Сеть — алерт по packet-loss до upstream (через mtr)

#!/usr/bin/env bash
# /etc/cron.d/packet-loss
# */5 * * * * root /opt/packet-loss.sh

TARGET=${TARGET:-db.internal}
THRESH_PCT=${THRESH_PCT:-3}           # alert above 3 % loss

# mtr -r = report mode, -c 100 = 100 packets, -n = numeric only
LOSS=$(mtr -r -c 100 -n "$TARGET" \
  | awk 'END {gsub(/%/,"",$3); print $3+0}')

if [ "${LOSS:-0}" -gt "$THRESH_PCT" ]; then
  curl -fsS "$HEARTBEAT_URL" --data "loss_pct=$LOSS,target=$TARGET"
  exit 2
fi
echo "OK (loss=${LOSS}%)"