Monitoring

Monitoring Tools

Complete guide to monitoring your VPS with Prometheus, Grafana, Nagios, and other tools. Learn system monitoring, alerting, and performance tracking.

Prerequisites

Root or sudo access to your VPS
Basic understanding of Linux system administration
Email server configured for alerts (optional)
Sufficient system resources for monitoring tools
Understanding of your application stack

Monitoring Fundamentals

Effective monitoring is crucial for maintaining server health, performance, and availability. A good monitoring system helps you detect issues before they become critical problems.

Key Monitoring Areas:

System Resources - CPU, memory, disk, network
Application Performance - Response times, error rates
Security Events - Failed logins, suspicious activity
Service Availability - Uptime, service status
Logs and Events - Application and system logs

# Basic system monitoring commands
# CPU usage
top
htop
mpstat 1

# Memory usage
free -h
vmstat 1
cat /proc/meminfo

# Disk usage
df -h
du -sh /var/log/*
iostat -x 1

# Network monitoring
ifconfig
ip addr
netstat -tlnp
ss -tlnp

Prometheus + Grafana Stack

The Prometheus and Grafana combination is one of the most popular open-source monitoring solutions. Prometheus handles metrics collection and storage, while Grafana provides beautiful dashboards and visualization.

Architecture Overview:

Prometheus - Metrics collection and storage
Grafana - Dashboard and visualization
Node Exporter - System metrics exporter
Alertmanager - Alert handling and routing

# Install Prometheus
sudo apt update
sudo apt install prometheus prometheus-node-exporter -y

# Start and enable services
sudo systemctl enable prometheus
sudo systemctl enable prometheus-node-exporter
sudo systemctl start prometheus
sudo systemctl start prometheus-node-exporter

# Check status
sudo systemctl status prometheus
curl http://localhost:9090

# Install Grafana
sudo apt install software-properties-common -y
sudo add-apt-repository "deb https://packages.grafana.com/oss/deb stable main"
wget -q -O - https://packages.grafana.com/gpg.key | sudo apt-key add -
sudo apt update
sudo apt install grafana -y

# Start Grafana
sudo systemctl enable grafana-server
sudo systemctl start grafana-server

# Access Grafana at http://your-server:3000
# Default credentials: admin/admin

Nagios Monitoring

Nagios is a powerful monitoring system that provides comprehensive monitoring of hosts, services, and networks. It's highly configurable and supports extensive plugin ecosystem.

Nagios Features:

Host and service monitoring
Alerting and notifications
Performance data collection
Web interface for status viewing
Plugin architecture for extensibility

# Install Nagios
sudo apt update
sudo apt install nagios4 nagios-plugins -y

# Install additional plugins
sudo apt install nagios-plugins-contrib -y

# Configure Nagios admin password
sudo htpasswd -c /etc/nagios4/htpasswd.users nagiosadmin

# Add your server to monitoring
sudo nano /etc/nagios4/conf.d/localhost_nagios2.cfg

# Basic host definition example:
define host {
    use                     linux-server
    host_name               your-server
    alias                   Your VPS Server
    address                 127.0.0.1
}

# Restart Nagios
sudo systemctl restart nagios4

# Access web interface: http://your-server/nagios4
# Username: nagiosadmin

System Monitoring with htop & iotop

Command-line monitoring tools provide real-time system information and are essential for troubleshooting and performance analysis.

Essential CLI Tools:

htop - Interactive process viewer
iotop - I/O monitoring
nload - Network bandwidth monitoring
dstat - System resource statistics
glances - System monitoring overview

# Install monitoring tools
sudo apt install htop iotop nload dstat glances -y

# htop - Interactive process viewer
htop

# iotop - I/O monitoring
sudo iotop

# nload - Network monitoring
nload

# dstat - Comprehensive system stats
dstat -cdngy 1

# glances - System overview
glances

# Monitor specific processes
ps aux | grep apache
pgrep -f apache | xargs ps -p

# Monitor system logs in real-time
tail -f /var/log/syslog
tail -f /var/log/auth.log

Log Monitoring & Analysis

Log files contain valuable information about system events, errors, and security incidents. Effective log monitoring helps identify issues and security threats.

Log Monitoring Tools:

rsyslog - System logging daemon
logrotate - Log rotation utility
journalctl - Systemd journal viewer
fail2ban - Log-based intrusion prevention
ELK Stack - Log aggregation and analysis

# View system logs
sudo journalctl -u apache2 -f  # Follow Apache logs
sudo journalctl -u mysql -f   # Follow MySQL logs
sudo journalctl --since "1 hour ago"

# Monitor specific log files
tail -f /var/log/apache2/access.log
tail -f /var/log/apache2/error.log

# Search logs for specific patterns
grep "error" /var/log/apache2/error.log
grep "404" /var/log/apache2/access.log

# Configure logrotate
sudo nano /etc/logrotate.d/apache2

# Example logrotate configuration:
/var/log/apache2/*.log {
    daily
    missingok
    rotate 52
    compress
    delaycompress
    notifempty
    create 644 root root
    postrotate
        systemctl reload apache2
    endscript
}

# Monitor disk space used by logs
du -sh /var/log/* | sort -hr | head -10

Alerting & Notification Setup

Alerts notify you when something goes wrong with your system. Setting up proper alerting ensures you respond quickly to critical issues.

Alerting Strategies:

Email notifications
SMS alerts for critical issues
Slack/Discord integrations
PagerDuty/opsgenie for on-call
Custom webhooks

# Configure email alerts
sudo apt install mailutils -y

# Test email functionality
echo "Test message" | mail -s "Test Subject" your-email@example.com

# Configure SMTP for alerts
sudo nano /etc/ssmtp/ssmtp.conf

# Example ssmtp configuration:
# root=your-email@example.com
# mailhub=smtp.gmail.com:587
# AuthUser=your-email@gmail.com
# AuthPass=your-app-password
# UseTLS=YES
# UseSTARTTLS=YES

# Create alert script
sudo nano /usr/local/bin/alert.sh

#!/bin/bash
SUBJECT="$1"
MESSAGE="$2"
TO_EMAIL="admin@example.com"

echo "$MESSAGE" | mail -s "$SUBJECT" $TO_EMAIL

# Make it executable
sudo chmod +x /usr/local/bin/alert.sh

# Test the alert system
/usr/local/bin/alert.sh "Test Alert" "This is a test alert from your server"

Performance Monitoring

Performance monitoring helps identify bottlenecks and optimize system resources. Regular performance analysis ensures optimal server operation.

Performance Metrics:

CPU utilization and load averages
Memory usage and swap activity
Disk I/O and storage performance
Network throughput and latency
Application response times

# Performance monitoring commands
# CPU performance
vmstat 1
mpstat -P ALL 1
sar -u 1

# Memory analysis
free -m
cat /proc/meminfo
ps aux --sort=-%mem | head -10

# Disk performance
iostat -x 1
fio --name=readtest --rw=randread --bs=4k --numjobs=4 --runtime=10

# Network performance
sar -n DEV 1
iperf3 -s  # Server mode
iperf3 -c server-ip  # Client mode

# Application performance
# Apache/Nginx
curl -w "@curl-format.txt" -o /dev/null -s http://localhost/

# MySQL
mysql -e "SHOW PROCESSLIST;"
mysql -e "SHOW ENGINE INNODB STATUS;"

# PHP performance
php -r "echo 'PHP version: ' . phpversion() . PHP_EOL;"

Contents

Related Docs

Performance Optimization

Optimize your system based on monitoring data

Security Hardening

Monitor security events and threats

Backup & Restore

Monitor backup processes and storage

Need Help?

Can't find what you're looking for? Our support team is here to help.

# Basic system monitoring commands # CPU usage top htop mpstat 1 # Memory usage free -h vmstat 1 cat /proc/meminfo # Disk usage df -h du -sh /var/log/* iostat -x 1 # Network monitoring ifconfig ip addr netstat -tlnp ss -tlnp

# Install Prometheus sudo apt update sudo apt install prometheus prometheus-node-exporter -y # Start and enable services sudo systemctl enable prometheus sudo systemctl enable prometheus-node-exporter sudo systemctl start prometheus sudo systemctl start prometheus-node-exporter # Check status sudo systemctl status prometheus curl http://localhost:9090 # Install Grafana sudo apt install software-properties-common -y sudo add-apt-repository "deb https://packages.grafana.com/oss/deb stable main" wget -q -O - https://packages.grafana.com/gpg.key | sudo apt-key add - sudo apt update sudo apt install grafana -y # Start Grafana sudo systemctl enable grafana-server sudo systemctl start grafana-server # Access Grafana at http://your-server:3000 # Default credentials: admin/admin

# Install Nagios sudo apt update sudo apt install nagios4 nagios-plugins -y # Install additional plugins sudo apt install nagios-plugins-contrib -y # Configure Nagios admin password sudo htpasswd -c /etc/nagios4/htpasswd.users nagiosadmin # Add your server to monitoring sudo nano /etc/nagios4/conf.d/localhost_nagios2.cfg # Basic host definition example: define host { use linux-server host_name your-server alias Your VPS Server address 127.0.0.1 } # Restart Nagios sudo systemctl restart nagios4 # Access web interface: http://your-server/nagios4 # Username: nagiosadmin

# Install monitoring tools sudo apt install htop iotop nload dstat glances -y # htop - Interactive process viewer htop # iotop - I/O monitoring sudo iotop # nload - Network monitoring nload # dstat - Comprehensive system stats dstat -cdngy 1 # glances - System overview glances # Monitor specific processes ps aux | grep apache pgrep -f apache | xargs ps -p # Monitor system logs in real-time tail -f /var/log/syslog tail -f /var/log/auth.log

# View system logs sudo journalctl -u apache2 -f # Follow Apache logs sudo journalctl -u mysql -f # Follow MySQL logs sudo journalctl --since "1 hour ago" # Monitor specific log files tail -f /var/log/apache2/access.log tail -f /var/log/apache2/error.log # Search logs for specific patterns grep "error" /var/log/apache2/error.log grep "404" /var/log/apache2/access.log # Configure logrotate sudo nano /etc/logrotate.d/apache2 # Example logrotate configuration: /var/log/apache2/*.log { daily missingok rotate 52 compress delaycompress notifempty create 644 root root postrotate systemctl reload apache2 endscript } # Monitor disk space used by logs du -sh /var/log/* | sort -hr | head -10

# Configure email alerts sudo apt install mailutils -y # Test email functionality echo "Test message" | mail -s "Test Subject" your-email@example.com # Configure SMTP for alerts sudo nano /etc/ssmtp/ssmtp.conf # Example ssmtp configuration: # root=your-email@example.com # mailhub=smtp.gmail.com:587 # AuthUser=your-email@gmail.com # AuthPass=your-app-password # UseTLS=YES # UseSTARTTLS=YES # Create alert script sudo nano /usr/local/bin/alert.sh #!/bin/bash SUBJECT="$1" MESSAGE="$2" TO_EMAIL="admin@example.com" echo "$MESSAGE" | mail -s "$SUBJECT" $TO_EMAIL # Make it executable sudo chmod +x /usr/local/bin/alert.sh # Test the alert system /usr/local/bin/alert.sh "Test Alert" "This is a test alert from your server"

# Performance monitoring commands # CPU performance vmstat 1 mpstat -P ALL 1 sar -u 1 # Memory analysis free -m cat /proc/meminfo ps aux --sort=-%mem | head -10 # Disk performance iostat -x 1 fio --name=readtest --rw=randread --bs=4k --numjobs=4 --runtime=10 # Network performance sar -n DEV 1 iperf3 -s # Server mode iperf3 -c server-ip # Client mode # Application performance # Apache/Nginx curl -w "@curl-format.txt" -o /dev/null -s http://localhost/ # MySQL mysql -e "SHOW PROCESSLIST;" mysql -e "SHOW ENGINE INNODB STATUS;" # PHP performance php -r "echo 'PHP version: ' . phpversion() . PHP_EOL;"