Merge pull request #6384 from planetscale/ss-resurrect-demote-master-…

…type

vttablet: bring back demote_master_type

go/vt/vttablet/tabletmanager/tm_init.go

@@ -110,6 +110,10 @@ var (
  // The following variables can be changed to speed up tests.
  mysqlPortRetryInterval = 1 * time.Second
  rebuildKeyspaceRetryInterval = 1 * time.Second
+
+ // demoteMasterType is deprecated.
+ // TODO(sougou); remove after release 7.0.
+ demoteMasterType = flag.String("demote_master_type", "REPLICA", "DEPRECATED: the tablet type a demoted master will transition to")
 )
 
 func init() {
@@ -281,6 +285,13 @@ func (tm *TabletManager) Start(tablet *topodatapb.Tablet) error {
  tm.DBConfigs.DBName = topoproto.TabletDbName(tablet)
  tm.History = history.New(historyLength)
  tm.tabletAlias = tablet.Alias
+ demoteType, err := topoproto.ParseTabletType(*demoteMasterType)
+ if err != nil {
+ return err
+ }
+ if demoteType != tablet.Type {
+ log.Warningf("deprecated demote_master_type %v must match init_tablet_type %v", demoteType, tablet.Type)
+ }
  tm.baseTabletType = tablet.Type
  tm._healthy = fmt.Errorf("healthcheck not run yet")
 
@@ -299,7 +310,7 @@ func (tm *TabletManager) Start(tablet *topodatapb.Tablet) error {
  return err
  }
 
- err := tm.QueryServiceControl.InitDBConfig(querypb.Target{
+ err = tm.QueryServiceControl.InitDBConfig(querypb.Target{
  Keyspace: tablet.Keyspace,
  Shard: tablet.Shard,
  TabletType: tablet.Type,