How to Install ntopng with Redis on AlmaLinux 9 Using Docker

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Introduction

This guide explains how to install and run ntopng Community Edition on AlmaLinux 9 using Docker, with Redis as the backend database.

ntopng is a powerful network traffic monitoring and analysis tool that provides real-time visibility into network usage, protocols, and hosts through a modern web interface.

Using Docker provides:

Clean and isolated deployment
Easy upgrades and maintenance
Automatic restart after system reboot
No dependency conflicts with the host OS

This guide assumes:

You are logged in as root
AlmaLinux 9 is installed
The system has Internet access
The primary network interface is eth0

Architecture Overview

Docker: Container runtime
Redis: Backend database for ntopng
ntopng: Network traffic analyzer
eth0: Physical network interface being monitored
Port 3000: ntopng Web UI

Step 1: Update the System

Explanation:

Ensures the system is fully up to date
Installs required utilities for repository management

Step 2: Install Docker Engine

2.1 Add the Docker Repository

Explanation:

AlmaLinux is RHEL-compatible, so the CentOS Docker repository is used

2.2 Install Docker Components

Explanation:

docker-ce: Docker Engine
docker-ce-cli: Docker CLI
containerd.io: Container runtime
docker-compose-plugin: Optional multi-container support

2.3 Enable and Start Docker

systemctl enable --now docker
systemctl status docker

Docker should display:

Step 3: Identify the Network Interface

ntopng must capture traffic from the physical network interface.

ip link show

Example output:

Step 4: Run Redis Container

Redis must be running before ntopng starts.

docker run -d \
  --name redis \
  --restart always \
  -p 6379:6379 \
  redis:alpine

Explanation of Options

-d: Run container in the background
–name redis: Assign a container name
–restart always: Automatically restart on failure or reboot
-p 6379:6379: Expose Redis service
redis:alpine: Lightweight Redis image

Verify Redis

docker exec -it redis redis-cli ping

Expected output:

Step 5: Run ntopng Container

docker run -d \
  --name ntopng \
  --net=host \
  --privileged \
  --restart always \
  ntop/ntopng:latest \
  -i eth0 \
  -r 127.0.0.1:6379 \
  -w 3000 \
  --community

Explanation of Options

Option	Description
–net=host	Allows direct access to host network interfaces
–privileged	Required for packet capture
–restart always	Ensures service survives reboots
-i eth0	Interface being monitored
-r 127.0.0.1:6379	Redis backend location
-w 3000	Web UI port
–community	Community Edition mode

Step 6: Verify ntopng Status

docker ps
docker logs ntopng

Healthy logs include:

ntopng started
Listening on port 3000
No Redis connection errors

Step 7: Access ntopng Web Interface

Open a browser and navigate to:

http://<SERVER_IP>:3000

Default Credentials

Username: admin
Password: admin

You will be prompted to change the password on first login.

Common Management Commands

docker restart ntopng
docker logs -f ntopng

Conclusion

You have successfully deployed ntopng Community Edition with Redis on AlmaLinux 9 using Docker.

This configuration provides:

Real-time network visibility
A stable Redis backend
Automatic service recovery after reboot
A clean, containerized deployment model

This setup is suitable for labs, VPS environments, and production monitoring systems.
For advanced usage, consider Docker Compose, persistent Redis storage, or multi-interface monitoring.