很简单的一个问题，但过程比较难绷，所以特此记录
为了能方便的既跑虚拟机，又跑Docker容器，我经常使用Fedora Server来作为宿主系统，配合红帽官方的Cockpit面板进行管理，其对虚拟机（基于libvirt/qemu/kvm）和容器（官方只支持Podman）的支持尚可。
但其在关机时虚拟机会直接被强制停止，并不安全。我们希望在直接对宿主机进行关机或重启时，其能够像PVE、EXSi等虚拟化系统一样发起并等待虚拟机的安全关机。
首先这个功能libvirt是提供了的，由libvirt-guests.service实现，但不知为何在Fedora并没有被默认启用。
进一步的，我们发现其配置文件/etc/sysconfig/libvirt-guests从某个版本起被移除了（你还能搜到关于这件事的相关讨论，暴躁用户 vs 倔强maintainer），更不方便我们配置了，因此首先恢复其内容：
# URIs to check for running guests
# example: URIS='default xen:/// vbox+tcp://host/system lxc:///'
#URIS=default
# action taken on host boot
# - start all guests which were running on shutdown are started on boot
# regardless on their autostart settings
# - ignore libvirt-guests init script won't start any guest on boot, however,
# guests marked as autostart will still be automatically started by
# libvirtd
#ON_BOOT=start
# Number of seconds to wait between each guest start. Set to 0 to allow
# parallel startup.
#START_DELAY=0
# action taken on host shutdown
# - suspend all running guests are suspended using virsh managedsave
# - shutdown all running guests are asked to shutdown. Please be careful with
# this settings since there is no way to distinguish between a
# guest which is stuck or ignores shutdown requests and a guest
# which just needs a long time to shutdown. When setting
# ON_SHUTDOWN=shutdown, you must also set SHUTDOWN_TIMEOUT to a
# value suitable for your guests.
ON_SHUTDOWN=shutdown
# If set to non-zero, shutdown will suspend guests concurrently. Number of
# guests on shutdown at any time will not exceed number set in this variable.
#PARALLEL_SHUTDOWN=0
# Number of seconds we're willing to wait for a guest to shut down. If parallel
# shutdown is enabled, this timeout applies as a timeout for shutting down all
# guests on a single URI defined in the variable URIS. If this is 0, then there
# is no time out (use with caution, as guests might not respond to a shutdown
# request). The default value is 300 seconds (5 minutes).
#SHUTDOWN_TIMEOUT=300
# If non-zero, try to bypass the file system cache when saving and
# restoring guests, even though this may give slower operation for
# some file systems.
#BYPASS_CACHE=0注意我这里设置的是ON_SHUTDOWN=shutdown，因为对于有PCIe设备直通的虚拟机suspend可能无法使用。
然后启用libvirt-guests.service服务：
sudo systemctl enable --now libvirt-guests然后在虚拟机关机时（或libvirt-guests服务关闭时）正在运行的虚拟机应当能正常关机，并且这些虚拟机会在宿主机下次启动时自动启动（恢复状态）。
这里不得不吐槽一下红帽经常搞一些breaking change，之前升级就被Network UPS Tools (NUT)的服务配置坑过一次
