サーバーがシャットダウン/再起動し、"Power key pressed" というメッセージが表示される

Issue

• サーバーが自動的にシャットダウンします。
• サーバーが突然再起動しました。

• /var/log/messages ログには Power key pressed と表示されます。

  Jan 30 00:15:01 localhost systemd: Created slice User Slice of root.
  Jan 30 00:15:01 localhost systemd: Starting User Slice of root.
  Jan 30 00:15:01 localhost systemd: Started Session 6358 of user root.
  Jan 30 00:15:01 localhost systemd: Starting Session 6358 of user root.
  Jan 30 00:15:01 localhost systemd: Removed slice User Slice of root.
  Jan 30 00:15:01 localhost systemd: Stopping User Slice of root.
  Jan 30 00:18:06 localhost systemd-logind: Power key pressed.
  Jan 30 00:18:06 localhost systemd-logind: Power key pressed.
  Jan 30 00:18:06 localhost systemd-logind: Power key pressed.
  Jan 30 00:18:06 localhost systemd-logind: Power key pressed.
  Jan 30 00:18:06 localhost systemd-logind: Powering Off...
  Jan 30 00:18:06 localhost systemd-logind: Powering Off...
  Jan 30 00:18:06 localhost systemd-logind: Powering Off...
  Jan 30 00:18:06 localhost systemd-logind: Powering Off...
  Jan 30 00:18:06 localhost systemd-logind: System is powering down.
  Jan 30 00:18:06 localhost systemd-logind: System is powering down.
  Jan 30 00:18:06 localhost systemd-logind: System is powering down.
  Jan 30 00:18:06 localhost systemd-logind: System is powering down.