Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Deadlock detector hack for Kafka driver instability #1087

Merged
merged 11 commits into from
Oct 9, 2018
Merged
58 changes: 42 additions & 16 deletions cmd/ingester/app/consumer/consumer.go
Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@ package consumer

import (
"sync"
"time"

"github.com/Shopify/sarama"
sc "github.com/bsm/sarama-cluster"
Expand All @@ -42,6 +43,9 @@ type Consumer struct {
internalConsumer consumer.Consumer
processorFactory ProcessorFactory

deadlockDetectorFactory deadlockDetectorFactory
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I think it would be cleaner and easier to understand if you had a top-level deadlockDetector, which can create partitionDeadlockDetector as needed (implementation-wide the former may contain the latter for pId=-1). So factory is only used once to create the top-level detector, and the factory does not need to be stored in the Consumer.

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Doesn't this mean that the top level deadlockDetector also has the responsibilities of the Factor? (That being said, I think it might be cleaner design)

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

it does, in a way, but there's nothing wrong with that, especially considering that it happens at runtime and many times, whereas the top-level factory will be used only once on startup and not needed afterwards.

Separating top-level from individual detectors will also allow clean separation in some implementation details, e.g. where some features are not used.

And best of all, you'll be able to move a lot of methods into detectors, away from Consumer.

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

👍

allPartitionDeadlockDetector *deadlockDetector
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

nit: allPartitions...

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

👍


partitionIDToState map[int32]*consumerState
}

Expand All @@ -52,12 +56,15 @@ type consumerState struct {

// New is a constructor for a Consumer
func New(params Params) (*Consumer, error) {
deadlockDetectorFactory := newDeadlockDetectorFactory(params.Factory, params.Logger, time.Minute)
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

separate issue: s/params.Factory/params.MetricsFactory/

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I'll address this separately - it'll only add noise to this PR

return &Consumer{
metricsFactory: params.Factory,
logger: params.Logger,
internalConsumer: params.InternalConsumer,
processorFactory: params.ProcessorFactory,
partitionIDToState: make(map[int32]*consumerState),
metricsFactory: params.Factory,
logger: params.Logger,
internalConsumer: params.InternalConsumer,
processorFactory: params.ProcessorFactory,
deadlockDetectorFactory: deadlockDetectorFactory,
allPartitionDeadlockDetector: deadlockDetectorFactory.startMonitoring(),
partitionIDToState: make(map[int32]*consumerState),
}, nil
}

Expand All @@ -73,6 +80,7 @@ func (c *Consumer) Start() {
// to the cleanup process not completing
p.wg.Wait()
}
c.newPartitionMetrics(pc.Partition()).startCounter.Inc(1)
c.partitionIDToState[pc.Partition()] = &consumerState{partitionConsumer: pc}
go c.handleMessages(pc)
go c.handleErrors(pc.Partition(), pc.Errors())
Expand All @@ -86,6 +94,7 @@ func (c *Consumer) Close() error {
c.closePartition(p.partitionConsumer)
p.wg.Wait()
}
c.allPartitionDeadlockDetector.close()
c.logger.Info("Closing parent consumer")
return c.internalConsumer.Close()
}
Expand All @@ -97,27 +106,44 @@ func (c *Consumer) handleMessages(pc sc.PartitionConsumer) {
defer c.closePartition(pc)

msgMetrics := c.newMsgMetrics(pc.Partition())

var msgProcessor processor.SpanProcessor

for msg := range pc.Messages() {
c.logger.Debug("Got msg", zap.Any("msg", msg))
msgMetrics.counter.Inc(1)
msgMetrics.offsetGauge.Update(msg.Offset)
msgMetrics.lagGauge.Update(pc.HighWaterMarkOffset() - msg.Offset - 1)
deadlockDetector := c.deadlockDetectorFactory.startMonitoringForPartition(pc.Partition())
defer deadlockDetector.close()

if msgProcessor == nil {
msgProcessor = c.processorFactory.new(pc.Partition(), msg.Offset-1)
defer msgProcessor.Close()
}
for {
select {
case msg, ok := <-pc.Messages():
if !ok {
c.logger.Info("Message channel closed. ", zap.Int32("partition", pc.Partition()))
return
}
c.logger.Debug("Got msg", zap.Any("msg", msg))
msgMetrics.counter.Inc(1)
msgMetrics.offsetGauge.Update(msg.Offset)
msgMetrics.lagGauge.Update(pc.HighWaterMarkOffset() - msg.Offset - 1)
deadlockDetector.incrementMsgCount()
c.allPartitionDeadlockDetector.incrementMsgCount()
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I don't follow what the purpose of this allPartitionDeadlockDetector is. It looks like it's only used to increment this counter - why do we even need it? We can always sum the time series to get total counter.


if msgProcessor == nil {
msgProcessor = c.processorFactory.new(pc.Partition(), msg.Offset-1)
defer msgProcessor.Close()
yurishkuro marked this conversation as resolved.
Show resolved Hide resolved
}

msgProcessor.Process(&saramaMessageWrapper{msg})

msgProcessor.Process(&saramaMessageWrapper{msg})
case <-deadlockDetector.getClosePartition():
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

s/getClosePartition/closePartitionChannel/

c.logger.Info("Closing partition due to inactivity", zap.Int32("partition", pc.Partition()))
return
}
}
c.logger.Info("Finished handling messages", zap.Int32("partition", pc.Partition()))
}

func (c *Consumer) closePartition(partitionConsumer sc.PartitionConsumer) {
c.logger.Info("Closing partition consumer", zap.Int32("partition", partitionConsumer.Partition()))
partitionConsumer.Close() // blocks until messages channel is drained
vprithvi marked this conversation as resolved.
Show resolved Hide resolved
c.newPartitionMetrics(partitionConsumer.Partition()).closeCounter.Inc(1)
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

why do we call new here? If it internally caches the metrics, then s/newPartitionMetrics/newPartitionMetrics

c.logger.Info("Closed partition consumer", zap.Int32("partition", partitionConsumer.Partition()))
}

Expand Down
20 changes: 17 additions & 3 deletions cmd/ingester/app/consumer/consumer_metrics.go
Original file line number Diff line number Diff line change
Expand Up @@ -30,8 +30,17 @@ type errMetrics struct {
errCounter metrics.Counter
}

type partitionMetrics struct {
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

nit: we should clean-up these metrics. All 3 structs are per-partition, could we not combine them into one? Then we won't have all these small functions on the Consumer.

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I agree - I'll do it as a separate commit

startCounter metrics.Counter
closeCounter metrics.Counter
}

func (c *Consumer) getNamespace(partition int32) metrics.Factory {
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

s/getNamespace/metricsFactoryForPartition/

Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

NB: we don't use "get" in Go.

return c.metricsFactory.Namespace("sarama-consumer", map[string]string{"partition": strconv.Itoa(int(partition))})
}

func (c *Consumer) newMsgMetrics(partition int32) msgMetrics {
f := c.metricsFactory.Namespace("sarama-consumer", map[string]string{"partition": strconv.Itoa(int(partition))})
f := c.getNamespace(partition)
return msgMetrics{
counter: f.Counter("messages", nil),
offsetGauge: f.Gauge("current-offset", nil),
Expand All @@ -40,7 +49,12 @@ func (c *Consumer) newMsgMetrics(partition int32) msgMetrics {
}

func (c *Consumer) newErrMetrics(partition int32) errMetrics {
f := c.metricsFactory.Namespace("sarama-consumer", map[string]string{"partition": strconv.Itoa(int(partition))})
return errMetrics{errCounter: f.Counter("errors", nil)}
return errMetrics{errCounter: c.getNamespace(partition).Counter("errors", nil)}
}

func (c *Consumer) newPartitionMetrics(partition int32) partitionMetrics {
f := c.getNamespace(partition)
return partitionMetrics{
closeCounter: f.Counter("partition-close", nil),
startCounter: f.Counter("partition-start", nil)}
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This still bothers me. Some metrics factories are not happy if you try to create a metric with the same name twice. So if we re-acquire the same partition, this could cause a panic, e.g. if someone is using expvar-based metrics (unless we implemented protection in the factory, which I had to do for Prometheus).

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I added a test to jaeger-lib/metrics which shows that calling Counter mutiple times with the same tags does not panic for expvar, prometheus and tally.

}
41 changes: 37 additions & 4 deletions cmd/ingester/app/consumer/consumer_test.go
Original file line number Diff line number Diff line change
Expand Up @@ -89,11 +89,14 @@ func newConsumer(
consumer consumer.Consumer) *Consumer {

logger, _ := zap.NewDevelopment()
deadlockDetectorFactory := newDeadlockDetectorFactory(factory, logger, time.Second)
return &Consumer{
metricsFactory: factory,
logger: logger,
internalConsumer: consumer,
partitionIDToState: make(map[int32]*consumerState),
metricsFactory: factory,
logger: logger,
internalConsumer: consumer,
partitionIDToState: make(map[int32]*consumerState),
deadlockDetectorFactory: deadlockDetectorFactory,
allPartitionDeadlockDetector: deadlockDetectorFactory.startMonitoringForPartition(-1),

processorFactory: ProcessorFactory{
topic: topic,
Expand Down Expand Up @@ -173,6 +176,11 @@ func TestSaramaConsumerWrapper_start_Messages(t *testing.T) {
Tags: partitionTag,
Value: 0,
})
testutils.AssertCounterMetrics(t, localFactory, testutils.ExpectedMetric{
Name: "sarama-consumer.partition-start",
Tags: partitionTag,
Value: 1,
})
}

func TestSaramaConsumerWrapper_start_Errors(t *testing.T) {
Expand Down Expand Up @@ -210,3 +218,28 @@ func TestSaramaConsumerWrapper_start_Errors(t *testing.T) {

t.Fail()
}

func TestHandleClosePartition(t *testing.T) {
localFactory := metrics.NewLocalFactory(0)
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

s/localFactory/metricsFactory/


mp := &pmocks.SpanProcessor{}
saramaConsumer := smocks.NewConsumer(t, &sarama.Config{})
mc := saramaConsumer.ExpectConsumePartition(topic, partition, msgOffset)
mc.ExpectErrorsDrainedOnClose()
saramaPartitionConsumer, e := saramaConsumer.ConsumePartition(topic, partition, msgOffset)
require.NoError(t, e)

undertest := newConsumer(localFactory, topic, mp, newSaramaClusterConsumer(saramaPartitionConsumer))
undertest.deadlockDetectorFactory = newDeadlockDetectorFactory(localFactory, zap.NewNop(), 10*time.Millisecond)
undertest.Start()
defer undertest.Close()

for i := 0; i < 10; i++ {
time.Sleep(20 * time.Millisecond)
c, _ := localFactory.Snapshot()
if c["sarama-consumer.partition-close|partition=316"] == 1 {
return
}
}
assert.Fail(t, "Did not close partition")
}
127 changes: 127 additions & 0 deletions cmd/ingester/app/consumer/deadlock_detector.go
Original file line number Diff line number Diff line change
@@ -0,0 +1,127 @@
// Copyright (c) 2018 The Jaeger Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package consumer

import (
"runtime"
"strconv"
"sync/atomic"
"time"

"github.com/uber/jaeger-lib/metrics"
"go.uber.org/zap"
)

// deadlockDetectorFactory is a factory for deadlockDetectors
type deadlockDetectorFactory struct {
metricsFactory metrics.Factory
logger *zap.Logger
interval time.Duration
panicFunc func(int32)
}

type deadlockDetector struct {
msgConsumed *uint64
ticker *time.Ticker
logger *zap.Logger
closePartition chan struct{}
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I assume this does not apply to all-partitions detector?

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

It does not

done chan struct{}
}

func newDeadlockDetectorFactory(factory metrics.Factory, logger *zap.Logger, interval time.Duration) deadlockDetectorFactory {
return deadlockDetectorFactory{
metricsFactory: factory,
logger: logger,
interval: interval,
panicFunc: func(partition int32) {
factory.Counter("deadlockdetector.panic-issued", map[string]string{"partition": strconv.Itoa(int(partition))}).Inc(1)
time.Sleep(time.Second) // Allow time to flush metric

buf := make([]byte, 1<<20)
logger.Panic("No messages processed in the last check interval",
zap.Int32("partition", partition),
zap.String("stack", string(buf[:runtime.Stack(buf, true)])))
},
}
}

// startMonitoringForPartition monitors the messages consumed by the partition and signals for the partition to by
// closed by sending a message on the closePartition channel.
//
// Closing the partition should result in a rebalance, which alleviates the condition. This means that rebalances can
// happen frequently if there is no traffic on the Kafka topic. This shouldn't affect normal operations.
//
// If the message send isn't processed within the next check interval, a panic is issued.This hack relies on a
// container management system (k8s, aurora, marathon, etc) to reschedule
// the dead instance.
//
// This hack protects jaeger-ingester from issues described in https://github.com/jaegertracing/jaeger/issues/1052
vprithvi marked this conversation as resolved.
Show resolved Hide resolved
//
func (s *deadlockDetectorFactory) startMonitoringForPartition(partition int32) *deadlockDetector {
var msgConsumed uint64
w := &deadlockDetector{
msgConsumed: &msgConsumed,
ticker: time.NewTicker(s.interval),
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

nit: you do not need to leak the ticker. Create it inside goroutine as local var with defer close.

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

👍

closePartition: make(chan struct{}, 1),
done: make(chan struct{}),
logger: s.logger,
}

go func() {
vprithvi marked this conversation as resolved.
Show resolved Hide resolved
for range w.ticker.C {
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

this is an odd pattern. If you close(done), nothing will happen till the ticker fires. You probably want unconditional for{} and then select across all channels, including the ticker.

select {
case <-w.done:
s.logger.Info("Closing ticker routine", zap.Int32("partition", partition))
return
default:
if atomic.LoadUint64(w.msgConsumed) == 0 {
select {
case w.closePartition <- struct{}{}:
s.logger.Warn("Signalling partition close due to inactivity", zap.Int32("partition", partition))
vprithvi marked this conversation as resolved.
Show resolved Hide resolved
default:
// If closePartition is blocked, the consumer might have deadlocked - kill the process
s.panicFunc(partition)
}
} else {
atomic.StoreUint64(w.msgConsumed, 0)
}
}
}
}()

return w
}

// startMonitoring is to monitor that the sum of messages consumed across all partitions is non zero for the given interval
// If it is zero when there are producers producing messages on the topic, it means that sarama-cluster hasn't
// retrieved partition assignments. (This case will not be caught by startMonitoringForPartition because no partitions
// were retrieved).
func (s *deadlockDetectorFactory) startMonitoring() *deadlockDetector {
return s.startMonitoringForPartition(-1)
}

func (w *deadlockDetector) getClosePartition() chan struct{} {
return w.closePartition
}

func (w *deadlockDetector) close() {
w.logger.Info("Closing deadlock detector")
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

nit: better to capture partition # in the detector and include it in the log stmt

w.done <- struct{}{}
w.ticker.Stop()
}

func (w *deadlockDetector) incrementMsgCount() {
atomic.AddUint64(w.msgConsumed, 1)
}
Loading