From c998b67b8e9ec0ef2dfe9d20c5e06339fd93c82a Mon Sep 17 00:00:00 2001
From: Preetha Appan <preetha@hashicorp.com>
Date: Tue, 29 Jan 2019 12:47:42 -0600
Subject: [PATCH] Make sure that all servers are 0.9 before applying scheduler
 config entry

---
 nomad/leader.go | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/nomad/leader.go b/nomad/leader.go
index 55bd2857e..b8de496e8 100644
--- a/nomad/leader.go
+++ b/nomad/leader.go
@@ -42,6 +42,8 @@ const (
 
 var minAutopilotVersion = version.Must(version.NewVersion("0.8.0"))
 
+var minSchedulerconfigVersion = version.Must(version.NewVersion("0.9.0"))
+
 // Default configuration for scheduler with preemption enabled for system jobs
 var defaultSchedulerConfig = &structs.SchedulerConfiguration{
 	PreemptionConfig: structs.PreemptionConfig{
@@ -1267,6 +1269,10 @@ func (s *Server) getOrCreateSchedulerConfig() *structs.SchedulerConfiguration {
 	if config != nil {
 		return config
 	}
+	if !ServersMeetMinimumVersion(s.Members(), minSchedulerconfigVersion) {
+		s.logger.Named("core").Warn("can't initialize scheduler config until all servers are above minimum version", "min_version", minSchedulerconfigVersion)
+		return nil
+	}
 
 	req := structs.SchedulerSetConfigRequest{Config: *defaultSchedulerConfig}
 	if _, _, err = s.raftApply(structs.SchedulerConfigRequestType, req); err != nil {