File: //usr/libexec/kcare/migrations/migrate-cron-hour-randomize.sh
#!/bin/bash
set -eu -o pipefail
# Randomize auto-update hour to spread load across ePortal.
# Instead of all agents checking at */4 (0,4,8,12,16,20), randomly pick
# one of four hour-offset schedules to distribute requests evenly.
KCARE_CRONFILE=/etc/cron.d/kcare-cron
if [[ ! -f "$KCARE_CRONFILE" ]]; then
exit 0
fi
if ! grep -qE '^[0-9]+[[:space:]]+\*/4[[:space:]]' "$KCARE_CRONFILE"; then
exit 0
fi
case $(( RANDOM % 4 )) in
0) HOURS='0,4,8,12,16,20' ;;
1) HOURS='1,5,9,13,17,21' ;;
2) HOURS='2,6,10,14,18,22' ;;
3) HOURS='3,7,11,15,19,23' ;;
esac
sed -Ei 's/^([0-9]+[[:space:]]+)\*\/4([[:space:]])/\1'"$HOURS"'\2/' "$KCARE_CRONFILE"