KafkaHealthcheck

KafkaHealthcheck registers the broker it runs on with Zookeeper (which in turn makes the broker visible to other brokers that together can form a Kafka cluster).

KafkaHealthcheck is created and started when KafkaServer is requested to start up.

Figure 1. KafkaHealthcheck

Table 1. KafkaHealthcheck’s Internal Properties (e.g. Registries and Counters)
Name	Description
`sessionExpireListener`	`SessionExpireListener`

Creating KafkaHealthcheck Instance

KafkaHealthcheck takes the following when created:

Broker ID
Advertised endpoints
ZkUtils
Optional rack name
ApiVersion

KafkaHealthcheck initializes the internal registries and counters.

Starting Up — `startup` Method

startup

startup requests ZkUtils to subscribeStateChanges with sessionExpireListener.

In the end, startup registers the broker with Zookeeper.

Note	`startup` is used exclusively when `KafkaServer` starts up.

Registering Broker in Zookeeper — `register` Method

register(): Unit

register reads com.sun.management.jmxremote.port System property or defaults to -1.

For every EndPoint with no host assigned (in advertisedEndpoints), register assigns the fully-qualified domain name of the local host.

register then finds the first EndPoint with PLAINTEXT security protocol or creates an empty EndPoint.

Tip	Define `EndPoint` with `PLAINTEXT` security protocol for older clients to connect.

In the end, register requests ZkUtils to registerBrokerInZk for brokerId, the host and port of the PLAINTEXT endpoint, the updated endpoints, the JMX port, the optional rack and protocol version.

Note	`register` makes a broker visible for other brokers to form a Kafka cluster.

Note	`register` is used when `KafkaHealthcheck` starts up and handles a new session.

`handleNewSession` Method

Caution

FIXME

KafkaHealthcheck