This document provides instructions for installing and configuring a Zookeeper cluster on Ubuntu 18.04. It describes how to install Java, create a user, download and extract the Zookeeper files, configure the zoo.cfg file, add systemd services, and start Zookeeper. It also provides details for configuring a multi-node Zookeeper cluster, including modifying the zoo.cfg file to list the servers and changing the server IDs in the data directory.
Written for getting up to date with Node.js:
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Node.js API
Node.js is an open-source, cross-platform, back-end, JavaScript runtime environment that executes JavaScript code outside a web browser. Node.js lets developers use JavaScript to write command line tools and for server-side scripting—running scripts server-side to produce dynamic web page content before the page is sent to the user's web browser. Consequently, Node.js represents a "JavaScript everywhere" paradigm,[6] unifying web-application development around a single programming language, rather than different languages for server- and client-side scripts.
Written for getting up to date with Node.js:
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Node.js API
Node.js is an open-source, cross-platform, back-end, JavaScript runtime environment that executes JavaScript code outside a web browser. Node.js lets developers use JavaScript to write command line tools and for server-side scripting—running scripts server-side to produce dynamic web page content before the page is sent to the user's web browser. Consequently, Node.js represents a "JavaScript everywhere" paradigm,[6] unifying web-application development around a single programming language, rather than different languages for server- and client-side scripts.
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# Internet Security: Safeguarding Your Digital World
In the contemporary digital age, the internet is a cornerstone of our daily lives. It connects us to vast amounts of information, provides platforms for communication, enables commerce, and offers endless entertainment. However, with these conveniences come significant security challenges. Internet security is essential to protect our digital identities, sensitive data, and overall online experience. This comprehensive guide explores the multifaceted world of internet security, providing insights into its importance, common threats, and effective strategies to safeguard your digital world.
## Understanding Internet Security
Internet security encompasses the measures and protocols used to protect information, devices, and networks from unauthorized access, attacks, and damage. It involves a wide range of practices designed to safeguard data confidentiality, integrity, and availability. Effective internet security is crucial for individuals, businesses, and governments alike, as cyber threats continue to evolve in complexity and scale.
### Key Components of Internet Security
1. **Confidentiality**: Ensuring that information is accessible only to those authorized to access it.
2. **Integrity**: Protecting information from being altered or tampered with by unauthorized parties.
3. **Availability**: Ensuring that authorized users have reliable access to information and resources when needed.
## Common Internet Security Threats
Cyber threats are numerous and constantly evolving. Understanding these threats is the first step in protecting against them. Some of the most common internet security threats include:
### Malware
Malware, or malicious software, is designed to harm, exploit, or otherwise compromise a device, network, or service. Common types of malware include:
- **Viruses**: Programs that attach themselves to legitimate software and replicate, spreading to other programs and files.
- **Worms**: Standalone malware that replicates itself to spread to other computers.
- **Trojan Horses**: Malicious software disguised as legitimate software.
- **Ransomware**: Malware that encrypts a user's files and demands a ransom for the decryption key.
- **Spyware**: Software that secretly monitors and collects user information.
### Phishing
Phishing is a social engineering attack that aims to steal sensitive information such as usernames, passwords, and credit card details. Attackers often masquerade as trusted entities in email or other communication channels, tricking victims into providing their information.
### Man-in-the-Middle (MitM) Attacks
MitM attacks occur when an attacker intercepts and potentially alters communication between two parties without their knowledge. This can lead to the unauthorized acquisition of sensitive information.
### Denial-of-Service (DoS) and Distributed Denial-of-Service (DDoS) Attacks
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2. 2/2
sudo vi /data/zookeeper/myid # - Change server ID in dataDir (ex: 1,2,3) for all nodes
cd /opt/zookeeper
java -cp zookeeper-3.4.14.jar:lib/log4j-1.2.17.jar:lib/slf4j-log4j12-1.7.25.jar:lib/slf4j-
api-1.7.25.jar:conf org.apache.zookeeper.server.quorum.QuorumPeerMain conf/zoo.cfg - Смотреть логи в
риалтайме
![1/2
Zookeper
https://www.digitalocean.com/community/tutorials/how-to-install-and-configure-an-apache-zookeeper-cluster-on-
ubuntu-18-04
Install Zookeeper (min 3 node)
yum install java-1.8.0-openjdk
sudo useradd zk -m
sudo usermod --shell /bin/bash zk
sudo passwd zk
usermod -aG sudo zk or sudo visudo
sudo mkdir -p /data/zookeeper
sudo chown zk:zk /data/zookeeper
cd /opt
wget https://www-us.apache.org/dist/zookeeper/zookeeper-3.4.14/zookeeper-3.4.14.tar.gz
tar -zxvf zookeeper-3.4.14.tar.gz
sudo chown zk:zk -R zookeeper-xx.xx.xx
sudo ln -s zookeeper-3.4.14 zookeeper
sudo chown -h zk:zk zookeeper
sudo vi /opt/zookeeper/conf/zoo.cfg
tickTime=2000
initLimit=10
syncLimit=5
dataDir=/data/zookeeper
# dataLogDir=/tmp/zookeeper-log
clientPort=2181
maxClientCnxns=60
:wq
cd /opt/zookeeper
bin/zkServer.sh start
bin/zkServer.sh stop
sudo vi /etc/systemd/system/zk.service
[Unit]
Description=Zookeeper Daemon
Documentation=http://zookeeper.apache.org
Requires=network.target
After=network.target
[Service]
Type=forking
WorkingDirectory=/opt/zookeeper
User=zk
Group=zk
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
:wq
sudo systemctl start zk
sudo systemctl enable zk
sudo systemctl status zk
sudo systemctl restart zk
FOR Multi-Node ZooKeeper Cluster
sudo vi /opt/zookeeper/conf/zoo.cfg
tickTime=2000
dataDir=/data/zookeeper
clientPort=2181
maxClientCnxns=60
initLimit=10
syncLimit=5
server.1=your_zookeeper_node_1:2888:3888
server.2=your_zookeeper_node_2:2888:3888
server.3=your_zookeeper_node_3:2888:3888
:wq](https://image.slidesharecdn.com/zookeper-190724052749/85/Zookeper-1-320.jpg)
