服务器是Cent OS。
httpd工作正常，这就是我关闭整个服务器拍摄快照的原因。重新启动后，httpd不再工作，这是来自jorunalctl的错误：
-- Unit httpd.service has begun starting up.
Mar 16 12:47:49 ragnar01.novalocal httpd[2350]: httpd (pid 2322) already running
Mar 16 12:47:49 ragnar01.novalocal kill[2351]: kill: cannot find process ""
Mar 16 12:47:49 ragnar01.novalocal systemd[1]: httpd.service: control process exited, code=exited status=1
Mar 16 12:47:49 ragnar01.novalocal systemd[1]: Failed to start The Apache HTTP Server.
-- Subject: Unit httpd.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit httpd.service has failed.
--
-- The result is failed.
Mar 16 12:47:49 ragnar01.novalocal systemd[1]: Unit httpd.service entered failed state.
Mar 16 12:47:49 ragnar01.novalocal systemd[1]: httpd.service failed.
Mar 16 12:47:49 ragnar01.novalocal polkitd[779]: Unregistered Authentication Agent for unix-process:2335:24998 (system bus name :1.13, object path /org/freedesktop/PolicyKit1/AuthenticationAgent, locale en_US.UTF-8) (disconnected from bus)
Mar 16 12:48:00 ragnar01.novalocal sshd[2332]: Connection closed by 123.183.209.139 [preauth]
我很高兴再次启动它。