Linux Monitoring System

A lightweight, automated Linux server monitoring and maintenance suite written in Bash. Designed to run on any modern systemd-based Linux distribution with no external runtime dependencies beyond standard system utilities.

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Features

• Real-time terminal dashboard displaying CPU, memory, disk, and load average metrics
• Configurable threshold-based alerting with optional email notification
• Automatic detection and restart of failed critical services with retry logic
• Daily system health report generation with optional email delivery
• Log rotation with age-based deletion, size-based compression, and archive pruning
• Weekly system package upgrades and temporary file cleanup
• Security-only OS patching with support for multiple package managers
• Single-command cron job installation for full automation

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Project Structure

linux-monitoring-system/
├── config.cfg            # Central configuration file
├── monitor.sh            # Interactive real-time dashboard
├── alerts.sh             # Metric threshold checker and alerter
├── self_heal.sh          # Critical service monitor and auto-restarter
├── report.sh             # Daily system report generator
├── log_rotation.sh       # Log cleanup, compression, and pruning
├── maintenance.sh        # Weekly package updates and system cleanup
├── security_update.sh    # Security-only OS patching
├── setup_cron.sh         # Cron job installer (run once)
├── logs/                 # Runtime log files (auto-created)
└── reports/              # Generated report files (auto-created)

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Requirements

• Bash 4.0 or later
• bc — floating-point arithmetic for threshold comparisons
• systemctl — service management (systemd-based systems only)
• mail — optional, required for email alerting
• gzip or zip — optional, for log and report compression
• mpstat — optional, for extended CPU statistics in reports (provided by the sysstat package)

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Setup

1. Clone the repository

git clone https://github.com/YOUR_USERNAME/linux-monitoring-system.git
cd linux-monitoring-system

2. Edit the configuration file

nano config.cfg

At minimum, update the following:

• EMAIL_RECIPIENT — destination address for alert and report emails
• CRITICAL_SERVICES — space-separated list of services to monitor and auto-heal
• Threshold values as appropriate for your environment

3. Make all scripts executable

chmod +x *.sh

4. Install cron jobs

bash setup_cron.sh

This is a one-time operation. The script is idempotent and safe to re-run.

5. Launch the live dashboard

bash monitor.sh

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Configuration Reference

All settings are defined in config.cfg and sourced by every script at runtime.

Variable	Default	Description
CPU_WARN / CPU_CRIT	70 / 80	CPU usage alert thresholds (%)
MEMORY_WARN / MEMORY_CRIT	65 / 75	Memory usage alert thresholds (%)
DISK_WARN / DISK_CRIT	75 / 85	Disk usage alert thresholds (%)
LOAD_WARN / LOAD_CRIT	3 / 5	Load average alert thresholds
REFRESH_INTERVAL	5	Dashboard refresh interval (seconds)
EMAIL_ENABLED	true	Enable or disable email notifications
EMAIL_RECIPIENT	(configure this)	Email address for alerts and reports
CRITICAL_SERVICES	sshd nginx mysql	Services subject to auto-healing
MAX_RESTART_RETRIES	3	Maximum restart attempts per service
LOG_RETENTION_DAYS	30	Number of days before logs are deleted
LOG_MAX_SIZE_MB	50	Log file size threshold for compression (MB)
MAX_ROTATED_FILES	10	Maximum number of compressed archives to retain per log family

Log files written at runtime (inside logs/):

Variable	File	Written by
ALERT_LOG	logs/alerts.log	alerts.sh
SELF_HEAL_LOG	logs/self_heal.log	self_heal.sh
SECURITY_LOG	logs/security_update.log	security_update.sh
MAINTENANCE_LOG	logs/maintenance.log	maintenance.sh

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Cron Schedule

Installed automatically by setup_cron.sh.

Script	Schedule
alerts.sh, self_heal.sh	Every 5 minutes
report.sh	Daily at 23:59
log_rotation.sh	Daily at 00:00
maintenance.sh	Every Sunday at 02:00
security_update.sh	Every Sunday at 03:00

To remove all installed cron jobs:

crontab -l | sed "/# LINUX-MONITORING-SYSTEM-START/,/# LINUX-MONITORING-SYSTEM-END/d" | crontab -

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Supported Distributions

Distribution	Package Manager	Security Update Method
Ubuntu / Debian	apt-get	unattended-upgrade
RHEL / CentOS / Rocky / AlmaLinux	dnf / yum	--security flag
Fedora	dnf	--security flag
Arch Linux	pacman	Full system upgrade

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License

MIT License. Free to use, modify, and distribute.