diff --git a/nomad/drainer/drainer.go b/nomad/drainer/drainer.go
index c5d4d6a7cad..2e4e8528ffc 100644
--- a/nomad/drainer/drainer.go
+++ b/nomad/drainer/drainer.go
@@ -392,25 +392,25 @@ func (n *NodeDrainer) batchDrainAllocs(allocs []*structs.Allocation) (uint64, er
 // affected jobs.
 func (n *NodeDrainer) drainAllocs(future *structs.BatchFuture, allocs []*structs.Allocation) {
 	// Compute the effected jobs and make the transition map
-	jobs := make(map[string]*structs.Allocation, 4)
+	jobs := make(map[structs.NamespacedID]*structs.Allocation, 4)
 	transitions := make(map[string]*structs.DesiredTransition, len(allocs))
 	for _, alloc := range allocs {
 		transitions[alloc.ID] = &structs.DesiredTransition{
 			Migrate: helper.BoolToPtr(true),
 		}
-		jobs[alloc.JobID] = alloc
+		jobs[alloc.JobNamespacedID()] = alloc
 	}
 
 	evals := make([]*structs.Evaluation, 0, len(jobs))
 	now := time.Now().UTC().UnixNano()
-	for job, alloc := range jobs {
+	for _, alloc := range jobs {
 		evals = append(evals, &structs.Evaluation{
 			ID:          uuid.Generate(),
 			Namespace:   alloc.Namespace,
 			Priority:    alloc.Job.Priority,
 			Type:        alloc.Job.Type,
 			TriggeredBy: structs.EvalTriggerNodeDrain,
-			JobID:       job,
+			JobID:       alloc.JobID,
 			Status:      structs.EvalStatusPending,
 			CreateTime:  now,
 			ModifyTime:  now,
diff --git a/nomad/drainer_int_test.go b/nomad/drainer_int_test.go
index 7cfea74abf6..739e2e14df9 100644
--- a/nomad/drainer_int_test.go
+++ b/nomad/drainer_int_test.go
@@ -880,6 +880,135 @@ func TestDrainer_AllTypes_Deadline_GarbageCollectedNode(t *testing.T) {
 	require.Contains(node.Events[2].Details, drainer.NodeDrainEventDetailDeadlined)
 }
 
+// TestDrainer_MultipleNSes_ServiceOnly asserts that all jobs on an alloc, even
+// when they belong to different namespaces and share the same ID
+func TestDrainer_MultipleNSes_ServiceOnly(t *testing.T) {
+	t.Parallel()
+	require := require.New(t)
+
+	s1, cleanupS1 := TestServer(t, nil)
+	defer cleanupS1()
+	codec := rpcClient(t, s1)
+	testutil.WaitForLeader(t, s1.RPC)
+
+	// Create two nodes
+	n1, n2 := mock.Node(), mock.Node()
+	nodeReg := &structs.NodeRegisterRequest{
+		Node:         n1,
+		WriteRequest: structs.WriteRequest{Region: "global"},
+	}
+	var nodeResp structs.NodeUpdateResponse
+	require.NoError(msgpackrpc.CallWithCodec(codec, "Node.Register", nodeReg, &nodeResp))
+
+	ns1, ns2 := mock.Namespace(), mock.Namespace()
+	nses := []*structs.Namespace{ns1, ns2}
+	nsReg := &structs.NamespaceUpsertRequest{
+		Namespaces:   nses,
+		WriteRequest: structs.WriteRequest{Region: "global"},
+	}
+	var nsResp structs.GenericResponse
+	require.NoError(msgpackrpc.CallWithCodec(codec, "Namespace.UpsertNamespaces", nsReg, &nsResp))
+
+	for _, ns := range nses {
+		// Create a job that runs on just one
+		job := mock.Job()
+		job.ID = "example"
+		job.Name = "example"
+		job.Namespace = ns.Name
+		job.TaskGroups[0].Count = 1
+		req := &structs.JobRegisterRequest{
+			Job: job,
+			WriteRequest: structs.WriteRequest{
+				Region:    "global",
+				Namespace: job.Namespace,
+			},
+		}
+
+		// Fetch the response
+		var resp structs.JobRegisterResponse
+		require.Nil(msgpackrpc.CallWithCodec(codec, "Job.Register", req, &resp))
+		require.NotZero(resp.Index)
+	}
+
+	// Wait for the two allocations to be placed
+	state := s1.State()
+	testutil.WaitForResult(func() (bool, error) {
+		iter, err := state.Allocs(nil)
+		if err != nil {
+			return false, err
+		}
+
+		count := 0
+		for iter.Next() != nil {
+			count++
+		}
+		if count != 2 {
+			return false, fmt.Errorf("expected %d allocs, found %d", 2, count)
+		}
+		return true, nil
+	}, func(err error) {
+		require.NoError(err)
+	})
+
+	// Create the second node
+	nodeReg = &structs.NodeRegisterRequest{
+		Node:         n2,
+		WriteRequest: structs.WriteRequest{Region: "global"},
+	}
+	require.Nil(msgpackrpc.CallWithCodec(codec, "Node.Register", nodeReg, &nodeResp))
+
+	// Drain the first node
+	drainReq := &structs.NodeUpdateDrainRequest{
+		NodeID: n1.ID,
+		DrainStrategy: &structs.DrainStrategy{
+			DrainSpec: structs.DrainSpec{
+				Deadline: 10 * time.Minute,
+			},
+		},
+		WriteRequest: structs.WriteRequest{Region: "global"},
+	}
+	var drainResp structs.NodeDrainUpdateResponse
+	require.Nil(msgpackrpc.CallWithCodec(codec, "Node.UpdateDrain", drainReq, &drainResp))
+
+	// Wait for the allocs to be replaced
+	errCh := make(chan error, 2)
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	go allocPromoter(errCh, ctx, state, codec, n1.ID, s1.logger)
+	go allocPromoter(errCh, ctx, state, codec, n2.ID, s1.logger)
+
+	testutil.WaitForResult(func() (bool, error) {
+		allocs, err := state.AllocsByNode(nil, n2.ID)
+		if err != nil {
+			return false, err
+		}
+		return len(allocs) == 2, fmt.Errorf("got %d allocs", len(allocs))
+	}, func(err error) {
+		require.NoError(err)
+	})
+
+	// Check that the node drain is removed
+	testutil.WaitForResult(func() (bool, error) {
+		if err := checkAllocPromoter(errCh); err != nil {
+			return false, err
+		}
+		node, err := state.NodeByID(nil, n1.ID)
+		if err != nil {
+			return false, err
+		}
+		return node.DrainStrategy == nil, fmt.Errorf("has drain strategy still set")
+	}, func(err error) {
+		require.NoError(err)
+	})
+
+	// Check we got the right events
+	node, err := state.NodeByID(nil, n1.ID)
+	require.NoError(err)
+	// sometimes test gets a duplicate node drain complete event
+	require.GreaterOrEqualf(len(node.Events), 3, "unexpected number of events: %v", node.Events)
+	require.Equal(drainer.NodeDrainEventComplete, node.Events[2].Message)
+}
+
 // Test that transitions to force drain work.
 func TestDrainer_Batch_TransitionToForce(t *testing.T) {
 	t.Parallel()
diff --git a/nomad/structs/structs.go b/nomad/structs/structs.go
index 65b874ad6d4..53c249f8db2 100644
--- a/nomad/structs/structs.go
+++ b/nomad/structs/structs.go
@@ -9136,6 +9136,10 @@ func (a *Allocation) ConsulNamespace() string {
 	return a.Job.LookupTaskGroup(a.TaskGroup).Consul.GetNamespace()
 }
 
+func (a *Allocation) JobNamespacedID() NamespacedID {
+	return NewNamespacedID(a.JobID, a.Namespace)
+}
+
 // Index returns the index of the allocation. If the allocation is from a task
 // group with count greater than 1, there will be multiple allocations for it.
 func (a *Allocation) Index() uint {