Add server health monitoring script with disk, CPU, and memory checks

README_SERVER_HEALTH.md

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+# Server Health Monitoring Script
+
+## Overview
+This script monitors the health of a Linux server by checking disk space, CPU usage, and memory usage against a 60% threshold.
+
+## Usage
+
+### Basic Usage
+```bash
+./server_health_check.sh
+```
+Returns either `healthy` or `unhealthy` based on current system metrics.
+
+### Detailed Explanation
+```bash
+./server_health_check.sh explain
+```
+Returns the health status along with:
+- Current metrics for disk, CPU, and memory usage
+- Threshold value (60%)
+- Detailed reasons if the server is unhealthy
+
+## Health Criteria
+- **Healthy**: All metrics (disk, CPU, memory) are below 60%
+- **Unhealthy**: One or more metrics exceed 60%
+
+## Exit Codes
+- `0`: Server is healthy
+- `1`: Server is unhealthy
+
+## Example Output
+
+### Without explain argument:
+```
+healthy
+```
+
+### With explain argument:
+```
+Server Status: unhealthy
+
+Current Metrics:
+  - Disk usage: 76%
+  - CPU usage: 15%
+  - Memory usage: 45%
+
+Threshold: 60%
+
+Reasons for unhealthy status:
+  - Disk usage is 76% (threshold: 60%)
+```
+
+## Requirements
+- Linux operating system
+- Standard utilities: `df`, `free`, `top`, `awk`, `grep`, `sed`

server_health_check.sh

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+#!/bin/bash
+
+# Server Health Monitoring Script
+# Checks disk space, CPU usage, and memory usage
+# Returns "healthy" if all metrics are below 60%, "unhealthy" otherwise
+# Usage: ./server_health_check.sh [explain]
+
+THRESHOLD=60
+
+# Function to get disk usage percentage (highest mount point)
+get_disk_usage() {
+    df -h | grep -vE '^Filesystem|tmpfs|cdrom|loop' | awk '{ print $5 }' | sed 's/%//g' | sort -rn | head -1
+}
+
+# Function to get CPU usage percentage
+get_cpu_usage() {
+    # Using top to get CPU usage (100 - idle percentage)
+    # We'll sample for 2 seconds to get an accurate reading
+    top -bn2 -d 1 | grep "Cpu(s)" | tail -1 | awk '{print $2}' | sed 's/%us,//g' | awk '{printf "%.0f", $1}'
+}
+
+# Function to get memory usage percentage
+get_memory_usage() {
+    free | grep Mem | awk '{printf "%.0f", ($3/$2) * 100.0}'
+}
+
+# Get current metrics
+DISK_USAGE=$(get_disk_usage)
+CPU_USAGE=$(get_cpu_usage)
+MEMORY_USAGE=$(get_memory_usage)
+
+# Check if any metric exceeds threshold
+UNHEALTHY=0
+REASONS=()
+
+if [ "$DISK_USAGE" -ge "$THRESHOLD" ]; then
+    UNHEALTHY=1
+    REASONS+=("Disk usage is ${DISK_USAGE}% (threshold: ${THRESHOLD}%)")
+fi
+
+if [ "$CPU_USAGE" -ge "$THRESHOLD" ]; then
+    UNHEALTHY=1
+    REASONS+=("CPU usage is ${CPU_USAGE}% (threshold: ${THRESHOLD}%)")
+fi
+
+if [ "$MEMORY_USAGE" -ge "$THRESHOLD" ]; then
+    UNHEALTHY=1
+    REASONS+=("Memory usage is ${MEMORY_USAGE}% (threshold: ${THRESHOLD}%)")
+fi
+
+# Determine health status
+if [ "$UNHEALTHY" -eq 1 ]; then
+    STATUS="unhealthy"
+else
+    STATUS="healthy"
+fi
+
+# Output based on argument
+if [ "$1" == "explain" ]; then
+    echo "Server Status: $STATUS"
+    echo ""
+    echo "Current Metrics:"
+    echo "  - Disk usage: ${DISK_USAGE}%"
+    echo "  - CPU usage: ${CPU_USAGE}%"
+    echo "  - Memory usage: ${MEMORY_USAGE}%"
+    echo ""
+    echo "Threshold: ${THRESHOLD}%"
+    echo ""
+
+    if [ "$UNHEALTHY" -eq 1 ]; then
+        echo "Reasons for unhealthy status:"
+        for reason in "${REASONS[@]}"; do
+            echo "  - $reason"
+        done
+    else
+        echo "All metrics are below the ${THRESHOLD}% threshold."
+    fi
+else
+    echo "$STATUS"
+fi
+
+# Exit with appropriate code
+exit $UNHEALTHY