func (wr *Wrangler) finishReparent(si *topo.ShardInfo, masterElect *topo.TabletInfo, majorityRestart, leaveMasterReadOnly bool) error {
// If the majority of slaves restarted, move ahead.
if majorityRestart {
if leaveMasterReadOnly {
log.Warningf("leaving master-elect read-only, change with: vtctl SetReadWrite %v", masterElect.Alias)
} else {
log.Infof("marking master-elect read-write %v", masterElect.Alias)
actionPath, err := wr.ai.SetReadWrite(masterElect.Alias)
if err == nil {
err = wr.ai.WaitForCompletion(actionPath, wr.actionTimeout())
}
if err != nil {
log.Warningf("master master-elect read-write failed, leaving master-elect read-only, change with: vtctl SetReadWrite %v", masterElect.Alias)
}
}
} else {
log.Warningf("minority reparent, manual fixes are needed, leaving master-elect read-only, change with: vtctl SetReadWrite %v", masterElect.Alias)
}
// save the new master in the shard info
si.MasterAlias = masterElect.Alias
if err := wr.ts.UpdateShard(si); err != nil {
log.Errorf("Failed to save new master into shard: %v", err)
return err
}
// We rebuild all the cells, as we may have taken tablets in and
// out of the graph.
log.Infof("rebuilding shard serving graph data")
return topotools.RebuildShard(wr.ts, masterElect.Keyspace, masterElect.Shard, topotools.RebuildShardOptions{IgnorePartialResult: false}, wr.lockTimeout, interrupted)
}
func (wr *Wrangler) finishReparent(si *topo.ShardInfo, masterElect *topo.TabletInfo, majorityRestart, leaveMasterReadOnly bool) error {
// If the majority of slaves restarted, move ahead.
if majorityRestart {
if leaveMasterReadOnly {
wr.logger.Warningf("leaving master-elect read-only, change with: vtctl SetReadWrite %v", masterElect.Alias)
} else {
wr.logger.Infof("marking master-elect read-write %v", masterElect.Alias)
if err := wr.tmc.SetReadWrite(masterElect, wr.ActionTimeout()); err != nil {
wr.logger.Warningf("master master-elect read-write failed, leaving master-elect read-only, change with: vtctl SetReadWrite %v", masterElect.Alias)
}
}
} else {
wr.logger.Warningf("minority reparent, manual fixes are needed, leaving master-elect read-only, change with: vtctl SetReadWrite %v", masterElect.Alias)
}
// save the new master in the shard info
si.MasterAlias = masterElect.Alias
if err := topo.UpdateShard(wr.ts, si); err != nil {
wr.logger.Errorf("Failed to save new master into shard: %v", err)
return err
}
// We rebuild all the cells, as we may have taken tablets in and
// out of the graph.
wr.logger.Infof("rebuilding shard serving graph data")
_, err := topotools.RebuildShard(wr.logger, wr.ts, masterElect.Keyspace, masterElect.Shard, nil, wr.lockTimeout, interrupted)
return err
}
// updateShardCellsAndMaster will update the 'Cells' and possibly
// MasterAlias records for the shard, if needed.
func (wr *Wrangler) updateShardCellsAndMaster(ctx context.Context, si *topo.ShardInfo, tabletAlias topo.TabletAlias, tabletType topo.TabletType, force bool) error {
// See if we need to update the Shard:
// - add the tablet's cell to the shard's Cells if needed
// - change the master if needed
shardUpdateRequired := false
if !si.HasCell(tabletAlias.Cell) {
shardUpdateRequired = true
}
if tabletType == topo.TYPE_MASTER && si.MasterAlias != tabletAlias {
shardUpdateRequired = true
}
if !shardUpdateRequired {
return nil
}
actionNode := actionnode.UpdateShard()
keyspace := si.Keyspace()
shard := si.ShardName()
lockPath, err := wr.lockShard(ctx, keyspace, shard, actionNode)
if err != nil {
return err
}
// re-read the shard with the lock
si, err = wr.ts.GetShard(ctx, keyspace, shard)
if err != nil {
return wr.unlockShard(ctx, keyspace, shard, actionNode, lockPath, err)
}
// update it
wasUpdated := false
if !si.HasCell(tabletAlias.Cell) {
si.Cells = append(si.Cells, tabletAlias.Cell)
wasUpdated = true
}
if tabletType == topo.TYPE_MASTER && si.MasterAlias != tabletAlias {
if !si.MasterAlias.IsZero() && !force {
return wr.unlockShard(ctx, keyspace, shard, actionNode, lockPath, fmt.Errorf("creating this tablet would override old master %v in shard %v/%v", si.MasterAlias, keyspace, shard))
}
si.MasterAlias = tabletAlias
wasUpdated = true
}
if wasUpdated {
// write it back
if err := topo.UpdateShard(ctx, wr.ts, si); err != nil {
return wr.unlockShard(ctx, keyspace, shard, actionNode, lockPath, err)
}
}
// and unlock
return wr.unlockShard(ctx, keyspace, shard, actionNode, lockPath, err)
}
// finalizeTabletExternallyReparented performs slow, synchronized reconciliation
// tasks that ensure topology is self-consistent, and then marks the reparent as
// finished by updating the global shard record.
func (agent *ActionAgent) finalizeTabletExternallyReparented(ctx context.Context, si *topo.ShardInfo, ev *events.Reparent) (err error) {
var wg sync.WaitGroup
var errs concurrency.AllErrorRecorder
oldMasterAlias := si.MasterAlias
// Update the tablet records concurrently.
event.DispatchUpdate(ev, "updating old and new master tablet records")
log.Infof("finalizeTabletExternallyReparented: updating tablet records")
wg.Add(1)
go func() {
defer wg.Done()
// Update our own record to master.
_, err := agent.TopoServer.UpdateTabletFields(ctx, agent.TabletAlias,
func(tablet *topodatapb.Tablet) error {
tablet.Type = topodatapb.TabletType_MASTER
return nil
})
if err != nil {
errs.RecordError(err)
}
}()
if !topoproto.TabletAliasIsZero(oldMasterAlias) {
wg.Add(1)
go func() {
// Forcibly demote the old master in topology, since we can't rely on the
// old master to be up to change its own record.
oldMasterTablet, err := agent.TopoServer.UpdateTabletFields(ctx, oldMasterAlias,
func(tablet *topodatapb.Tablet) error {
tablet.Type = topodatapb.TabletType_REPLICA
return nil
})
if err != nil {
errs.RecordError(err)
wg.Done()
return
}
// We now know more about the old master, so add it to event data.
ev.OldMaster = *oldMasterTablet
wg.Done()
// Tell the old master to re-read its tablet record and change its state.
// We don't need to wait for it.
tmc := tmclient.NewTabletManagerClient()
tmc.RefreshState(ctx, oldMasterTablet)
}()
}
tablet := agent.Tablet()
// Wait for the tablet records to be updated. At that point, any rebuild will
// see the new master, so we're ready to mark the reparent as done in the
// global shard record.
wg.Wait()
if errs.HasErrors() {
return errs.Error()
}
// Update the master field in the global shard record. We don't use a lock
// here anymore. The lock was only to ensure that the global shard record
// didn't get modified between the time when we read it and the time when we
// write it back. Now we use an update loop pattern to do that instead.
event.DispatchUpdate(ev, "updating global shard record")
log.Infof("finalizeTabletExternallyReparented: updating global shard record if needed")
_, err = agent.TopoServer.UpdateShardFields(ctx, tablet.Keyspace, tablet.Shard, func(si *topo.ShardInfo) error {
if topoproto.TabletAliasEqual(si.MasterAlias, tablet.Alias) {
return topo.ErrNoUpdateNeeded
}
si.MasterAlias = tablet.Alias
return nil
})
if err != nil {
return err
}
event.DispatchUpdate(ev, "finished")
return nil
}