start all but first region deployment in paused state

nomad/structs/structs.go

@@ -3772,7 +3772,7 @@ func (j *Job) Validate() error {
 	if j.Priority < JobMinPriority || j.Priority > JobMaxPriority {
 		mErr.Errors = append(mErr.Errors, fmt.Errorf("Job priority must be between [%d, %d]", JobMinPriority, JobMaxPriority))
 	}
-	if len(j.Datacenters) == 0 {
+	if len(j.Datacenters) == 0 && !j.IsMultiregion() {
 		mErr.Errors = append(mErr.Errors, errors.New("Missing job datacenters"))
 	} else {
 		for _, v := range j.Datacenters {

scheduler/reconcile.go

@@ -546,6 +546,11 @@ func (a *allocReconciler) computeGroup(group string, all allocSet) bool {
 		// A previous group may have made the deployment already
 		if a.deployment == nil {
 			a.deployment = structs.NewDeployment(a.job)
+			// only the first region of a multiregion job starts in the
+			// running state
+			if a.job.IsMultiregion() && a.job.Region != a.job.Multiregion.Regions[0].Name {
+				a.deployment.Status = structs.DeploymentStatusPaused
+			}
 			a.result.deployment = a.deployment
 		}