chore(refactor): refactor scheduler for ZFS-LocalPV

Signed-off-by: Pawan <pawan@mayadata.io>

pkg/driver/controller.go

@@ -33,6 +33,7 @@ import (
 	errors "github.com/openebs/zfs-localpv/pkg/common/errors"
 	"github.com/openebs/zfs-localpv/pkg/common/helpers"
 	csipayload "github.com/openebs/zfs-localpv/pkg/response"
+	schd "github.com/openebs/zfs-localpv/pkg/scheduler"
 	analytics "github.com/openebs/zfs-localpv/pkg/usage"
 	zfs "github.com/openebs/zfs-localpv/pkg/zfs"
 )
@@ -126,7 +127,13 @@ func CreateZFSVolume(req *csi.CreateVolumeRequest) (string, error) {
 
 	vtype := zfs.GetVolumeType(fstype)
 
-	selected := scheduler(req.AccessibilityRequirements, schld, pool)
+	err, nmap := getNodeMap(schld, pool)
+	if err != nil {
+		return "", status.Errorf(codes.Internal, "get node map failed : %s", err.Error())
+	}
+
+	// run the scheduler
+	selected := schd.Scheduler(req, nmap)
 
 	if len(selected) == 0 {
 		return "", status.Error(codes.Internal, "scheduler failed")

pkg/driver/schd_helper.go

@@ -0,0 +1,67 @@
+/*
+Copyright 2020 The OpenEBS Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package driver
+
+import (
+	"github.com/openebs/zfs-localpv/pkg/builder/volbuilder"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+
+	zfs "github.com/openebs/zfs-localpv/pkg/zfs"
+)
+
+// scheduling algorithm constants
+const (
+	// pick the node where less volumes are provisioned for the given pool
+	// this will be the default scheduler when none provided
+	VolumeWeighted = "VolumeWeighted"
+)
+
+// getVolumeWeightedMap goes through all the pools on all the nodes
+// and creats the node mapping of the volume for all the nodes.
+// It returns a map which has nodes as key and volumes present
+// on the nodes as corresponding value.
+func getVolumeWeightedMap(pool string) (error, map[string]int64) {
+	nmap := map[string]int64{}
+
+	zvlist, err := volbuilder.NewKubeclient().
+		WithNamespace(zfs.OpenEBSNamespace).
+		List(metav1.ListOptions{})
+
+	if err != nil {
+		return err, nmap
+	}
+
+	// create the map of the volume count
+	// for the given pool
+	for _, zv := range zvlist.Items {
+		if zv.Spec.PoolName == pool {
+			nmap[zv.Spec.OwnerNodeID]++
+		}
+	}
+
+	return nil, nmap
+}
+
+// getNodeMap returns the node mapping for the given scheduling algorithm
+func getNodeMap(schd string, pool string) (error, map[string]int64) {
+	switch schd {
+	case VolumeWeighted:
+		return getVolumeWeightedMap(pool)
+	}
+	// return VolumeWeighted(default) if not specified
+	return getVolumeWeightedMap(pool)
+}

pkg/driver/scheduler.go → pkg/scheduler/scheduler.go

@@ -14,29 +14,19 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-package driver
+package scheduler
 
 import (
 	"math"
 
 	"github.com/container-storage-interface/spec/lib/go/csi"
-	"github.com/openebs/zfs-localpv/pkg/builder/volbuilder"
 	k8sapi "github.com/openebs/zfs-localpv/pkg/client/k8s/v1alpha1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/klog"
-
-	zfs "github.com/openebs/zfs-localpv/pkg/zfs"
-)
-
-// scheduling algorithm constants
-const (
-	// pick the node where less volumes are provisioned for the given pool
-	// this will be the default scheduler when none provided
-	VolumeWeighted = "VolumeWeighted"
 )
 
-// GetNodeList gets the nodelist which satisfies the topology info
-func GetNodeList(topo *csi.TopologyRequirement) ([]string, error) {
+// getNodeList gets the nodelist which satisfies the topology info
+func getNodeList(topo *csi.TopologyRequirement) ([]string, error) {
 
 	var nodelist []string
 
@@ -64,54 +54,34 @@ func GetNodeList(topo *csi.TopologyRequirement) ([]string, error) {
 	return nodelist, nil
 }
 
-// volumeWeightedScheduler goes through all the pools on the nodes mentioned
-// in the topology and picks the node which has less volume on
-// the given zfs pool.
-func volumeWeightedScheduler(nodelist []string, pool string) string {
+// runScheduler goes through the node mapping
+// in the topology and picks the node which is less weighted
+func runScheduler(nodelist []string, nmap map[string]int64) string {
 	var selected string
 
-	zvlist, err := volbuilder.NewKubeclient().
-		WithNamespace(zfs.OpenEBSNamespace).
-		List(metav1.ListOptions{})
-
-	if err != nil {
-		return ""
-	}
-
-	volmap := map[string]int{}
+	var weight int64 = math.MaxInt64
 
-	// create the map of the volume count
-	// for the given pool
-	for _, zv := range zvlist.Items {
-		if zv.Spec.PoolName == pool {
-			volmap[zv.Spec.OwnerNodeID]++
-		}
-	}
-
-	var numVol int = math.MaxInt32
-
-	// schedule it on the node which has less
-	// number of volume for the given pool
+	// schedule it on the node which has less weight
 	for _, node := range nodelist {
-		if volmap[node] < numVol {
+		if nmap[node] < weight {
 			selected = node
-			numVol = volmap[node]
+			weight = nmap[node]
 		}
 	}
 	return selected
 }
 
-// scheduler schedules the PV as per topology constraints for
-// the given zfs pool.
-func scheduler(topo *csi.TopologyRequirement, schld string, pool string) string {
-
+// Scheduler schedules the PV as per topology constraints for
+// the given node weight.
+func Scheduler(req *csi.CreateVolumeRequest, nmap map[string]int64) string {
+	topo := req.AccessibilityRequirements
 	if topo == nil ||
 		len(topo.Preferred) == 0 {
 		klog.Errorf("scheduler: topology information not provided")
 		return ""
 	}
 
-	nodelist, err := GetNodeList(topo)
+	nodelist, err := getNodeList(topo)
 	if err != nil {
 		klog.Errorf("scheduler: can not get the nodelist err : %v", err.Error())
 		return ""
@@ -125,12 +95,5 @@ func scheduler(topo *csi.TopologyRequirement, schld string, pool string) string
 		return nodelist[0]
 	}
 
-	switch schld {
-	case VolumeWeighted:
-		return volumeWeightedScheduler(nodelist, pool)
-	default:
-		return volumeWeightedScheduler(nodelist, pool)
-	}
-
-	return ""
+	return runScheduler(nodelist, nmap)
 }