Monitoring Clock Synchronization in YugabyteDB with a Simple Bash Script

				
					#!/bin/bash

HOST=${1:-127.0.0.1}
PORT=7000
URL="http://$HOST:$PORT/tablet-server-clocks"

echo "📡 YugabyteDB Tablet Server Clocks - $HOST"
echo ""

# Fetch and flatten HTML
html=$(curl -s --connect-timeout 5 "$URL")
table=$(echo "$html" | tr '\n' ' ' | grep -oP '(?<=<h2>Tablet Servers</h2>).*?(?=</table>)')

if [[ -z "$table" ]]; then
  echo "❌ No Tablet Servers table found at $URL"
  exit 1
fi

# Grab each <tr> row
rows=$(echo "$table" | grep -oP '<tr>.*?</tr>')

# One format string for header + rows to keep columns perfectly aligned
FORMAT="%-21s %-32s %-14s %-16s %-26s %-44s %-10s %-18s %-12s %-8s\n"

# Header
printf "$FORMAT" \
  "IP_Address" "UUID" "Time_Since_HB" "Status_Uptime" \
  "Physical_Time_UTC" "Hybrid_Time_UTC" "RTT" "Cloud" "Region" "Zone"

# Use temp file to hold sortable output
tmpfile=$(mktemp)

while read -r row; do
  # Extract all <td> cells
  td_fields=$(echo "$row" | grep -oP '<td[^>]*>.*?</td>')

  # Skip header or empty rows
  [[ -z "$td_fields" ]] && continue

  # Strip HTML tags and surrounding whitespace
  mapfile -t clean_fields < <(
    echo "$td_fields" \
      | sed -E 's/<[^>]+>//g' \
      | sed 's/^[[:space:]]*//;s/[[:space:]]*$//'
  )

  # Need at least core fields:
  #   0: addr+uuid
  #   1: time since hb
  #   2: status/uptime
  #   3: physical time
  #   4: hybrid time
  #   5+: RTT (and possibly placement/cloud/region/zone)
  if [[ "${#clean_fields[@]}" -lt 6 ]]; then
    continue
  fi

  ip_uuid="${clean_fields[0]}"
  ip=$(echo "$ip_uuid"   | awk '{print $1}')
  uuid=$(echo "$ip_uuid" | awk '{print $2}')

  time_since="${clean_fields[1]}"
  status_uptime="${clean_fields[2]}"
  physical_ts="${clean_fields[3]}"
  hybrid_ts="${clean_fields[4]}"

  # Detect RTT column (allow negative values too)
  rtt_field=""
  rtt_index=-1
  for i in "${!clean_fields[@]}"; do
    if [[ "${clean_fields[$i]}" =~ ^-?[0-9.]+ms$ ]]; then
      rtt_field="${clean_fields[$i]}"
      rtt_index="$i"
      break
    fi
  done

  # Fallback if pattern didn’t match but we have at least 6 fields
  if [[ -z "$rtt_field" ]]; then
    if [[ "${#clean_fields[@]}" -ge 6 ]]; then
      rtt_index=5
      rtt_field="${clean_fields[5]}"
    else
      continue
    fi
  fi

  # ------------------------------
  # Placement / Cloud / Region / Zone handling
  # ------------------------------
  cloud="-"
  region="-"
  zone="-"

  # New-style: a single Placement column like "aws.us-east-1.us-east-1a"
  placement=""
  if (( rtt_index + 1 < ${#clean_fields[@]} )); then
    placement="${clean_fields[rtt_index+1]}"
  fi

  if [[ -n "$placement" && "$placement" == *.*.* ]]; then
    # Split "aws.us-east-1.us-east-1a" -> cloud, region, zone
    IFS='.' read -r cloud region zone <<< "$placement"
  else
    # Old-style (or unexpected): take separate columns if present
    if (( rtt_index + 1 < ${#clean_fields[@]} )); then
      cloud="${clean_fields[rtt_index+1]}"
    fi
    if (( rtt_index + 2 < ${#clean_fields[@]} )); then
      region="${clean_fields[rtt_index+2]}"
    fi
    if (( rtt_index + 3 < ${#clean_fields[@]} )); then
      zone="${clean_fields[rtt_index+3]}"
    fi
  fi

  # Numeric RTT value for sorting; treat negative RTT as N/A visually but still sortable
  rtt_ms=$(echo "$rtt_field" | sed 's/ms//')
  if [[ "$rtt_ms" == -* ]]; then
    # Dead / bogus RTT -> display N/A, push to bottom in sort
    sort_key="999999999"
    rtt_display="N/A"
  else
    sort_key="$rtt_ms"
    rtt_display="$rtt_field"
  fi

  formatted_row=$(printf "$FORMAT" \
    "$ip" "$uuid" "$time_since" "$status_uptime" \
    "$physical_ts" "$hybrid_ts" "$rtt_display" \
    "$cloud" "$region" "$zone")

  echo "$sort_key|$formatted_row" >> "$tmpfile"
done <<< "$rows"

# Sort by RTT and print
sort -n -t'|' -k1 "$tmpfile" | cut -d'|' -f2-

# Cleanup
rm -f "$tmpfile"