backport of commit 0ccf942b26f8c47582f18f324114d02d0bb03a43 (#18684)

Co-authored-by: Luiz Aoqui <luiz@hashicorp.com>

scheduler/feasible.go

@@ -1237,7 +1237,8 @@ OUTER:
 }
 
 // available checks transient feasibility checkers which depend on changing conditions,
-// e.g. the health status of a plugin or driver
+// e.g. the health status of a plugin or driver, or that are not considered in node
+// computed class, e.g. host volumes.
 func (w *FeasibilityWrapper) available(option *structs.Node) bool {
 	// If we don't have any availability checks, we're available
 	if len(w.tgAvailable) == 0 {

scheduler/stack.go

@@ -259,11 +259,13 @@ func NewSystemStack(sysbatch bool, ctx Context) *SystemStack {
 	tgs := []FeasibilityChecker{
 		s.taskGroupDrivers,
 		s.taskGroupConstraint,
-		s.taskGroupHostVolumes,
 		s.taskGroupDevices,
 		s.taskGroupNetwork,
 	}
-	avail := []FeasibilityChecker{s.taskGroupCSIVolumes}
+	avail := []FeasibilityChecker{
+		s.taskGroupHostVolumes,
+		s.taskGroupCSIVolumes,
+	}
 	s.wrappedChecks = NewFeasibilityWrapper(ctx, s.source, jobs, tgs, avail)
 
 	// Filter on distinct property constraints.
@@ -406,11 +408,13 @@ func NewGenericStack(batch bool, ctx Context) *GenericStack {
 	tgs := []FeasibilityChecker{
 		s.taskGroupDrivers,
 		s.taskGroupConstraint,
-		s.taskGroupHostVolumes,
 		s.taskGroupDevices,
 		s.taskGroupNetwork,
 	}
-	avail := []FeasibilityChecker{s.taskGroupCSIVolumes}
+	avail := []FeasibilityChecker{
+		s.taskGroupHostVolumes,
+		s.taskGroupCSIVolumes,
+	}
 	s.wrappedChecks = NewFeasibilityWrapper(ctx, s.source, jobs, tgs, avail)
 
 	// Filter on distinct host constraints.

scheduler/stack_test.go

@@ -12,6 +12,7 @@ import (
 	"github.com/hashicorp/nomad/ci"
 	"github.com/hashicorp/nomad/nomad/mock"
 	"github.com/hashicorp/nomad/nomad/structs"
+	"github.com/shoenig/test/must"
 	"github.com/stretchr/testify/require"
 )
 
@@ -247,6 +248,100 @@ func TestServiceStack_Select_DriverFilter(t *testing.T) {
 	}
 }
 
+func TestServiceStack_Select_HostVolume(t *testing.T) {
+	ci.Parallel(t)
+
+	_, ctx := testContext(t)
+
+	// Create nodes with host volumes and one without.
+	node0 := mock.Node()
+
+	node1 := mock.Node()
+	node1.HostVolumes = map[string]*structs.ClientHostVolumeConfig{
+		"unique": {
+			Name: "unique",
+			Path: "/tmp/unique",
+		},
+		"per_alloc[0]": {
+			Name: "per_alloc[0]",
+			Path: "/tmp/per_alloc_0",
+		},
+	}
+	node1.ComputeClass()
+
+	node2 := mock.Node()
+	node2.HostVolumes = map[string]*structs.ClientHostVolumeConfig{
+		"per_alloc[1]": {
+			Name: "per_alloc[1]",
+			Path: "/tmp/per_alloc_1",
+		},
+	}
+	node2.ComputeClass()
+
+	// Create stack with nodes.
+	stack := NewGenericStack(false, ctx)
+	stack.SetNodes([]*structs.Node{node0, node1, node2})
+
+	job := mock.Job()
+	job.TaskGroups[0].Count = 1
+	job.TaskGroups[0].Volumes = map[string]*structs.VolumeRequest{"unique": {
+		Name:     "unique",
+		Type:     structs.VolumeTypeHost,
+		Source:   "unique",
+		PerAlloc: false,
+	}}
+	stack.SetJob(job)
+
+	// Alloc selects node with host volume 'unique'.
+	selectOptions := &SelectOptions{
+		AllocName: structs.AllocName(job.Name, job.TaskGroups[0].Name, 0),
+	}
+	option := stack.Select(job.TaskGroups[0], selectOptions)
+	must.NotNil(t, option)
+	must.Eq(t, option.Node.ID, node1.ID)
+
+	// Recreate the stack and select volumes per alloc.
+	stack = NewGenericStack(false, ctx)
+	stack.SetNodes([]*structs.Node{node0, node1, node2})
+
+	job.TaskGroups[0].Count = 3
+	job.TaskGroups[0].Volumes = map[string]*structs.VolumeRequest{"per_alloc": {
+		Name:     "per_alloc",
+		Type:     structs.VolumeTypeHost,
+		Source:   "per_alloc",
+		PerAlloc: true,
+	}}
+	stack.SetJob(job)
+
+	// First alloc selects node with host volume 'per_alloc[0]'.
+	selectOptions = &SelectOptions{
+		AllocName: structs.AllocName(job.Name, job.TaskGroups[0].Name, 0),
+	}
+	option = stack.Select(job.TaskGroups[0], selectOptions)
+	must.NotNil(t, option)
+	must.Eq(t, option.Node.ID, node1.ID)
+
+	// Second alloc selects node with host volume 'per_alloc[1]'.
+	selectOptions = &SelectOptions{
+		AllocName: structs.AllocName(job.Name, job.TaskGroups[0].Name, 1),
+	}
+	option = stack.Select(job.TaskGroups[0], selectOptions)
+	must.NotNil(t, option)
+	must.Eq(t, option.Node.ID, node2.ID)
+
+	// Third alloc must select node with host volume 'per_alloc[2]', but none
+	// of the nodes available can fulfil this requirement.
+	selectOptions = &SelectOptions{
+		AllocName: structs.AllocName(job.Name, job.TaskGroups[0].Name, 2),
+	}
+	option = stack.Select(job.TaskGroups[0], selectOptions)
+	must.Nil(t, option)
+
+	metrics := ctx.Metrics()
+	must.MapLen(t, 1, metrics.ConstraintFiltered)
+	must.Eq(t, metrics.ConstraintFiltered[FilterConstraintHostVolumes], 3)
+}
+
 func TestServiceStack_Select_CSI(t *testing.T) {
 	ci.Parallel(t)