Allow job Version to start at non-zero value

Stop coercing version of new job to 0 in the state_store, so that we can add
regions to a multi-region deployment. Send new version, rather than existing
version, to MRD to accomodate version-choosing logic changes in ENT.

Co-authored-by: Chris Baker <1675087+cgbaker@users.noreply.github.com>

nomad/job_endpoint.go

@@ -327,11 +327,11 @@ func (j *Job) Register(args *structs.JobRegisterRequest, reply *structs.JobRegis
 
 	// Submit a multiregion job to other regions (enterprise only).
 	// The job will have its region interpolated.
-	var existingVersion uint64
+	var newVersion uint64
 	if existingJob != nil {
-		existingVersion = existingJob.Version
+		newVersion = existingJob.Version + 1
 	}
-	isRunner, err := j.multiregionRegister(args, reply, existingVersion)
+	isRunner, err := j.multiregionRegister(args, reply, newVersion)
 	if err != nil {
 		return err
 	}

nomad/job_endpoint_oss.go

@@ -16,7 +16,7 @@ func (j *Job) enforceSubmitJob(override bool, job *structs.Job) (error, error) {
 }
 
 // multiregionRegister is used to send a job across multiple regions
-func (j *Job) multiregionRegister(args *structs.JobRegisterRequest, reply *structs.JobRegisterResponse, existingVersion uint64) (bool, error) {
+func (j *Job) multiregionRegister(args *structs.JobRegisterRequest, reply *structs.JobRegisterResponse, newVersion uint64) (bool, error) {
 	return false, nil
 }
 

nomad/state/state_store.go

@@ -1434,7 +1434,6 @@ func (s *StateStore) upsertJobImpl(index uint64, job *structs.Job, keepVersion b
 		job.CreateIndex = index
 		job.ModifyIndex = index
 		job.JobModifyIndex = index
-		job.Version = 0
 
 		if err := s.setJobStatus(index, txn, job, false, ""); err != nil {
 			return fmt.Errorf("setting job status for %q failed: %v", job.ID, err)