# Install Kafka needs Zookeer in order to run. ``` ➜ brew install zookeeper ➜ brew services start zookeper ``` We can instal and run Kafka the same way. ``` ➜ brew install kafka ➜ brew services start kafka ``` When both are started, we can validate what all services are running on our system. ``` ➜ brew services list Name Status User Plist zookeeper started ondrej /Users/ondrej/Library/LaunchAgents/homebrew.mxcl.zookeeper.plist kafka started ondrej /Users/ondrej/Library/LaunchAgents/homebrew.mxcl.kafka.plist ``` Now we need to find where is Kafka installed so we can access its tools. ``` ➜ brew --prefix kafka /usr/local/opt/kafka ``` Add it to your profile, for example, if you use zsh, add this line into your `vi ~/.zshrc`. ``` # Kafka export PATH=/usr/local/opt/kafka/bin:$PATH ``` Don't forget to reload the config: `source ~/.zshrc` Now we can try out whether we can access Kafka commands. Lets try to list all topics that are present in Kafka. ``` ➜ kafka-topics --list --zookeeper localhost:2181 __consumer_offsets ``` ## Setup multi-broker cluster We have managed to run single broker. Lets see how to configure and start up multiple Kafka brokers. ``` ➜ cp /usr/local/etc/kafka/server.properties broker1.properties ➜ cp /usr/local/etc/kafka/server.properties broker2.properties ``` Because we are going to run brokers on the same machine, we need to change these in `broker1.properties` ``` broker.id=1 listeners=PLAINTEXT://:9093 log.dirs=/usr/local/var/lib/kafka-logs-1 ``` And these in `broker2.properties` ``` broker.id=2 listeners=PLAINTEXT://:9094 log.dirs=/usr/local/var/lib/kafka-logs-2 ``` Now we can start up the two brokers we made the configuration for. ``` ➜ /usr/local/opt/kafka/bin/kafka-server-start broker1.properties & ➜ /usr/local/opt/kafka/bin/kafka-server-start broker2.properties & ``` We can create topic that will be using 3 brokers we have started up so far. ``` ➜ kafka-topics --create \ --zookeeper localhost:2181 \ --replication-factor 3 \ --partitions 1 \ --topic my-replicated-topic Created topic "my-replicated-topic". ``` We can see what is happening in the cluster using `describe topics` command. ``` ➜ kafka-topics --describe \ --zookeeper localhost:2181 \ --topic my-replicated-topic Topic:my-replicated-topic PartitionCount:1 ReplicationFactor:3 Configs: Topic: my-replicated-topic Partition: 0 Leader: 1 Replicas: 1,2,0 Isr: 1,2,0 ``` * leader is node that is responsible for all reads and writes for given partition, if we would set partitions to 2, we would see two lines here * replicas - list of all nodes that replicate the log for this partition * isr - in-sync replicas, or "alive" replicas If we want to kill the nodes we created, we first get the process id and then kill it. ``` ➜ ps aux | grep broker1.properties ondrej 66855 0.0 1.8...... .... ➜ kill -9 66855 ``` Now we can check what --describe command returns when we run it again, after we have killed one broker. ``` ➜ kafka-topics --describe \ --zookeeper localhost:2181 \ --topic my-replicated-topic Topic:my-replicated-topic PartitionCount:1 ReplicationFactor:3 Configs: Topic: my-replicated-topic Partition: 0 Leader: 2 Replicas: 1,2,0 Isr: 2,0 ``` --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://ondrej-kvasnovsky-2.gitbook.io/kafka-handbook/chapter1.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.