// RecoverDeadMaster recovers a dead master, complete logic inside
func RecoverDeadMaster(topologyRecovery *TopologyRecovery, skipProcesses bool) (promotedSlave *inst.Instance, lostSlaves [](*inst.Instance), err error) {
analysisEntry := &topologyRecovery.AnalysisEntry
failedInstanceKey := &analysisEntry.AnalyzedInstanceKey
inst.AuditOperation("recover-dead-master", failedInstanceKey, "problem found; will recover")
if !skipProcesses {
if err := executeProcesses(config.Config.PreFailoverProcesses, "PreFailoverProcesses", topologyRecovery, true); err != nil {
return nil, lostSlaves, topologyRecovery.AddError(err)
}
}
log.Debugf("topology_recovery: RecoverDeadMaster: will recover %+v", *failedInstanceKey)
var masterRecoveryType MasterRecoveryType = MasterRecoveryPseudoGTID
if analysisEntry.OracleGTIDImmediateTopology || analysisEntry.MariaDBGTIDImmediateTopology {
masterRecoveryType = MasterRecoveryGTID
} else if analysisEntry.BinlogServerImmediateTopology {
masterRecoveryType = MasterRecoveryBinlogServer
}
log.Debugf("topology_recovery: RecoverDeadMaster: masterRecoveryType=%+v", masterRecoveryType)
switch masterRecoveryType {
case MasterRecoveryGTID:
{
lostSlaves, _, promotedSlave, err = inst.RegroupSlavesGTID(failedInstanceKey, true, nil)
}
case MasterRecoveryPseudoGTID:
{
lostSlaves, _, _, promotedSlave, err = inst.RegroupSlavesPseudoGTIDIncludingSubSlavesOfBinlogServers(failedInstanceKey, true, nil, &topologyRecovery.PostponedFunctionsContainer)
}
case MasterRecoveryBinlogServer:
{
promotedSlave, err = recoverDeadMasterInBinlogServerTopology(topologyRecovery)
}
}
topologyRecovery.AddError(err)
if promotedSlave != nil && len(lostSlaves) > 0 && config.Config.DetachLostSlavesAfterMasterFailover {
postponedFunction := func() error {
log.Debugf("topology_recovery: - RecoverDeadMaster: lost %+v slaves during recovery process; detaching them", len(lostSlaves))
for _, slave := range lostSlaves {
slave := slave
inst.DetachSlaveOperation(&slave.Key)
}
return nil
}
topologyRecovery.AddPostponedFunction(postponedFunction)
}
if config.Config.MasterFailoverLostInstancesDowntimeMinutes > 0 {
postponedFunction := func() error {
inst.BeginDowntime(failedInstanceKey, inst.GetMaintenanceOwner(), "RecoverDeadMaster indicates this instance is lost", config.Config.MasterFailoverLostInstancesDowntimeMinutes*60)
for _, slave := range lostSlaves {
slave := slave
inst.BeginDowntime(&slave.Key, inst.GetMaintenanceOwner(), "RecoverDeadMaster indicates this instance is lost", config.Config.MasterFailoverLostInstancesDowntimeMinutes*60)
}
return nil
}
topologyRecovery.AddPostponedFunction(postponedFunction)
}
if promotedSlave == nil {
inst.AuditOperation("recover-dead-master", failedInstanceKey, "Failure: no slave promoted.")
} else {
inst.AuditOperation("recover-dead-master", failedInstanceKey, fmt.Sprintf("promoted slave: %+v", promotedSlave.Key))
}
return promotedSlave, lostSlaves, err
}
// RecoverDeadCoMaster recovers a dead co-master, complete logic inside
func RecoverDeadCoMaster(topologyRecovery *TopologyRecovery, skipProcesses bool) (promotedSlave *inst.Instance, lostSlaves [](*inst.Instance), err error) {
analysisEntry := &topologyRecovery.AnalysisEntry
failedInstanceKey := &analysisEntry.AnalyzedInstanceKey
otherCoMasterKey := &analysisEntry.AnalyzedInstanceMasterKey
otherCoMaster, found, _ := inst.ReadInstance(otherCoMasterKey)
if otherCoMaster == nil || !found {
return nil, lostSlaves, topologyRecovery.AddError(log.Errorf("RecoverDeadCoMaster: could not read info for co-master %+v of %+v", *otherCoMasterKey, *failedInstanceKey))
}
inst.AuditOperation("recover-dead-co-master", failedInstanceKey, "problem found; will recover")
if !skipProcesses {
if err := executeProcesses(config.Config.PreFailoverProcesses, "PreFailoverProcesses", topologyRecovery, true); err != nil {
return nil, lostSlaves, topologyRecovery.AddError(err)
}
}
log.Debugf("topology_recovery: RecoverDeadCoMaster: will recover %+v", *failedInstanceKey)
var coMasterRecoveryType MasterRecoveryType = MasterRecoveryPseudoGTID
if analysisEntry.OracleGTIDImmediateTopology || analysisEntry.MariaDBGTIDImmediateTopology {
coMasterRecoveryType = MasterRecoveryGTID
}
log.Debugf("topology_recovery: RecoverDeadCoMaster: coMasterRecoveryType=%+v", coMasterRecoveryType)
switch coMasterRecoveryType {
case MasterRecoveryGTID:
{
lostSlaves, _, promotedSlave, err = inst.RegroupSlavesGTID(failedInstanceKey, true, nil)
}
case MasterRecoveryPseudoGTID:
{
lostSlaves, _, _, promotedSlave, err = inst.RegroupSlavesPseudoGTIDIncludingSubSlavesOfBinlogServers(failedInstanceKey, true, nil, &topologyRecovery.PostponedFunctionsContainer)
}
}
topologyRecovery.AddError(err)
mustPromoteOtherCoMaster := config.Config.CoMasterRecoveryMustPromoteOtherCoMaster
if !otherCoMaster.ReadOnly {
log.Debugf("topology_recovery: RecoverDeadCoMaster: other co-master %+v is writeable hence has to be promoted", otherCoMaster.Key)
mustPromoteOtherCoMaster = true
}
log.Debugf("topology_recovery: RecoverDeadCoMaster: mustPromoteOtherCoMaster? %+v", mustPromoteOtherCoMaster)
if promotedSlave != nil {
topologyRecovery.ParticipatingInstanceKeys.AddKey(promotedSlave.Key)
if mustPromoteOtherCoMaster {
log.Debugf("topology_recovery: mustPromoteOtherCoMaster. Verifying that %+v is/can be promoted", *otherCoMasterKey)
promotedSlave, err = replacePromotedSlaveWithCandidate(failedInstanceKey, promotedSlave, otherCoMasterKey)
} else {
// We are allowed to promote any server
promotedSlave, err = replacePromotedSlaveWithCandidate(failedInstanceKey, promotedSlave, nil)
if promotedSlave.DataCenter == otherCoMaster.DataCenter &&
promotedSlave.PhysicalEnvironment == otherCoMaster.PhysicalEnvironment && false {
// and _still_ we prefer to promote the co-master! They're in same env & DC so no worries about geo issues!
promotedSlave, err = replacePromotedSlaveWithCandidate(failedInstanceKey, promotedSlave, otherCoMasterKey)
}
}
topologyRecovery.AddError(err)
}
if promotedSlave != nil {
if mustPromoteOtherCoMaster && !promotedSlave.Key.Equals(otherCoMasterKey) {
topologyRecovery.AddError(log.Errorf("RecoverDeadCoMaster: could not manage to promote other-co-master %+v; was only able to promote %+v; CoMasterRecoveryMustPromoteOtherCoMaster is true, therefore failing", *otherCoMasterKey, promotedSlave.Key))
promotedSlave = nil
}
}
if promotedSlave != nil {
topologyRecovery.ParticipatingInstanceKeys.AddKey(promotedSlave.Key)
}
// OK, we may have someone promoted. Either this was the other co-master or another slave.
// Noting down that we DO NOT attempt to set a new co-master topology. We are good with remaining with a single master.
// I tried solving the "let's promote a slave and create a new co-master setup" but this turns so complex due to various factors.
// I see this as risky and not worth the questionable benefit.
// Maybe future me is a smarter person and finds a simple solution. Unlikely. I'm getting dumber.
//
// ...
// Now that we're convinved, take a look at what we can be left with:
// Say we started with M1<->M2<-S1, with M2 failing, and we promoted S1.
// We now have M1->S1 (because S1 is promoted), S1->M2 (because that's what it remembers), M2->M1 (because that's what it remembers)
// !! This is an evil 3-node circle that must be broken.
// config.Config.ApplyMySQLPromotionAfterMasterFailover, if true, will cause it to break, because we would RESET SLAVE on S1
// but we want to make sure the circle is broken no matter what.
// So in the case we promoted not-the-other-co-master, we issue a detach-slave-master-host, which is a reversible operation
if promotedSlave != nil && !promotedSlave.Key.Equals(otherCoMasterKey) {
_, err = inst.DetachSlaveMasterHost(&promotedSlave.Key)
topologyRecovery.AddError(log.Errore(err))
}
if promotedSlave != nil && len(lostSlaves) > 0 && config.Config.DetachLostSlavesAfterMasterFailover {
postponedFunction := func() error {
log.Debugf("topology_recovery: - RecoverDeadCoMaster: lost %+v slaves during recovery process; detaching them", len(lostSlaves))
for _, slave := range lostSlaves {
slave := slave
inst.DetachSlaveOperation(&slave.Key)
}
return nil
}
topologyRecovery.AddPostponedFunction(postponedFunction)
}
if config.Config.MasterFailoverLostInstancesDowntimeMinutes > 0 {
postponedFunction := func() error {
inst.BeginDowntime(failedInstanceKey, inst.GetMaintenanceOwner(), "RecoverDeadCoMaster indicates this instance is lost", config.Config.MasterFailoverLostInstancesDowntimeMinutes*60)
for _, slave := range lostSlaves {
slave := slave
inst.BeginDowntime(&slave.Key, inst.GetMaintenanceOwner(), "RecoverDeadCoMaster indicates this instance is lost", config.Config.MasterFailoverLostInstancesDowntimeMinutes*60)
}
return nil
}
topologyRecovery.AddPostponedFunction(postponedFunction)
}
return promotedSlave, lostSlaves, err
}
// RecoverDeadCoMaster recovers a dead co-master, complete logic inside
func RecoverDeadCoMaster(topologyRecovery *TopologyRecovery, skipProcesses bool) (otherCoMaster *inst.Instance, lostSlaves [](*inst.Instance), err error) {
analysisEntry := &topologyRecovery.AnalysisEntry
failedInstanceKey := &analysisEntry.AnalyzedInstanceKey
otherCoMasterKey := &analysisEntry.AnalyzedInstanceMasterKey
inst.AuditOperation("recover-dead-co-master", failedInstanceKey, "problem found; will recover")
if !skipProcesses {
if err := executeProcesses(config.Config.PreFailoverProcesses, "PreFailoverProcesses", topologyRecovery, true); err != nil {
return nil, lostSlaves, topologyRecovery.AddError(err)
}
}
log.Debugf("topology_recovery: RecoverDeadCoMaster: will recover %+v", *failedInstanceKey)
var coMasterRecoveryType MasterRecoveryType = MasterRecoveryPseudoGTID
if (analysisEntry.OracleGTIDImmediateTopology || analysisEntry.MariaDBGTIDImmediateTopology) && !analysisEntry.PseudoGTIDImmediateTopology {
coMasterRecoveryType = MasterRecoveryGTID
}
log.Debugf("topology_recovery: RecoverDeadCoMaster: coMasterRecoveryType=%+v", coMasterRecoveryType)
var promotedSlave *inst.Instance
switch coMasterRecoveryType {
case MasterRecoveryGTID:
{
lostSlaves, _, promotedSlave, err = inst.RegroupSlavesGTID(failedInstanceKey, true, nil)
}
case MasterRecoveryPseudoGTID:
{
lostSlaves, _, _, promotedSlave, err = inst.RegroupSlavesPseudoGTIDIncludingSubSlavesOfBinlogServers(failedInstanceKey, true, nil, &topologyRecovery.PostponedFunctionsContainer)
}
}
topologyRecovery.AddError(err)
if promotedSlave != nil {
topologyRecovery.ParticipatingInstanceKeys.AddKey(promotedSlave.Key)
promotedSlave, err = replacePromotedSlaveWithCandidate(failedInstanceKey, promotedSlave, otherCoMasterKey)
topologyRecovery.AddError(err)
}
if promotedSlave != nil {
if promotedSlave.Key.Equals(otherCoMasterKey) {
topologyRecovery.ParticipatingInstanceKeys.AddKey(*otherCoMasterKey)
otherCoMaster = promotedSlave
} else {
err = log.Errorf("RecoverDeadCoMaster: could not manage to promote other-co-master %+v; was only able to promote %+v", *otherCoMasterKey, promotedSlave.Key)
promotedSlave = nil
}
}
if promotedSlave != nil && len(lostSlaves) > 0 && config.Config.DetachLostSlavesAfterMasterFailover {
postponedFunction := func() error {
log.Debugf("topology_recovery: - RecoverDeadCoMaster: lost %+v slaves during recovery process; detaching them", len(lostSlaves))
for _, slave := range lostSlaves {
slave := slave
inst.DetachSlaveOperation(&slave.Key)
}
return nil
}
topologyRecovery.AddPostponedFunction(postponedFunction)
}
if config.Config.MasterFailoverLostInstancesDowntimeMinutes > 0 {
postponedFunction := func() error {
inst.BeginDowntime(failedInstanceKey, inst.GetMaintenanceOwner(), "RecoverDeadCoMaster indicates this instance is lost", config.Config.MasterFailoverLostInstancesDowntimeMinutes*60)
for _, slave := range lostSlaves {
slave := slave
inst.BeginDowntime(&slave.Key, inst.GetMaintenanceOwner(), "RecoverDeadCoMaster indicates this instance is lost", config.Config.MasterFailoverLostInstancesDowntimeMinutes*60)
}
return nil
}
topologyRecovery.AddPostponedFunction(postponedFunction)
}
return otherCoMaster, lostSlaves, err
}