localhost:9090

Port 9090 is commonly used by Prometheus (monitoring toolkit) and Cockpit (Linux web console). Prometheus collects metrics from your applications while Cockpit provides a web-based interface to manage Linux servers.

What Uses Port 9090?

Prometheus Setup

Prometheus is the leading open-source monitoring solution for cloud-native environments.

# Docker (quickest)
docker run -d -p 9090:9090 prom/prometheus

# Download binary
wget https://github.com/prometheus/prometheus/releases/latest
tar xvfz prometheus-*.tar.gz
cd prometheus-*
./prometheus --config.file=prometheus.yml

Prometheus UI Endpoints

Basic PromQL Queries

# CPU usage rate
rate(process_cpu_seconds_total[5m])

# Memory usage
process_resident_memory_bytes

# HTTP request rate
rate(http_requests_total[5m])

# Error rate (5xx responses)
rate(http_requests_total{status=~"5.."}[5m])

# Up/down status
up{job="your-service"}

Cockpit Setup (Linux)

Cockpit is a web-based graphical interface for managing Linux servers.

# Install on Ubuntu/Debian
sudo apt install cockpit

# Install on RHEL/CentOS
sudo dnf install cockpit
sudo systemctl enable --now cockpit.socket

# Access at
https://localhost:9090

Cockpit Features

• System Overview — CPU, memory, disk usage
• Logs — View system and application logs
• Storage — Manage disks and partitions
• Networking — Configure interfaces, firewall
• Containers — Manage Podman/Docker
• Terminal — Web-based terminal access

Port 9090 Not Working?