
 		drive.GetDriveName(),
 		size,
 	)
+	newVolume.SetClaimID(volumeClaimID)
 
 	if _, err := client.VolumeClient().Create(ctx, newVolume, metav1.CreateOptions{}); err != nil {
 		if !errors.IsAlreadyExists(err) {
@@ -206,6 +217,7 @@ func (c *Server) CreateVolume(ctx context.Context, req *csi.CreateVolumeRequest)
 	}
 
 	if drive.AddVolumeFinalizer(req.GetName()) {
+		drive.SetVolumeClaimID(volumeClaimID)
 		drive.Status.FreeCapacity -= size
 		drive.Status.AllocatedCapacity += size
 

pkg/csi/controller/utils.go

@@ -65,6 +65,11 @@ func matchDrive(drive *types.Drive, req *csi.CreateVolumeRequest) bool {
 			if len(accessTiers) > 0 && drive.GetAccessTier() != accessTiers[0] {
 				return false
 			}
+		case string(directpvtypes.VolumeClaimIDLabelKey):
+			if drive.HasVolumeClaimID(value) {
+				// Do not allocate another volume with this claim id
+				return false
+			}
 		default:
 			if labels[key] != value {
 				return false