func (wr *Wrangler) restartSlavesExternal(slaveTabletMap, masterTabletMap map[topo.TabletAlias]*topo.TabletInfo, masterElectTablet *topo.TabletInfo, scrapStragglers, continueOnUnexpectedMaster bool, acceptSuccessPercents int) error {
recorder := concurrency.AllErrorRecorder{}
wg := sync.WaitGroup{}
swrd := actionnode.SlaveWasRestartedArgs{
Parent: masterElectTablet.Alias,
ExpectedMasterAddr: masterElectTablet.GetMysqlAddr(),
ExpectedMasterIpAddr: masterElectTablet.GetMysqlIpAddr(),
ScrapStragglers: scrapStragglers,
// Disabled for now
// ContinueOnUnexpectedMaster: continueOnUnexpectedMaster,
}
// The following two blocks of actions are very likely to time
// out for some tablets (one random guy is dead, the old
// master is dead, ...). We execute them all in parallel until
// we get to wr.actionTimeout(). After this, no other action
// with a timeout is executed, so even if we got to the
// timeout, we're still good.
log.Infof("Making sure all tablets have the right master:")
// do all the slaves
for _, ti := range slaveTabletMap {
wg.Add(1)
go func(ti *topo.TabletInfo) {
recorder.RecordError(wr.slaveWasRestarted(ti, &swrd))
wg.Done()
}(ti)
}
// and do the old master and any straggler, if possible, but
// do not record errors for these
for _, ti := range masterTabletMap {
wg.Add(1)
go func(ti *topo.TabletInfo) {
err := wr.slaveWasRestarted(ti, &swrd)
if err != nil {
// the old master can be annoying if left
// around in the replication graph, so if we
// can't restart it, we just scrap it.
// We don't rebuild the Shard just yet though.
log.Warningf("Old master %v is not restarting, scrapping it: %v", ti.Alias, err)
if _, err := wr.Scrap(ti.Alias, true /*force*/, true /*skipRebuild*/); err != nil {
log.Warningf("Failed to scrap old master %v: %v", ti.Alias, err)
}
}
wg.Done()
}(ti)
}
wg.Wait()
if !recorder.HasErrors() {
return nil
}
// report errors only above a threshold
failurePercent := 100 * len(recorder.Errors) / (len(slaveTabletMap) + 1)
if failurePercent < 100-acceptSuccessPercents {
log.Warningf("Encountered %v%% failure, we keep going. Errors: %v", failurePercent, recorder.Error())
return nil
}
return recorder.Error()
}