Clean up puppet-agent services left by a SYSV init script after upgrade to SystemD

reaper.sh

#!/bin/bash

# A reaper script that scans the PIDs of services belonging to the puppet-agent
# package. When invoked with --check, the script exits non-zero if any such
# PIDs are found and also executes `systemctl daemon-reload` if needed. When
# invoked with --clean, the script kills any such PIDs and re-starts the
# affected services.

PUPPET_SERVICES=(puppet pxp-agent mcollective)
PARENT=$PPID

ls_deleted() {
  local pid exe

  pgrep "${1?}" | while IFS= read -r pid; do
    if [[ $pid -eq $PARENT ]]; then
      # This script will be invoked from a puppet worker process that may be
      # running from a deleted ruby executable. Don't kill our parent.
      continue
    fi

    exe=$(readlink "/proc/${pid}/exe")

    if [[ "${exe}" = *"deleted"* ]]; then
      printf '%s\n' "${pid}"
    fi
  done
}

check() {
  local systemctl_result zombie_services=() \
        systemctl_failed='Failed to get properties: Access denied'

  systemctl_result=$(systemctl status "${PUPPET_SERVICES[@]}" 2>&1)

  if [[ "${systemctl_result}" = *"${systemctl_failed}"* ]]; then
    logger -s 'Executing systemctl-daemon reload to clear SELinux denial.'
    # Make systemd aware of new el-7 unit files.
    systemctl daemon-reload
  fi

  for service in "${PUPPET_SERVICES[@]}"; do
    zombie_services+=($(ls_deleted "${service}"))
  done

  if [[ "${#zombie_services[@]}" -gt 0 ]]; then
    logger -s "Found PIDs from removed el-6 package: ${zombie_services[*]}"
    exit 1
  else
    exit 0
  fi
}

clean() {
  local zombie_services=()

  for service in "${PUPPET_SERVICES[@]}"; do
    zombie_services=($(ls_deleted "${service}"))

    if [[ "${#zombie_services[@]}" -gt 0 ]]; then
      logger -s "Sending SIGTERM to ${service} PIDs from obsolete el-6 package: ${zombie_services[*]}"
      kill -TERM "${zombie_services[@]}"

      logger -s "Re-starting ${service}."
      systemctl restart "${service}"
    fi
  done
}

case "${1}" in
  --check)
    check
    ;;
  --clean)
    clean
    ;;
  *)
    printf 'This script must be called with a --check or --clean flag.\n'
    exit 1
    ;;
esac