How To Install Apache ZooKeeper on Ubuntu 20.04 LTS

In this tutorial, we will show you how to install Apache ZooKeeper on Ubuntu 20.04 LTS. For those of you who didn’t know, ZooKeeper is a software project by Apache Software Foundation that provides high-performance shared data, maintaining configuration information, naming, providing synchronization, and providing group services. In addition, distributed systems rely on ZooKeeper to implement consensus, leader election, and group management.

This article assumes you have at least basic knowledge of Linux, know how to use the shell, and most importantly, you host your site on your own VPS. The installation is quite simple and assumes you are running in the root account, if not you may need to add ‘sudo‘ to the commands to get root privileges. I will show you the step-by-step installation of the Apache ZooKeeper on Ubuntu 20.04 (Focal Fossa). You can follow the same instructions for Ubuntu 18.04, 16.04, and any other Debian-based distribution like Linux Mint.

Prerequisites

• A server running one of the following operating systems: Ubuntu 20.04, 18.04, and any other Debian-based distribution like Linux Mint or elementary OS.
• It’s recommended that you use a fresh OS install to prevent any potential issues.
• SSH access to the server (or just open Terminal if you’re on a desktop).
• A non-root sudo user or access to the root user. We recommend acting as a non-root sudo user, however, as you can harm your system if you’re not careful when acting as the root.

Install Apache ZooKeeper on Ubuntu 20.04 LTS Focal Fossa

Step 1. First, make sure that all your system packages are up-to-date by running the following apt commands in the terminal.

sudo apt update
sudo apt upgrade

Step 2. Installing Java.

Zookeeper is written in Java and requires this programming language to work. You can install it with the following command:

sudo apt install default-jdk

Verify the installed version of Java:

java --version

Step 3. Create a User for Zookeeper.

We need to create a user that will run all the ZooKeeper services:

useradd zookeeper -m

Next, set password for this user and add it to the sudo group with the following command:

usermod --shell /bin/bash zookeeper
passwd zookeeper
usermod -aG sudo zookeeper

Then, change the ownership of this directory:

mkdir /zookeeper
chown -R zookeeper:zookeeper /zookeeper

Step 4. Installing Apache ZooKeeper on Ubuntu 20.04.

By default, Apache ZooKeeper is available on Ubuntu 20.04 base repository. Now run the following command below to download the latest ZooKeeper to your Ubuntu system:

wget https://www.apache.org/dyn/closer.lua/zookeeper/zookeeper-3.8.0/apache-zookeeper-3.8.0-bin.tar.gz

Next, extract the downloaded file:

tar -xvzf apache-zookeeper-3.8.0-bin.tar.gz
mv apache-zookeeper-3.8.0-bin zookeeper

Give the zookeeper user ownership of that file by running:

chown -R zookeeper:zookeeper /opt/zookeeper

Step 5. Configure ZooKeeper Standalone Mode.

Now we create a ZooKeeper configuration file to sets up ZooKeeper in standalone mode:

nano /opt/zookeeper/conf/zoo.cfg

Add the following lines:

tickTime=2500
dataDir=/zookeeper
clientPort=2181
maxClientCnxns=80

Save and close the file, then start the ZooKeeper service with the following command:

cd /opt/zookeeper
bin/zkServer.sh start

Step 6. Create a Systemd Service File for ZooKeeper.

Now we create a systemd service file to manage the ZooKeeper service:

nano /etc/systemd/system/zookeeper.service

Add the following lines:

[Unit]
Description=Zookeeper Daemon
Documentation=http://zookeeper.apache.org
Requires=network.target
After=network.target

[Service]    
Type=forking
WorkingDirectory=/opt/zookeeper
User=zookeeper
Group=zookeeper
ExecStart=/opt/zookeeper/bin/zkServer.sh start /opt/zookeeper/conf/zoo.cfg
ExecStop=/opt/zookeeper/bin/zkServer.sh stop /opt/zookeeper/conf/zoo.cfg
ExecReload=/opt/zookeeper/bin/zkServer.sh restart /opt/zookeeper/conf/zoo.cfg
TimeoutSec=30
Restart=on-failure

[Install]
WantedBy=default.target

Save and close the file, then reload the systemd daemon to apply the configuration changes:

sudo systemctl daemon-reload
sudo systemctl start zookeeper
sudo systemctl enable zookeeper

Finally, change the ownership of the ZooKeeper and data directory with the following command:

chown -R zookeeper:zookeeper /opt/zookeeper
chown -R zookeeper:zookeeper /zookeeper

Congratulations! You have successfully installed Apache ZooKeeper. Thanks for using this tutorial for installing the Apache ZooKeeper on Ubuntu 20.04 LTS Focal Fossa system. For additional help or useful information, we recommend you check the official Apache website.