// terminateHealthChecks is called when we enter lame duck mode.
// We will clean up our state, and set query service to lame duck mode.
// We only do something if we are in targetTabletType state, and then
// we just go to spare.
func (agent *ActionAgent) terminateHealthChecks(targetTabletType topodatapb.TabletType) {
agent.actionMutex.Lock()
defer agent.actionMutex.Unlock()
log.Info("agent.terminateHealthChecks is starting")
// read the current tablet record
tablet := agent.Tablet()
if tablet.Type != targetTabletType {
// If we're MASTER, SPARE, WORKER, etc. then the healthcheck shouldn't
// touch it. We also skip gracePeriod in that case.
log.Infof("Tablet in state %v, not changing it", tablet.Type)
return
}
var wg sync.WaitGroup
// Go lameduck for gracePeriod.
// We've already checked above that we're not MASTER.
wg.Add(1)
go func() {
defer wg.Done()
// Enter new lameduck mode for gracePeriod, then shut down queryservice.
// New lameduck mode means keep accepting queries, but advertise unhealthy.
// After we return from this synchronous OnTermSync hook, servenv may decide
// to wait even longer, for the rest of the time specified by its own
// "-lameduck-period" flag. During that extra period, queryservice will be
// in old lameduck mode, meaning stay alive but reject new queries.
agent.enterLameduck("terminating healthchecks")
agent.broadcastHealth()
time.Sleep(*gracePeriod)
agent.disallowQueries(tablet.Type, "terminating healthchecks")
}()
// Change Type to spare and clear HealthMap.
wg.Add(1)
go func() {
defer wg.Done()
// We don't wait until after the lameduck period, because we want to make
// sure this gets done before servenv onTermTimeout.
tablet, err := topotools.ChangeOwnType(agent.batchCtx, agent.TopoServer, agent.initialTablet, topodatapb.TabletType_SPARE, topotools.ClearHealthMap)
if err != nil {
log.Infof("Error updating tablet record: %v", err)
return
}
// Update the serving graph in our cell, only if we're dealing with
// a serving type
if err := agent.updateServingGraph(tablet, targetTabletType); err != nil {
log.Warningf("updateServingGraph failed (will still run post action callbacks, serving graph might be out of date): %v", err)
}
}()
wg.Wait()
}
// terminateHealthChecks is called when we enter lame duck mode.
// We will clean up our state, and shut down query service.
// We only do something if we are in targetTabletType state, and then
// we just go to spare.
func (agent *ActionAgent) terminateHealthChecks(targetTabletType topodatapb.TabletType) {
agent.actionMutex.Lock()
defer agent.actionMutex.Unlock()
log.Info("agent.terminateHealthChecks is starting")
// read the current tablet record
tablet := agent.Tablet()
if tablet.Type != targetTabletType {
log.Infof("Tablet in state %v, not changing it", tablet.Type)
return
}
// Change the Type to spare, update the health. Note we pass in a map
// that's not nil, meaning we will clear it.
if err := topotools.ChangeOwnType(agent.batchCtx, agent.TopoServer, agent.initialTablet, topodatapb.TabletType_SPARE, make(map[string]string)); err != nil {
log.Infof("Error updating tablet record: %v", err)
return
}
// The change above succeeded, so update our local copy.
tablet, err := agent.updateTabletFromTopo(agent.batchCtx)
if err != nil {
log.Infof("Error re-reading tablet record: %v", err)
return
}
// Update the serving graph in our cell, only if we're dealing with
// a serving type
if err := agent.updateServingGraph(tablet, targetTabletType); err != nil {
log.Warningf("updateServingGraph failed (will still run post action callbacks, serving graph might be out of date): %v", err)
}
// We've already rebuilt the shard, which is the only reason we registered
// ourself as OnTermSync (synchronous). The rest can be done asynchronously.
go func() {
// Run the post action callbacks (let them shutdown the query service)
if err := agent.refreshTablet(agent.batchCtx, "terminatehealthcheck"); err != nil {
log.Warningf("refreshTablet failed: %v", err)
}
}()
}
// runHealthCheck takes the action mutex, runs the health check,
// and if we need to change our state, do it.
// If we are the master, we don't change our type, healthy or not.
// If we are not the master, we change to spare if not healthy,
// or to the passed in targetTabletType if healthy.
//
// Note we only update the topo record if we need to, that is if our type or
// health details changed.
//
// This will not change the BinlogPlayerMap, but if it is not empty,
// we will think we should not be running the query service.
//
// This will not change the TabletControl record, but will use it
// to see if we should be running the query service.
func (agent *ActionAgent) runHealthCheck(targetTabletType topodatapb.TabletType) {
agent.actionMutex.Lock()
defer agent.actionMutex.Unlock()
// read the current tablet record and tablet control
agent.mutex.Lock()
tablet := agent._tablet
tabletControl := agent._tabletControl
agent.mutex.Unlock()
// figure out if we should be running the query service
shouldBeServing := false
if topo.IsRunningQueryService(targetTabletType) && !agent.BinlogPlayerMap.isRunningFilteredReplication() {
shouldBeServing = true
if tabletControl != nil {
if tabletControl.DisableQueryService {
shouldBeServing = false
}
}
}
// run the health check
isSlaveType := true
if tablet.Type == topodatapb.TabletType_MASTER {
isSlaveType = false
}
replicationDelay, err := agent.HealthReporter.Report(isSlaveType, shouldBeServing)
health := make(map[string]string)
if err == nil {
if replicationDelay > *unhealthyThreshold {
err = fmt.Errorf("reported replication lag: %v higher than unhealthy threshold: %v", replicationDelay.Seconds(), unhealthyThreshold.Seconds())
} else if replicationDelay > *degradedThreshold {
health[topo.ReplicationLag] = topo.ReplicationLagHigh
}
}
agent.lastHealthMapCount.Set(int64(len(health)))
// Figure out if we should be running QueryService, see if we are,
// and reconcile.
if err != nil {
if tablet.Type != topodatapb.TabletType_WORKER {
// We are not healthy and must shut down QueryService.
// At the moment, the only exception to this are "worker" tablets which
// still must serve queries e.g. as source tablet during a "SplitClone".
shouldBeServing = false
}
}
isServing := agent.QueryServiceControl.IsServing()
if shouldBeServing {
if !isServing {
// send the type we want to be, not the type we are
desiredType := tablet.Type
if desiredType == topodatapb.TabletType_SPARE {
desiredType = targetTabletType
}
// we remember this new possible error
err = agent.allowQueries(desiredType)
}
} else {
if isServing {
// We are not healthy or should not be running the
// query service, shut it down.
// Note this is possibly sending 'spare' as
// the tablet type, we will clean it up later.
agent.disallowQueries(tablet.Tablet.Type,
fmt.Sprintf("health-check failure(%v)", err),
)
}
}
// save the health record
record := &HealthRecord{
Error: err,
ReplicationDelay: replicationDelay,
Time: time.Now(),
}
agent.History.Add(record)
// try to figure out the mysql port if we don't have it yet
if _, ok := tablet.PortMap["mysql"]; !ok {
// we don't know the port, try to get it from mysqld
mysqlPort, err := agent.MysqlDaemon.GetMysqlPort()
if err != nil {
// Don't log if we're already in a waiting-for-mysql state.
agent.mutex.Lock()
if !agent._waitingForMysql {
log.Warningf("Can't get mysql port, won't populate Tablet record in topology (will retry silently at healthcheck interval %v): %v", *healthCheckInterval, err)
agent._waitingForMysql = true
}
agent.mutex.Unlock()
} else {
log.Infof("Updating tablet mysql port to %v", mysqlPort)
if err := agent.TopoServer.UpdateTabletFields(agent.batchCtx, tablet.Alias, func(tablet *topodatapb.Tablet) error {
if err := topotools.CheckOwnership(agent.initialTablet, tablet); err != nil {
return err
}
tablet.PortMap["mysql"] = mysqlPort
return nil
}); err != nil {
log.Infof("Error updating mysql port in tablet record, will try again: %v", err)
return
}
// save the port so we don't update it again next time
// we do the health check.
agent.mutex.Lock()
agent._tablet.PortMap["mysql"] = mysqlPort
agent._waitingForMysql = false
agent.mutex.Unlock()
}
}
// remember our health status
agent.mutex.Lock()
agent._healthy = err
agent._healthyTime = time.Now()
agent._replicationDelay = replicationDelay
agent.mutex.Unlock()
// send it to our observers
agent.broadcastHealth()
// Update our topo.Server state, start with no change
newTabletType := tablet.Type
if err != nil {
// The tablet is not healthy, let's see what we need to do
if tablet.Type != targetTabletType {
if tablet.Type != topodatapb.TabletType_SPARE {
// we only log if we're not in spare,
// as the spare state is normal for a
// failed health check.
log.Infof("Tablet not healthy and in state %v, not changing it: %v", tablet.Type, err)
}
return
}
// Note that if the query service is running, we may
// need to stop it. The post-action callback will do
// it, and it will be done after we change our state,
// so it's the right order, let it do it.
log.Infof("Tablet not healthy, converting it from %v to spare: %v", targetTabletType, err)
newTabletType = topodatapb.TabletType_SPARE
} else {
// We are healthy, maybe with health, see if we need
// to update the record. We only change from spare to
// our target type.
if tablet.Type == topodatapb.TabletType_SPARE {
newTabletType = targetTabletType
}
if tablet.Type == newTabletType && topo.IsHealthEqual(health, tablet.HealthMap) {
// no change in health, not logging anything,
// and we're done
return
}
// we need to update our state
log.Infof("Updating tablet record as healthy type %v -> %v with health details %v -> %v", tablet.Type, newTabletType, tablet.HealthMap, health)
}
// Change the Type, update the health. Note we pass in a map
// that's not nil, meaning if it's empty, we will clear it.
if err := topotools.ChangeOwnType(agent.batchCtx, agent.TopoServer, agent.initialTablet, newTabletType, health); err != nil {
log.Infof("Error updating tablet record: %v", err)
return
}
tablet.HealthMap = health
tablet.Type = newTabletType
// Rebuild the serving graph in our cell, only if we're dealing with
// a serving type
if err := agent.updateServingGraph(tablet, targetTabletType); err != nil {
log.Warningf("updateServingGraph failed (will still run post action callbacks, serving graph might be out of date): %v", err)
}
// run the post action callbacks, not much we can do with returned error
if err := agent.refreshTablet(agent.batchCtx, "healthcheck"); err != nil {
log.Warningf("refreshTablet failed: %v", err)
}
}