实例执行所请求操作失败，实例处于错误状态。: 请稍后再试
[错误: Build of instance beaeb5e0-26eb-4044-ae14-bb87d509886d aborted: Failed to allocate the network(s), not rescheduling.].
解决办法：
修改/etc/nova/nova.conf文件
#Fail instance boot if vif plugging fails
vif_plugging_is_fatal = False
#Number of seconds to wait for neutron vif
#plugging events to arrive before continuing or failing
#(see vif_plugging_is_fatal). If this is set to zero and
#vif_plugging_is_fatal is False, events should not be expected to arrive at all.
vif_plugging_timeout = 0