> ## Documentation Index > Fetch the complete documentation index at: https://notes.kodekloud.com/llms.txt > Use this file to discover all available pages before exploring further. # Demo Kafka Setup with Zookeeper > Guide to installing and running Apache Kafka with ZooKeeper on CentOS, showing download, configuration, starting services, and verifying Kafka connects to ZooKeeper Welcome — this guide walks through setting up Apache Kafka with ZooKeeper on a CentOS (or similar) Linux host. It explains how Kafka depends on ZooKeeper, how to start both services, and how to verify they are communicating. Prerequisite * A CentOS machine (or similar Linux host) with network access to download Kafka binaries. Step 1 — Download and extract Kafka Download the Kafka 3.0.0 binary and extract it: ```bash theme={null} bob@centos-host ~ $ wget https://archive.apache.org/dist/kafka/3.0.0/kafka_2.13-3.0.0.tgz bob@centos-host ~ $ tar -xzf kafka_2.13-3.0.0.tgz ``` List and change into the extracted directory: ```bash theme={null} bob@centos-host ~ $ ls -lrt total 84380 drwxr-xr-x 7 bob bob 4096 Sep 20 2021 kafka_2.13-3.0.0 bob@centos-host ~ $ cd kafka_2.13-3.0.0/ bob@centos-host ~/kafka_2.13-3.0.0 $ ls -lrt total 64 -rw-r--r-- 1 bob bob 28184 Sep 8 2021 NOTICE -rw-r--r-- 1 bob bob 14521 Sep 8 2021 LICENSE drwxr-xr-x 2 bob bob 4096 Sep 8 2021 config drwxr-xr-x 3 bob bob 4096 Sep 8 2021 bin drwxr-xr-x 2 bob bob 4096 Apr 16 18:06 site-docs drwxr-xr-x 2 bob bob 4096 Apr 16 18:06 libs ``` Notes: * All start/stop scripts are in the `bin` directory. * Default configuration files live in `config`. Step 2 — Inspect ZooKeeper-related scripts Change into `bin` and list ZooKeeper scripts: ```bash theme={null} bob@centos-host ~/kafka_2.13-3.0.0 $ cd bin bob@centos-host ~/kafka_2.13-3.0.0/bin $ ls -lrt | grep zookeeper -rwxr-xr-x 1 bob bob 1019 Sep 8 2021 zookeeper-shell.sh -rwxr-xr-x 1 bob bob 1366 Sep 8 2021 zookeeper-server-stop.sh -rwxr-xr-x 1 bob bob 1393 Sep 8 2021 zookeeper-server-start.sh -rwxr-xr-x 1 bob bob 867 Sep 8 2021 zookeeper-security-migration.sh ``` Quick reference table for the files you’ll use: | File | Purpose | Example usage | | --------------------------- | ---------------------------------------------------- | ----------------------------------------------------------- | | `zookeeper-server-start.sh` | Starts a standalone ZooKeeper server (used by Kafka) | `bin/zookeeper-server-start.sh config/zookeeper.properties` | | `zookeeper-server-stop.sh` | Stops the ZooKeeper server | `bin/zookeeper-server-stop.sh` | | `zookeeper-shell.sh` | A shell client for interacting with ZooKeeper | `bin/zookeeper-shell.sh localhost:2181` | Step 3 — Inspect the default ZooKeeper config The default ZooKeeper configuration file is `config/zookeeper.properties`. List the config directory: ```bash theme={null} bob@centos-host ~/kafka_2.13-3.0.0/bin $ cd ../config bob@centos-host ~/kafka_2.13-3.0.0/config $ ls -lrt total 76 -rw-r--r-- 1 bob bob 1205 Sep 8 2021 zookeeper.properties -rw-r--r-- 1 bob bob 2547 Sep 8 2021 server.properties ... ``` What to check in `zookeeper.properties`: * Client port (default: `2181`) * Data directory (`dataDir`) * Clustering settings (if running an ensemble) Step 4 — Start ZooKeeper You can start ZooKeeper either from the Kafka root or from the `bin` directory. Example — start from Kafka root: ```bash theme={null} bob@centos-host ~/kafka_2.13-3.0.0 $ bin/zookeeper-server-start.sh config/zookeeper.properties ``` Example — start from `bin` directory: ```bash theme={null} bob@centos-host ~/kafka_2.13-3.0.0/bin $ ./zookeeper-server-start.sh ../config/zookeeper.properties ``` Tip: If you see a path-related error, confirm the relative path to `zookeeper.properties` matches your current working directory. ZooKeeper startup logs (stdout) include lines such as: ```text theme={null} [2025-04-16 18:09:25,198] INFO Binding to port 0.0.0.0:2181 (org.apache.zookeeper.server.NIOServerCnxnFactory) [2025-04-16 18:09:25,376] INFO Snapshot loaded in 14 ms, highest zxid is 0x1 (org.apache.zookeeper.server.snapshot.SnapshotLog) [2025-04-16 18:09:25,484] INFO ZooKeeper audit is disabled. (org.apache.zookeeper.server.auth.XKAuditProvider) ``` By default ZooKeeper listens on port 2181 (the client port). Kafka connects to ZooKeeper on that port unless you change `zookeeper.connect` in Kafka’s `server.properties`. Step 5 — Start the Kafka broker (in a new terminal) Open a second terminal, change into the Kafka folder, and start the broker: ```bash theme={null} bob@centos-host ~ $ cd kafka_2.13-3.0.0 bob@centos-host ~/kafka_2.13-3.0.0 $ bin/kafka-server-start.sh config/server.properties ``` During startup Kafka reads `server.properties`. By default it contains: ```text theme={null} zookeeper.connect = localhost:2181 zookeeper.session.timeout.ms = 18000 ``` Watch the broker logs for confirmation it started and connected to ZooKeeper: ```text theme={null} [2025-04-16 18:10:55,688] INFO Loaded logs to directory /tmp/kafka-logs (kafka.log.LogManager) [2025-04-16 18:10:56,763] INFO Starting log cleanup with a period of 300000 ms. (kafka.log.LogManager) [2025-04-16 18:10:56,687] INFO [BrokerToControllerChannelManager broker=...] Starting (kafka.server.BrokerToControllerRequestThread) ``` Troubleshooting * If Kafka cannot connect to ZooKeeper, it will fail during broker initialization. Confirm: * ZooKeeper is running and reachable on the address in `zookeeper.connect`. * Network/iptables allow traffic to port `2181`. * The `server.properties` and `zookeeper.properties` file paths are correct when launching the scripts. Conclusion This demo covered: * Downloading and extracting Kafka binaries * Locating ZooKeeper startup scripts and configuration files * Starting ZooKeeper and verifying it binds to port 2181 * Starting the Kafka broker and confirming it connects to ZooKeeper Further reading and references * [Apache Kafka Documentation](https://kafka.apache.org/documentation/) * [ZooKeeper Documentation](https://zookeeper.apache.org/doc/current/) * [Kubernetes Basics](https://kubernetes.io/docs/concepts/overview/what-is-kubernetes/)