handle upgrading old update block syntax

nomad/fsm.go

@@ -247,11 +247,13 @@ func (n *nomadFSM) applyUpsertJob(buf []byte, index uint64) interface{} {
 		panic(fmt.Errorf("failed to decode request: %v", err))
 	}
 
-	// COMPAT: Remove in 0.6
-	// Empty maps and slices should be treated as nil to avoid
-	// un-intended destructive updates in scheduler since we use
-	// reflect.DeepEqual. Starting Nomad 0.4.1, job submission sanatizes
-	// the incoming job.
+	/* Handle upgrade paths:
+	 * - Empty maps and slices should be treated as nil to avoid
+	 *   un-intended destructive updates in scheduler since we use
+	 *   reflect.DeepEqual. Starting Nomad 0.4.1, job submission sanatizes
+	 *   the incoming job.
+	 * - Migrate from old style upgrade stanza that used only a stagger.
+	 */
 	req.Job.Canonicalize()
 
 	if err := n.state.UpsertJob(index, req.Job); err != nil {
@@ -615,11 +617,13 @@ func (n *nomadFSM) Restore(old io.ReadCloser) error {
 				return err
 			}
 
-			// COMPAT: Remove in 0.5
-			// Empty maps and slices should be treated as nil to avoid
-			// un-intended destructive updates in scheduler since we use
-			// reflect.DeepEqual. Starting Nomad 0.4.1, job submission sanatizes
-			// the incoming job.
+			/* Handle upgrade paths:
+			 * - Empty maps and slices should be treated as nil to avoid
+			 *   un-intended destructive updates in scheduler since we use
+			 *   reflect.DeepEqual. Starting Nomad 0.4.1, job submission sanatizes
+			 *   the incoming job.
+			 * - Migrate from old style upgrade stanza that used only a stagger.
+			 */
 			job.Canonicalize()
 
 			if err := restore.JobRestore(job); err != nil {

nomad/structs/structs.go

@@ -1257,6 +1257,45 @@ func (j *Job) Canonicalize() {
 	if j.Periodic != nil {
 		j.Periodic.Canonicalize()
 	}
+
+	// COMPAT: Remove in 0.7.0
+	// Rewrite any job that has an update block with pre 0.6.0 syntax.
+	if j.Update.Stagger > 0 && j.Update.MaxParallel > 0 {
+		// Build an appropriate update block and copy it down to each task group
+		base := DefaultUpdateStrategy.Copy()
+		base.MaxParallel = j.Update.MaxParallel
+		base.MinHealthyTime = j.Update.Stagger
+
+		// Add to each task group, modifying as needed
+		l := len(j.TaskGroups)
+		for _, tg := range j.TaskGroups {
+			// The task group doesn't need upgrading if it has an update block with the new syntax
+			u := tg.Update
+			if u != nil && u.Stagger == 0 && u.MaxParallel > 0 &&
+				u.HealthCheck != "" && u.MinHealthyTime > 0 && u.HealthyDeadline > 0 {
+				continue
+			}
+
+			// The MaxParallel for the job should be 10% of the total count
+			// unless there is just one task group then we can infer the old
+			// max parallel should be the new
+			tgu := base.Copy()
+			if l != 1 {
+				// RoundTo 10%
+				var percent float64 = float64(tg.Count) * 0.1
+				tgu.MaxParallel = int(percent + 0.5)
+			}
+
+			// Safety guards
+			if tgu.MaxParallel == 0 {
+				tgu.MaxParallel = 1
+			} else if tgu.MaxParallel > tg.Count {
+				tgu.MaxParallel = tg.Count
+			}
+
+			tg.Update = tgu
+		}
+	}
 }
 
 // Copy returns a deep copy of the Job. It is expected that callers use recover.
@@ -1626,6 +1665,19 @@ const (
 	UpdateStrategyHealthCheck_Manual = "manual"
 )
 
+var (
+	// DefaultUpdateStrategy provides a baseline that can be used to upgrade
+	// jobs with the old policy
+	DefaultUpdateStrategy = &UpdateStrategy{
+		MaxParallel:     0,
+		HealthCheck:     UpdateStrategyHealthCheck_Checks,
+		MinHealthyTime:  10 * time.Second,
+		HealthyDeadline: 5 * time.Minute,
+		AutoRevert:      false,
+		Canary:          0,
+	}
+)
+
 // UpdateStrategy is used to modify how updates are done
 type UpdateStrategy struct {
 	// COMPAT: Remove in 0.7.0. Stagger is deprecated in 0.6.0.

nomad/structs/structs_test.go

@@ -9,6 +9,7 @@ import (
 
 	"github.com/hashicorp/consul/api"
 	"github.com/hashicorp/go-multierror"
+	"github.com/kr/pretty"
 )
 
 func TestJob_Validate(t *testing.T) {
@@ -134,6 +135,166 @@ func TestJob_Warnings(t *testing.T) {
 	}
 }
 
+func TestJob_Canonicalize_Update(t *testing.T) {
+	cases := []struct {
+		Name     string
+		Job      *Job
+		Expected *Job
+	}{
+		{
+			Name: "One task group",
+			Job: &Job{
+				Update: UpdateStrategy{
+					MaxParallel: 2,
+					Stagger:     10 * time.Second,
+				},
+				TaskGroups: []*TaskGroup{
+					{
+						Name:  "foo",
+						Count: 2,
+					},
+				},
+			},
+			Expected: &Job{
+				Update: UpdateStrategy{
+					MaxParallel: 2,
+					Stagger:     10 * time.Second,
+				},
+				TaskGroups: []*TaskGroup{
+					{
+						Name:          "foo",
+						Count:         2,
+						EphemeralDisk: DefaultEphemeralDisk(),
+						Update: &UpdateStrategy{
+							MaxParallel:     2,
+							HealthCheck:     UpdateStrategyHealthCheck_Checks,
+							MinHealthyTime:  10 * time.Second,
+							HealthyDeadline: 5 * time.Minute,
+							AutoRevert:      false,
+							Canary:          0,
+						},
+					},
+				},
+			},
+		},
+		{
+			Name: "One task group; too high of parallelism",
+			Job: &Job{
+				Update: UpdateStrategy{
+					MaxParallel: 200,
+					Stagger:     10 * time.Second,
+				},
+				TaskGroups: []*TaskGroup{
+					{
+						Name:  "foo",
+						Count: 2,
+					},
+				},
+			},
+			Expected: &Job{
+				Update: UpdateStrategy{
+					MaxParallel: 200,
+					Stagger:     10 * time.Second,
+				},
+				TaskGroups: []*TaskGroup{
+					{
+						Name:          "foo",
+						Count:         2,
+						EphemeralDisk: DefaultEphemeralDisk(),
+						Update: &UpdateStrategy{
+							MaxParallel:     2,
+							HealthCheck:     UpdateStrategyHealthCheck_Checks,
+							MinHealthyTime:  10 * time.Second,
+							HealthyDeadline: 5 * time.Minute,
+							AutoRevert:      false,
+							Canary:          0,
+						},
+					},
+				},
+			},
+		},
+		{
+			Name: "Multiple task group; rounding",
+			Job: &Job{
+				Update: UpdateStrategy{
+					MaxParallel: 2,
+					Stagger:     10 * time.Second,
+				},
+				TaskGroups: []*TaskGroup{
+					{
+						Name:  "foo",
+						Count: 2,
+					},
+					{
+						Name:  "bar",
+						Count: 14,
+					},
+					{
+						Name:  "foo",
+						Count: 26,
+					},
+				},
+			},
+			Expected: &Job{
+				Update: UpdateStrategy{
+					MaxParallel: 2,
+					Stagger:     10 * time.Second,
+				},
+				TaskGroups: []*TaskGroup{
+					{
+						Name:          "foo",
+						Count:         2,
+						EphemeralDisk: DefaultEphemeralDisk(),
+						Update: &UpdateStrategy{
+							MaxParallel:     1,
+							HealthCheck:     UpdateStrategyHealthCheck_Checks,
+							MinHealthyTime:  10 * time.Second,
+							HealthyDeadline: 5 * time.Minute,
+							AutoRevert:      false,
+							Canary:          0,
+						},
+					},
+					{
+						Name:          "bar",
+						Count:         14,
+						EphemeralDisk: DefaultEphemeralDisk(),
+						Update: &UpdateStrategy{
+							MaxParallel:     1,
+							HealthCheck:     UpdateStrategyHealthCheck_Checks,
+							MinHealthyTime:  10 * time.Second,
+							HealthyDeadline: 5 * time.Minute,
+							AutoRevert:      false,
+							Canary:          0,
+						},
+					},
+					{
+						Name:          "foo",
+						Count:         26,
+						EphemeralDisk: DefaultEphemeralDisk(),
+						Update: &UpdateStrategy{
+							MaxParallel:     3,
+							HealthCheck:     UpdateStrategyHealthCheck_Checks,
+							MinHealthyTime:  10 * time.Second,
+							HealthyDeadline: 5 * time.Minute,
+							AutoRevert:      false,
+							Canary:          0,
+						},
+					},
+				},
+			},
+		},
+	}
+
+	for _, c := range cases {
+		t.Run(c.Name, func(t *testing.T) {
+			c.Job.Canonicalize()
+			if !reflect.DeepEqual(c.Job, c.Expected) {
+				t.Fatalf("Got %# v; want %# v", pretty.Formatter(c.Job), pretty.Formatter(c.Expected))
+			}
+		})
+	}
+}
+
 func testJob() *Job {
 	return &Job{
 		Region:      "global",