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Add jitter and backoff to prevent thundering herd on auth
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Move cache and resourceWatcher watchers from a 10s retry to a jittered backoff retry up to ~2min. Replace the
reconnectToAuthService interval with a retry to add jitter and backoff there as well for when a node restarts due to
changes introduced in #8102.

Fixes #6889.
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@rosstimothy
rosstimothy committed Dec 7, 2021
1 parent e2a0225 commit e8d70d7
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Showing 7 changed files with 58 additions and 34 deletions.
11 changes: 7 additions & 4 deletions lib/cache/cache.go
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Original file line number Diff line number Diff line change
Expand Up @@ -553,7 +553,7 @@ func (c *Config) CheckAndSetDefaults() error {
c.Clock = clockwork.NewRealClock()
}
if c.RetryPeriod == 0 {
c.RetryPeriod = defaults.HighResPollingPeriod
c.RetryPeriod = time.Minute
}
if c.WatcherInitTimeout == 0 {
c.WatcherInitTimeout = time.Minute
Expand Down Expand Up @@ -660,8 +660,11 @@ func New(config Config) (*Cache, error) {
}

retry, err := utils.NewLinear(utils.LinearConfig{
Step: cs.Config.RetryPeriod / 10,
Max: cs.Config.RetryPeriod,
First: utils.HalfJitter(defaults.HighResPollingPeriod),
Step: cs.Config.RetryPeriod / 2,
Max: cs.Config.RetryPeriod * 2,
Jitter: utils.NewSeventhJitter(),
Clock: cs.Clock,
})
if err != nil {
cs.Close()
Expand Down Expand Up @@ -725,7 +728,7 @@ func (c *Cache) update(ctx context.Context, retry utils.Retry) {
c.Warningf("Re-init the cache on error: %v.", err)
}
// events cache should be closed as well
c.Debugf("Reloading %v.", retry)
c.Debugf("Reloading cache %v.", retry)
select {
case <-retry.After():
retry.Inc()
Expand Down
9 changes: 6 additions & 3 deletions lib/restrictedsession/watcher.go
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Original file line number Diff line number Diff line change
Expand Up @@ -39,8 +39,11 @@ func NewRestrictionsWatcher(cfg RestrictionsWatcherConfig) (*RestrictionsWatcher
return nil, trace.Wrap(err)
}
retry, err := utils.NewLinear(utils.LinearConfig{
Step: cfg.RetryPeriod / 10,
Max: cfg.RetryPeriod,
First: utils.HalfJitter(defaults.HighResPollingPeriod),
Step: cs.Config.RetryPeriod / 2,
Max: cs.Config.RetryPeriod,
Jitter: utils.NewSeventhJitter(),
Clock: cs.Clock,
})
if err != nil {
return nil, trace.Wrap(err)
Expand Down Expand Up @@ -98,7 +101,7 @@ func (cfg *RestrictionsWatcherConfig) CheckAndSetDefaults() error {
return trace.BadParameter("missing parameter RestrictionsC")
}
if cfg.RetryPeriod == 0 {
cfg.RetryPeriod = defaults.HighResPollingPeriod
cfg.RetryPeriod = time.Minute
}
if cfg.ReloadPeriod == 0 {
cfg.ReloadPeriod = defaults.LowResPollingPeriod
Expand Down
8 changes: 5 additions & 3 deletions lib/reversetunnel/rc_manager.go
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Original file line number Diff line number Diff line change
Expand Up @@ -76,6 +76,8 @@ type RemoteClusterTunnelManagerConfig struct {
KubeDialAddr utils.NetAddr
// FIPS indicates if Teleport was started in FIPS mode.
FIPS bool
// Log is the logger
Log logrus.FieldLogger
}

func (c *RemoteClusterTunnelManagerConfig) CheckAndSetDefaults() error {
Expand Down Expand Up @@ -138,7 +140,7 @@ func (w *RemoteClusterTunnelManager) Run(ctx context.Context) {
w.mu.Unlock()

if err := w.Sync(ctx); err != nil {
logrus.Warningf("Failed to sync reverse tunnels: %v.", err)
w.cfg.Log.Warningf("Failed to sync reverse tunnels: %v.", err)
}

ticker := time.NewTicker(defaults.ResyncInterval)
Expand All @@ -147,11 +149,11 @@ func (w *RemoteClusterTunnelManager) Run(ctx context.Context) {
for {
select {
case <-ctx.Done():
logrus.Debugf("Closing.")
w.cfg.Log.Debugf("Closing.")
return
case <-ticker.C:
if err := w.Sync(ctx); err != nil {
logrus.Warningf("Failed to sync reverse tunnels: %v.", err)
w.cfg.Log.Warningf("Failed to sync reverse tunnels: %v.", err)
continue
}
}
Expand Down
40 changes: 26 additions & 14 deletions lib/service/connect.go
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Original file line number Diff line number Diff line change
Expand Up @@ -45,7 +45,17 @@ import (
// reconnectToAuthService continuously attempts to reconnect to the auth
// service until succeeds or process gets shut down
func (process *TeleportProcess) reconnectToAuthService(role types.SystemRole) (*Connector, error) {
retryTime := defaults.HighResPollingPeriod
retry, err := utils.NewLinear(utils.LinearConfig{
First: utils.HalfJitter(defaults.HighResPollingPeriod),
Step: 20 * time.Second,
Max: 3 * time.Minute,
Clock: process.Clock,
Jitter: utils.NewSeventhJitter(),
})
if err != nil {
return nil, trace.Wrap(err)
}

for {
connector, err := process.connectToAuthService(role)
if err == nil {
Expand All @@ -67,8 +77,10 @@ func (process *TeleportProcess) reconnectToAuthService(role types.SystemRole) (*
process.log.Errorf("%v failed to establish connection to cluster: %v.", role, err)

// Wait in between attempts, but return if teleport is shutting down
process.log.Debugf("Retrying connection to auth server in %v", retry)
select {
case <-time.After(retryTime):
case <-retry.After():
retry.Inc()
case <-process.ExitContext().Done():
process.log.Infof("%v stopping connection attempts, teleport is shutting down.", role)
return nil, ErrTeleportExited
Expand Down Expand Up @@ -120,12 +132,12 @@ func (process *TeleportProcess) connect(role types.SystemRole) (conn *Connector,
}, nil
}
process.log.Infof("Connecting to the cluster %v with TLS client certificate.", identity.ClusterName)
client, err := process.newClient(process.Config.AuthServers, identity)
clt, err := process.newClient(process.Config.AuthServers, identity)
if err != nil {
return nil, trace.Wrap(err)
}
return &Connector{
Client: client,
Client: clt,
ClientIdentity: identity,
ServerIdentity: identity,
}, nil
Expand All @@ -140,12 +152,12 @@ func (process *TeleportProcess) connect(role types.SystemRole) (conn *Connector,
ServerIdentity: identity,
}, nil
}
client, err := process.newClient(process.Config.AuthServers, identity)
clt, err := process.newClient(process.Config.AuthServers, identity)
if err != nil {
return nil, trace.Wrap(err)
}
return &Connector{
Client: client,
Client: clt,
ClientIdentity: identity,
ServerIdentity: identity,
}, nil
Expand All @@ -162,12 +174,12 @@ func (process *TeleportProcess) connect(role types.SystemRole) (conn *Connector,
ServerIdentity: identity,
}, nil
}
client, err := process.newClient(process.Config.AuthServers, newIdentity)
clt, err := process.newClient(process.Config.AuthServers, newIdentity)
if err != nil {
return nil, trace.Wrap(err)
}
return &Connector{
Client: client,
Client: clt,
ClientIdentity: newIdentity,
ServerIdentity: identity,
}, nil
Expand All @@ -184,12 +196,12 @@ func (process *TeleportProcess) connect(role types.SystemRole) (conn *Connector,
ServerIdentity: newIdentity,
}, nil
}
client, err := process.newClient(process.Config.AuthServers, newIdentity)
clt, err := process.newClient(process.Config.AuthServers, newIdentity)
if err != nil {
return nil, trace.Wrap(err)
}
return &Connector{
Client: client,
Client: clt,
ClientIdentity: newIdentity,
ServerIdentity: newIdentity,
}, nil
Expand All @@ -204,12 +216,12 @@ func (process *TeleportProcess) connect(role types.SystemRole) (conn *Connector,
ServerIdentity: identity,
}, nil
}
client, err := process.newClient(process.Config.AuthServers, identity)
clt, err := process.newClient(process.Config.AuthServers, identity)
if err != nil {
return nil, trace.Wrap(err)
}
return &Connector{
Client: client,
Client: clt,
ClientIdentity: identity,
ServerIdentity: identity,
}, nil
Expand Down Expand Up @@ -386,14 +398,14 @@ func (process *TeleportProcess) firstTimeConnect(role types.SystemRole) (*Connec
ServerIdentity: identity,
}
} else {
client, err := process.newClient(process.Config.AuthServers, identity)
clt, err := process.newClient(process.Config.AuthServers, identity)
if err != nil {
return nil, trace.Wrap(err)
}
connector = &Connector{
ClientIdentity: identity,
ServerIdentity: identity,
Client: client,
Client: clt,
}
}

Expand Down
10 changes: 6 additions & 4 deletions lib/service/service.go
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Original file line number Diff line number Diff line change
Expand Up @@ -2979,6 +2979,10 @@ func (process *TeleportProcess) initProxyEndpoint(conn *Connector) error {
return trace.Wrap(err)
}

rcWatchLog := logrus.WithFields(logrus.Fields{
trace.Component: teleport.Component(teleport.ComponentReverseTunnelAgent, process.id),
})

// Create and register reverse tunnel AgentPool.
rcWatcher, err := reversetunnel.NewRemoteClusterTunnelManager(reversetunnel.RemoteClusterTunnelManagerConfig{
HostUUID: conn.ServerIdentity.ID.HostUUID,
Expand All @@ -2989,16 +2993,14 @@ func (process *TeleportProcess) initProxyEndpoint(conn *Connector) error {
KubeDialAddr: utils.DialAddrFromListenAddr(kubeDialAddr(cfg.Proxy, clusterNetworkConfig.GetProxyListenerMode())),
ReverseTunnelServer: tsrv,
FIPS: process.Config.FIPS,
Log: rcWatchLog,
})
if err != nil {
return trace.Wrap(err)
}

process.RegisterCriticalFunc("proxy.reversetunnel.watcher", func() error {
log := logrus.WithFields(logrus.Fields{
trace.Component: teleport.Component(teleport.ComponentReverseTunnelAgent, process.id),
})
log.Infof("Starting reverse tunnel agent pool.")
rcWatchLog.Infof("Starting reverse tunnel agent pool.")
done := make(chan struct{})
go func() {
defer close(done)
Expand Down
12 changes: 7 additions & 5 deletions lib/services/watcher.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -75,7 +75,7 @@ func (cfg *ResourceWatcherConfig) CheckAndSetDefaults() error {
cfg.Log = logrus.StandardLogger()
}
if cfg.RetryPeriod == 0 {
cfg.RetryPeriod = defaults.HighResPollingPeriod
cfg.RetryPeriod = time.Minute
}
if cfg.RefetchPeriod == 0 {
cfg.RefetchPeriod = defaults.LowResPollingPeriod
Expand All @@ -94,9 +94,11 @@ func (cfg *ResourceWatcherConfig) CheckAndSetDefaults() error {
// incl. cfg.CheckAndSetDefaults.
func newResourceWatcher(ctx context.Context, collector resourceCollector, cfg ResourceWatcherConfig) (*resourceWatcher, error) {
retry, err := utils.NewLinear(utils.LinearConfig{
Step: cfg.RetryPeriod / 10,
Max: cfg.RetryPeriod,
Clock: cfg.Clock,
First: utils.HalfJitter(defaults.HighResPollingPeriod),
Step: cfg.RetryPeriod / 2,
Max: cfg.RetryPeriod * 2,
Jitter: utils.NewSeventhJitter(),
Clock: cfg.Clock,
})
if err != nil {
return nil, trace.Wrap(err)
Expand Down Expand Up @@ -200,7 +202,7 @@ func (p *resourceWatcher) runWatchLoop() {
return
}
if err != nil {
p.Log.Warningf("Restart watch on error: %v.", err)
p.Log.WithField("retry", p.retry).Warningf("Restart watch on error: %v.", err)
} else {
p.Log.Debug("Triggering scheduled refetch.")
}
Expand Down
2 changes: 1 addition & 1 deletion lib/srv/heartbeat.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -440,7 +440,7 @@ func (h *Heartbeat) announce() error {
if !ok {
return trace.BadParameter("expected services.Server, got %#v", h.current)
}
err := h.Announcer.UpsertKubeService(context.TODO(), kube)
err := h.Announcer.UpsertKubeService(h.cancelCtx, kube)
if err != nil {
h.nextAnnounce = h.Clock.Now().UTC().Add(h.KeepAlivePeriod)
h.setState(HeartbeatStateAnnounceWait)
Expand Down

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