任何人都可以在这里帮忙我有一个新的 Centos 7 安装我试图在安装后安装 qemu-guest-agent 我试图启动它，但出现以下错误：
[root@localhost ~]# systemctl start qemu-guest-agent
A dependency job for qemu-guest-agent.service failed. See 'journalctl -xe' for details.
这是journalctl -xe :
--
-- Unit dev-virtio\x2dports-org.qemu.guest_agent.0.device has failed.
--
-- The result is timeout.
May 03 14:06:57 localhost.localdomain systemd[1]: Dependency failed for QEMU Guest Agent.
-- Subject: Unit qemu-guest-agent.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit qemu-guest-agent.service has failed.
--
-- The result is dependency.
May 03 14:06:57 localhost.localdomain systemd[1]: Job qemu-guest-agent.service/start failed with result 'dependency'.
May 03 14:06:57 localhost.localdomain systemd[1]: Startup finished in 1.474s (kernel) + 4.095s (initrd) + 2min 5.416s (userspace) = 2min 10.985s.
-- Subject: System start-up is now complete
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- All system services necessary queued for starting at boot have been
-- successfully started. Note that this does not mean that the machine is
-- now idle as services might still be busy with completing start-up.
--
-- Kernel start-up required 1474322 microseconds.
--
-- Initial RAM disk start-up required 4095564 microseconds.
--
-- Userspace start-up required 125416032 microseconds.
May 03 14:06:57 localhost.localdomain systemd[1]: Job dev-virtio\x2dports-org.qemu.guest_agent.0.device/start failed with result 'timeout'.
May 03 14:06:57 localhost.localdomain polkitd[624]: Unregistered Authentication Agent for unix-process:7214:4088 (system bus name :1.22, object path /org/freedesktop/PolicyKit1/Authenticatio
May 03 14:07:59 localhost.localdomain sudo[8162]: root : TTY=pts/0 ; PWD=/root ; USER=root ; COMMAND=/bin/systemctl enable qemu-guest-agent
May 03 14:07:59 localhost.localdomain sudo[8162]: pam_unix(sudo:session): session opened for user root by root(uid=0)
May 03 14:07:59 localhost.localdomain polkitd[624]: Registered Authentication Agent for unix-process:8164:19324 (system bus name :1.24 [/usr/bin/pkttyagent --notify-fd 5 --fallback], object
May 03 14:07:59 localhost.localdomain systemd[1]: Reloading.
May 03 14:07:59 localhost.localdomain polkitd[624]: Unregistered Authentication Agent for unix-process:8164:19324 (system bus name :1.24, object path /org/freedesktop/PolicyKit1/Authenticati
May 03 14:07:59 localhost.localdomain sudo[8162]: pam_unix(sudo:session): session closed for user root
May 03 14:08:01 localhost.localdomain polkitd[624]: Registered Authentication Agent for unix-process:8182:19565 (system bus name :1.25 [/usr/bin/pkttyagent --notify-fd 5 --fallback], object
May 03 14:09:31 localhost.localdomain systemd[1]: Job dev-virtio\x2dports-org.qemu.guest_agent.0.device/start timed out.
May 03 14:09:31 localhost.localdomain systemd[1]: Timed out waiting for device dev-virtio\x2dports-org.qemu.guest_agent.0.device.
-- Subject: Unit dev-virtio\x2dports-org.qemu.guest_agent.0.device has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit dev-virtio\x2dports-org.qemu.guest_agent.0.device has failed.
--
-- The result is timeout.
May 03 14:09:31 localhost.localdomain systemd[1]: Dependency failed for QEMU Guest Agent.
-- Subject: Unit qemu-guest-agent.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit qemu-guest-agent.service has failed.
--
-- The result is dependency.
May 03 14:09:31 localhost.localdomain systemd[1]: Job qemu-guest-agent.service/start failed with result 'dependency'.
May 03 14:09:31 localhost.localdomain polkitd[624]: Unregistered Authentication Agent for unix-process:8182:19565 (system bus name :1.25, object path /org/freedesktop/PolicyKit1/Authenticati
May 03 14:09:31 localhost.localdomain systemd[1]: Job dev-virtio\x2dports-org.qemu.guest_agent.0.device/start failed with result 'timeout'.
有人可以帮助我吗，非常感谢。
我也是，请帮助我，qemu-guset-agent 有很多问题