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Posted to jira@kafka.apache.org by "Jason Gustafson (Jira)" <ji...@apache.org> on 2021/11/09 21:46:00 UTC
[jira] [Updated] (KAFKA-13417) Dynamic thread pool
re-configurations may not get processed
[ https://issues.apache.org/jira/browse/KAFKA-13417?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Jason Gustafson updated KAFKA-13417:
------------------------------------
Description:
`DynamicBrokerConfig.updateCurrentConfig` includes the following logic to update the current configuration and to let each `Reconfigurable` process the update:
{code}
val oldConfig = currentConfig
val (newConfig, brokerReconfigurablesToUpdate) = processReconfiguration(newProps, validateOnly = false)
if (newConfig ne currentConfig) {
currentConfig = newConfig
kafkaConfig.updateCurrentConfig(newConfig)
// Process BrokerReconfigurable updates after current config is updated
brokerReconfigurablesToUpdate.foreach(_.reconfigure(oldConfig, newConfig))
}
{code}
The problem here is that `currentConfig` gets initialized as `kafkaConfig` which means that the first call to `kafkaConfig.updateCurrentConfig(newConfig)` ends up mutating `currentConfig` and consequently `oldConfig`. The problem with this is that some of the `reconfigure` implementations will only apply a new configuration if the value in `oldConfig` does not match the value in `newConfig`. For example, here is the logic to update thread pools dynamically:
{code}
override def reconfigure(oldConfig: KafkaConfig, newConfig: KafkaConfig): Unit = {
if (newConfig.numIoThreads != oldConfig.numIoThreads)
server.dataPlaneRequestHandlerPool.resizeThreadPool(newConfig.numIoThreads)
if (newConfig.numNetworkThreads != oldConfig.numNetworkThreads)
server.socketServer.resizeThreadPool(oldConfig.numNetworkThreads, newConfig.numNetworkThreads)
if (newConfig.numReplicaFetchers != oldConfig.numReplicaFetchers)
server.replicaManager.replicaFetcherManager.resizeThreadPool(newConfig.numReplicaFetchers)
if (newConfig.numRecoveryThreadsPerDataDir != oldConfig.numRecoveryThreadsPerDataDir)
server.logManager.resizeRecoveryThreadPool(newConfig.numRecoveryThreadsPerDataDir)
if (newConfig.backgroundThreads != oldConfig.backgroundThreads)
server.kafkaScheduler.resizeThreadPool(newConfig.backgroundThreads)
}
{code}
Because of this, the dynamic update will not get applied the first time it is made. I believe subsequent updates would work correctly though because we would have lost the indirect reference to `kafkaConfig`. Other than the `DynamicThreadPool` configurations, it looks like the config to update unclean leader election may also be affected by this bug.
NOTE: This bug only affects kraft, which is missing the call to `DynamicBrokerConfig.initialize()`.
was:
`DynamicBrokerConfig.updateCurrentConfig` includes the following logic to update the current configuration and to let each `Reconfigurable` process the update:
{code}
val oldConfig = currentConfig
val (newConfig, brokerReconfigurablesToUpdate) = processReconfiguration(newProps, validateOnly = false)
if (newConfig ne currentConfig) {
currentConfig = newConfig
kafkaConfig.updateCurrentConfig(newConfig)
// Process BrokerReconfigurable updates after current config is updated
brokerReconfigurablesToUpdate.foreach(_.reconfigure(oldConfig, newConfig))
}
{code}
The problem here is that `currentConfig` gets initialized as `kafkaConfig` which means that the first call to `kafkaConfig.updateCurrentConfig(newConfig)` ends up mutating `currentConfig` and consequently `oldConfig`. The problem with this is that some of the `reconfigure` implementations will only apply a new configuration if the value in `oldConfig` does not match the value in `newConfig`. For example, here is the logic to update thread pools dynamically:
{code}
override def reconfigure(oldConfig: KafkaConfig, newConfig: KafkaConfig): Unit = {
if (newConfig.numIoThreads != oldConfig.numIoThreads)
server.dataPlaneRequestHandlerPool.resizeThreadPool(newConfig.numIoThreads)
if (newConfig.numNetworkThreads != oldConfig.numNetworkThreads)
server.socketServer.resizeThreadPool(oldConfig.numNetworkThreads, newConfig.numNetworkThreads)
if (newConfig.numReplicaFetchers != oldConfig.numReplicaFetchers)
server.replicaManager.replicaFetcherManager.resizeThreadPool(newConfig.numReplicaFetchers)
if (newConfig.numRecoveryThreadsPerDataDir != oldConfig.numRecoveryThreadsPerDataDir)
server.logManager.resizeRecoveryThreadPool(newConfig.numRecoveryThreadsPerDataDir)
if (newConfig.backgroundThreads != oldConfig.backgroundThreads)
server.kafkaScheduler.resizeThreadPool(newConfig.backgroundThreads)
}
{code}
Because of this, the dynamic update will not get applied the first time it is made. I believe subsequent updates would work correctly though because we would have lost the indirect reference to `kafkaConfig`. Other than the `DynamicThreadPool` configurations, it looks like the config to update unclean leader election may also be affected by this bug.
> Dynamic thread pool re-configurations may not get processed
> -----------------------------------------------------------
>
> Key: KAFKA-13417
> URL: https://issues.apache.org/jira/browse/KAFKA-13417
> Project: Kafka
> Issue Type: Bug
> Reporter: Jason Gustafson
> Assignee: Jason Gustafson
> Priority: Major
>
> `DynamicBrokerConfig.updateCurrentConfig` includes the following logic to update the current configuration and to let each `Reconfigurable` process the update:
> {code}
> val oldConfig = currentConfig
> val (newConfig, brokerReconfigurablesToUpdate) = processReconfiguration(newProps, validateOnly = false)
> if (newConfig ne currentConfig) {
> currentConfig = newConfig
> kafkaConfig.updateCurrentConfig(newConfig)
> // Process BrokerReconfigurable updates after current config is updated
> brokerReconfigurablesToUpdate.foreach(_.reconfigure(oldConfig, newConfig))
> }
> {code}
> The problem here is that `currentConfig` gets initialized as `kafkaConfig` which means that the first call to `kafkaConfig.updateCurrentConfig(newConfig)` ends up mutating `currentConfig` and consequently `oldConfig`. The problem with this is that some of the `reconfigure` implementations will only apply a new configuration if the value in `oldConfig` does not match the value in `newConfig`. For example, here is the logic to update thread pools dynamically:
> {code}
> override def reconfigure(oldConfig: KafkaConfig, newConfig: KafkaConfig): Unit = {
> if (newConfig.numIoThreads != oldConfig.numIoThreads)
> server.dataPlaneRequestHandlerPool.resizeThreadPool(newConfig.numIoThreads)
> if (newConfig.numNetworkThreads != oldConfig.numNetworkThreads)
> server.socketServer.resizeThreadPool(oldConfig.numNetworkThreads, newConfig.numNetworkThreads)
> if (newConfig.numReplicaFetchers != oldConfig.numReplicaFetchers)
> server.replicaManager.replicaFetcherManager.resizeThreadPool(newConfig.numReplicaFetchers)
> if (newConfig.numRecoveryThreadsPerDataDir != oldConfig.numRecoveryThreadsPerDataDir)
> server.logManager.resizeRecoveryThreadPool(newConfig.numRecoveryThreadsPerDataDir)
> if (newConfig.backgroundThreads != oldConfig.backgroundThreads)
> server.kafkaScheduler.resizeThreadPool(newConfig.backgroundThreads)
> }
> {code}
> Because of this, the dynamic update will not get applied the first time it is made. I believe subsequent updates would work correctly though because we would have lost the indirect reference to `kafkaConfig`. Other than the `DynamicThreadPool` configurations, it looks like the config to update unclean leader election may also be affected by this bug.
> NOTE: This bug only affects kraft, which is missing the call to `DynamicBrokerConfig.initialize()`.
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