#!/bin/bash
# Nagios plugin to check iowait on Linux

if ! command -v iostat &>/dev/null; then
  echo "iostat not found! Please install sysstat:"
  echo "sudo apt install sysstat"
  exit 1
fi

#!/bin/bash

# Nagios plugin to check iowait on Linux

# Define usage function
function usage {
  echo "Usage: $0 [-w <warning threshold>] [-c <critical threshold>] [-a <average seconds>]"
  echo "  -w: Warning threshold for iowait percentage (default: 50)"
  echo "  -c: Critical threshold for iowait percentage (default: 75)"
  echo "  -a: Number of seconds to average iowait (default: 5)"
  exit 3
}

# Parse command line arguments
while getopts "w:c:a:" opt; do
  case $opt in
  w) WARNING_THRESHOLD=$OPTARG ;;
  c) CRITICAL_THRESHOLD=$OPTARG ;;
  a) AVERAGE_SECONDS=$OPTARG ;;
  \?)
    echo "Invalid option: -$OPTARG" >&2
    usage
    ;;
  :)
    echo "Option -$OPTARG requires an argument." >&2
    usage
    ;;
  esac
done

# Set default warning and critical thresholds if not provided
WARNING_THRESHOLD=${WARNING_THRESHOLD:-50}
CRITICAL_THRESHOLD=${CRITICAL_THRESHOLD:-75}
AVERAGE_SECONDS=${AVERAGE_SECONDS:-5}

# Get current iowait percentage and number of processes
IOWAIT=$(iostat -c $AVERAGE_SECONDS 2 | awk '/^ /{print $4}' | tail -n 1)
PROCESSES=$(ps -A --no-headers | wc -l)

# Check if iowait percentage is above critical threshold
if (($(echo "$IOWAIT > $CRITICAL_THRESHOLD" | bc -l))); then
  echo "CRITICAL - iowait percentage is $IOWAIT% | iowait=$IOWAIT%;$WARNING_THRESHOLD;$CRITICAL_THRESHOLD;0;100"
  exit 2
fi

# Check if iowait percentage is above warning threshold
if (($(echo "$IOWAIT > $WARNING_THRESHOLD" | bc -l))); then
  echo "WARNING - iowait percentage is $IOWAIT% | iowait=$IOWAIT%;$WARNING_THRESHOLD;$CRITICAL_THRESHOLD;0;100"
  exit 1
fi

# If iowait percentage is below warning threshold, exit with OK status
echo "OK - iowait percentage is $IOWAIT% | iowait=$IOWAIT%;$WARNING_THRESHOLD;$CRITICAL_THRESHOLD;0;100"
exit 0