Install and Configure Cacti on AlmaLinux VPS

This article provides a guide demonstrating how to install and configure Cacti on AlmaLinux VPS.

What Is Cacti?

Cacti is an open-source network monitoring and graphing tool built on top of RRDtool. It’s designed to collect, store, and visualize time-series data from networks and systems.

What Cacti Does

• Polls data from devices using SNMP or scripts (e.g., CPU load, memory usage, interface traffic)
• Stores data efficiently in round-robin databases (RRDs)
• Generates graphs to visualize trends over time (hourly, daily, weekly, etc.)
• Provides dashboards to monitor performance, bandwidth, system health

Key Features

• Web-based interface
• Custom graph templates
• Device and data source management
• User access control
• Support for SNMPv1, v2c, and v3
• Scalable with distributed polling

Common Use Cases

• Monitoring switches, routers, firewalls
• Tracking server resource usage
• Watching bandwidth consumption
• Creating historical reports on network performance

Why Use Cacti?

• Free and open-source
• Highly customizable
• Good for small to medium networks
• No vendor lock-in
• Visual and historical insights for capacity planning and troubleshooting

If you’re managing infrastructure and need insight over time, Cacti gives you the control and flexibility to track just about anything that can produce metrics.

This guide walks you through the steps to install and configure Cacti on AlmaLinux VPS from scratch.

Prerequisites

Before you start, make sure:

• You’re using AlmaLinux 8 or AlmaLinux 9
• You have sudo/root access
• Your system is up-to-date
• You have a LAMP stack installed (Apache, MariaDB, PHP)
• SELinux is either configured properly or temporarily set to permissive during setup

Install and Configure Cacti on AlmaLinux VPS

To install and configure Cacti on AlmaLinux VPS, follow the steps provided:

1. Update the System

   sudo dnf update -y

   Install essential tools:

   sudo dnf install -y wget vim bash-completion

2. Install Apache, MariaDB, and PHP

   sudo dnf install -y httpd mariadb-server php php-mysqlnd php-snmp php-gd php-xml php-mbstring php-json php-session

   Start and enable services:

   sudo systemctl enable --now httpd mariadb

   Allow HTTP/S through the firewall:

   sudo firewall-cmd --permanent --add-service=http sudo firewall-cmd --reload

3. Secure MariaDB

   Run the secure installation script:

   sudo mysql_secure_installation
   

   Follow the prompts:

   • Set a root password
   • Remove anonymous users
   • Disallow root login remotely
   • Remove test database
   • Reload privileges

4. Create Cacti Database

   mysql -u root -p

   Inside MySQL:

   CREATE DATABASE cacti; GRANT ALL PRIVILEGES ON cacti.* TO 'cactiuser'@'localhost' IDENTIFIED BY 'yourStrongPassword'; FLUSH PRIVILEGES; EXIT;

5. Install SNMP and RRDtool

   Cacti relies on SNMP for data collection:

   sudo dnf install -y net-snmp net-snmp-utils rrdtool

   Start and enable SNMP:

   sudo systemctl enable --now snmpd

6. Install Cacti

   Enable EPEL and Cacti packages:

   sudo dnf install -y epel-release sudo dnf install -y cacti

7. Import Default Database

   mysql -u cactiuser -p cacti < /usr/share/doc/cacti/cacti.sql

8. Configure Cacti Settings

   Edit /etc/cacti/db.php:

   $database_type = "mysql"; $database_default = "cacti"; $database_hostname = "localhost"; $database_username = "cactiuser"; $database_password = "yourStrongPassword";

   Ensure Apache has access:

   sudo chown -R apache:apache /var/lib/cacti/rra /var/lib/cacti/log

9. Configure Apache for Cacti

   Edit /etc/httpd/conf.d/cacti.conf:

   <Directory /usr/share/cacti/> Require all granted </Directory>

   Restart Apache:

   sudo systemctl restart httpd

10. Configure Cron for Polling

    Enable polling every 5 minutes:

    sudo vi /etc/cron.d/cacti

    Uncomment or add the line:

    */5 * * * * apache /usr/bin/php /usr/share/cacti/poller.php > /dev/null 2>&1

11. SELinux Configuration

    If SELinux is enforcing, run:

    sudo setsebool -P httpd_can_connect_db 1 sudo chcon -R -t httpd_sys_rw_content_t /var/lib/cacti/rra /var/lib/cacti/log

    Or temporarily set to permissive:

    sudo setenforce 0

12. Web Installer

    Navigate to:

    http://your-server-ip/cacti
    

    Follow the web-based installation wizard:

    • Verify pre-install checks
    • Confirm database connection
    • Set admin credentials
    • Import templates

13. Final Tweaks

    Log in using the default credentials:

    • Username: admin
    • Password: admin (you’ll be prompted to change it)

    Once inside:

    • Add devices for monitoring
    • Configure SNMP community strings
    • Review graphs under “Graph View”

14. Secure Cacti with HTTPS via Let’s Encrypt

    Using HTTPS ensures encrypted traffic between users and your Cacti interface. We’ll use Certbot with Apache to install a free TLS certificate from Let’s Encrypt.

    1. Install Certbot and Apache plugin

       sudo dnf install -y certbot python3-certbot-apache

    2. Obtain and Install the SSL Certificate

       Replace yourdomain.com with your actual domain name:

       sudo certbot --apache -d yourdomain.com
       

       Follow the prompts:

       • Choose whether to redirect HTTP to HTTPS (recommended: select the redirect option)
       • Certbot will automatically configure Apache for SSL

    3. Test SSL Configuration

       Visit:

       https://yourdomain.com/cacti

       You should see the Cacti login page with a secure padlock in the browser.

    4. Automate SSL Renewal

       Let’s Encrypt certificates expire every 90 days. Add a cron job or systemd timer to handle this automatically:

       sudo systemctl enable --now certbot-renew.timer

       You can also test the renewal process manually:

       sudo certbot renew --dry-run

    By securing Cacti with HTTPS, you ensure that sensitive monitoring data — like device configurations, login credentials, and performance graphs — are encrypted in transit. This step is critical for security, especially if you’re accessing your dashboard over the public internet.

15. Troubleshooting Tips

    • Check logs in /var/log/httpd/ for web errors.
    • Use php -m to ensure required PHP modules are installed.
    • Ensure timezones match (/etc/php.ini, /etc/cacti/global.php).
    • Cacti graphs not showing? Check /usr/share/cacti/poller.php output manually.

    sudo -u apache php /usr/share/cacti/poller.php
    

Conclusion

You now know how to install and configure Cacti on AlmaLinux VPS. This setup provides a solid foundation for network monitoring and performance graphing. With SNMP in place, you can start graphing metrics for routers, switches, servers, and any SNMP-enabled device.

For production environments, secure your installation further:

• Stronger MySQL and web access policies
• SELinux set back to enforcing with proper contexts