kafka-server-DynamicConfigManager.adoc

DynamicConfigManager — Dynamic Configuration Management

DynamicConfigManager monitors (indirectly through the ZkNodeChangeNotificationListener) for any child node changes under /config/changes path in Zookeeper.

DynamicConfigManager uses the ZkNodeChangeNotificationListener (that in turn uses the NotificationHandler) to process configuration change notifications using ConfigHandlers.

DynamicConfigManager is created and immediately started up when KafkaServer is requested to start up.

When created, DynamicConfigManager is given the ConfigHandlers to use (directly from KafkaServer).

DynamicConfigManager uses the feature of Zookeeper called Sequence Nodes with config_change sequence number prefix.

Tip	Read up on Sequence Nodes in the official documentation of Apache Zookeeper.

Creating DynamicConfigManager Instance

DynamicConfigManager takes the following to be created:

• KafkaZkClient

• ConfigHandlers by name

• changeExpirationMs (default: 15 mins)

• Time

Note	changeExpirationMs seems never used.

DynamicConfigManager initializes the internal properties.

startup Method

startup

startup…​FIXME

Note	startup is used exclusively when KafkaServer is requested to start up.

ConfigChangedNotificationHandler Object

ConfigChangedNotificationHandler is a NotificationHandler that processNotification.

Processing Config Change Notifications — processNotification Method

processNotification(jsonBytes: Array[Byte]): Unit

Note	processNotification is part of the NotificationHandler Contract to handle a change notification.

processNotification…​FIXME

processEntityConfigChangeVersion1 Internal Method

processEntityConfigChangeVersion1(jsonBytes: Array[Byte], js: JsonObject): Unit

processEntityConfigChangeVersion1…​FIXME

Note	processEntityConfigChangeVersion1 is used when…​FIXME

processEntityConfigChangeVersion2 Internal Method

processEntityConfigChangeVersion2(jsonBytes: Array[Byte], js: JsonObject): Unit

processEntityConfigChangeVersion2…​FIXME

Note	processEntityConfigChangeVersion2 is used when…​FIXME

Shutting Down — shutdown Method

shutdown(): Unit

shutdown simply requests the ZkNodeChangeNotificationListener to close.

Note	shutdown is used exclusively when KafkaServer is requested to shut down.

Internal Properties

Name	Description
adminZkClient	AdminZkClient (for the KafkaZkClient) Used when: ConfigChangedNotificationHandler is requested to processEntityConfigChangeVersion1 and processEntityConfigChangeVersion2 DynamicConfigManager is requested to start up
configChangeListener	ZkNodeChangeNotificationListener (for the KafkaZkClient and /config/changes path in Zookeeper, config_change sequence number prefix and the ConfigChangedNotificationHandler) Initialized when DynamicConfigManager is requested to start up Closed when DynamicConfigManager is requested to shut down