Installing Nexus Repository Manager on RHEL/CentOS

This guide provides comprehensive instructions for installing Sonatype Nexus Repository Manager 3 on Red Hat Enterprise Linux (RHEL) and CentOS systems.

Prerequisites

Before starting the installation, ensure your system meets the following requirements:

• Operating System: RHEL 7/8/9 or CentOS 7/8/9
• Java: OpenJDK 8 or 11 (Java 8 minimum required)
• Memory: Minimum 4GB RAM (8GB+ recommended for production)
• Disk Space: Minimum 10GB (varies based on repository usage)
• Network: Internet access for downloading packages
• User Privileges: Root or sudo access

Installation Steps

Step 1: Update System and Install Dependencies

Update your system packages and install essential tools:

sudo yum update -y
sudo yum install wget curl unzip java-11-openjdk java-11-openjdk-devel -y

Verify Java installation:

java -version

Step 2: Create Nexus User

Create a dedicated system user for running Nexus:

sudo useradd --system --no-create-home --shell /bin/false nexus

Step 3: Download Nexus Repository Manager

Navigate to the installation directory and download the latest version:

cd /opt
sudo wget https://download.sonatype.com/nexus/3/latest-unix.tar.gz

Extract the downloaded archive:

sudo tar -xzf latest-unix.tar.gz
sudo rm latest-unix.tar.gz

The extraction creates two directories: - nexus-<version>/ - Contains the Nexus application - sonatype-work/ - Contains data and configuration files

Step 4: Create Symbolic Link

Create a symbolic link for easier version management:

sudo ln -s nexus-3.* nexus

Step 5: Set Ownership and Permissions

Change ownership to the nexus user:

sudo chown -R nexus:nexus /opt/nexus*
sudo chown -R nexus:nexus /opt/sonatype-work

Step 6: Configure Nexus Environment

Edit the Nexus configuration file:

sudo vim /opt/nexus/bin/nexus.rc

Uncomment and set the run-as user:

run_as_user="nexus"

Step 7: Configure JVM Settings (Optional)

For production environments, adjust JVM settings in /opt/nexus/bin/nexus.vmoptions:

sudo vim /opt/nexus/bin/nexus.vmoptions

Example production settings:

-Xms2g
-Xmx2g
-XX:MaxDirectMemorySize=3g
-XX:+UnlockExperimentalVMOptions
-XX:+UseCGroupMemoryLimitForHeap
-Djava.util.prefs.userRoot=${NEXUS_DATA}/javaprefs

Step 8: Create Systemd Service

Create a systemd service file for automatic startup:

sudo vim /etc/systemd/system/nexus.service

Add the following configuration:

[Unit]
Description=Nexus Repository Manager
After=network.target

[Service]
Type=forking
LimitNOFILE=65536
ExecStart=/opt/nexus/bin/nexus start
ExecStop=/opt/nexus/bin/nexus stop
User=nexus
Restart=on-abort
TimeoutSec=600

[Install]
WantedBy=multi-user.target

Step 9: Enable and Start Nexus Service

Enable and start the Nexus service:

sudo systemctl daemon-reload
sudo systemctl enable nexus
sudo systemctl start nexus

Check service status:

sudo systemctl status nexus

Step 10: Configure Firewall

Open the required port (8081 by default):

sudo firewall-cmd --permanent --add-port=8081/tcp
sudo firewall-cmd --reload

sudo iptables -I INPUT -p tcp --dport 8081 -j ACCEPT
sudo service iptables save

Step 11: Access Nexus Web Interface

Open your web browser and navigate to:

http://your-server-ip:8081

Post-Installation Configuration

Retrieve Initial Admin Password

sudo cat /opt/sonatype-work/nexus3/admin.password

Setup Wizard

After first login, Nexus will guide you through:

1. Change admin password
2. Configure anonymous access
3. Setup repositories

Service Management

Common service management commands:

# Start Nexus
sudo systemctl start nexus

# Stop Nexus
sudo systemctl stop nexus

# Restart Nexus
sudo systemctl restart nexus

# View service status
sudo systemctl status nexus

# View logs
sudo journalctl -u nexus -f

Troubleshooting

Common Issues

Service won't start:

• Check Java installation: java -version
• Verify file ownership: ls -la /opt/nexus*
• Review logs: sudo journalctl -u nexus -n 50

Web interface not accessible:

• Confirm service is running: sudo systemctl status nexus
• Check firewall settings
• Verify port binding: sudo netstat -tlnp | grep 8081

Performance issues:

• Review JVM settings in nexus.vmoptions
• Monitor system resources: htop or top
• Check disk space: df -h

Log Locations

• Service logs: journalctl -u nexus
• Application logs: /opt/sonatype-work/nexus3/log/
• Configuration: /opt/sonatype-work/nexus3/etc/

Upgrading Nexus

To upgrade to a newer version:

1. Backup data:

   sudo systemctl stop nexus
   sudo tar -czf nexus-backup-$(date +%Y%m%d).tar.gz /opt/sonatype-work
   

2. Download new version:

   cd /opt
   sudo wget https://download.sonatype.com/nexus/3/latest-unix.tar.gz
   sudo tar -xzf latest-unix.tar.gz
   

3. Update symbolic link:

   sudo rm nexus
   sudo ln -s nexus-<new-version> nexus
   sudo chown -R nexus:nexus /opt/nexus*
   

4. Start service:

   sudo systemctl start nexus
   

Security Considerations

Basic Hardening

• Change default ports if needed
• Enable HTTPS for production environments
• Configure proper user roles and permissions
• Regular security updates
• Monitor access logs

SSL/TLS Configuration

For production deployments, configure HTTPS by:

1. Obtaining SSL certificates
2. Configuring reverse proxy (Apache/Nginx)
3. Updating firewall rules
4. Redirecting HTTP to HTTPS

Repository Configuration

After installation, configure repositories for your specific needs:

• Proxy repositories - Mirror external repositories
• Hosted repositories - Store your artifacts
• Group repositories - Combine multiple repositories

Performance Tuning

System-Level Optimizations

# Increase file descriptor limits
echo "nexus soft nofile 65536" >> /etc/security/limits.conf
echo "nexus hard nofile 65536" >> /etc/security/limits.conf

# Configure kernel parameters
echo "vm.max_map_count=262144" >> /etc/sysctl.conf
sysctl -p

Database Configuration

For high-load environments, consider: - Migrating from H2 to PostgreSQL - Configuring database connection pooling - Regular database maintenance

Conclusion

You now have a fully functional Nexus Repository Manager installation on RHEL/CentOS. The service will automatically start on system boot and provide a centralized repository for your development artifacts.

For advanced configuration and repository-specific setup, refer to the official Sonatype Nexus Documentation.

Additional Resources

• Official Installation Guide
• System Requirements
• Repository Management
• Security Configuration