这篇博客里说的很明白 http://razius.com/articles/launching-services-after-vagrant-mount/

原因是启动nginx的时候本地目录还没映射到虚拟机，nginx当然启动不了，解决办法就是在目录映射完以后再次启动nginx。

vi /etc/init/vagrant.conf;

加入以下内容：

# nginx
description "nginx http daemon"
author "Silviu Tantos"

# Listen and start after the vagrant-mounted event
start on vagrant-mounted
stop on runlevel [!2345]

env DAEMON=/usr/local/nginx/sbin/nginx
env PID=/usr/local/nginx/logs/nginx.pid

expect fork
respawn
respawn limit 10 5

pre-start script
        $DAEMON -t
        if [ $? -ne 0 ]
                then exit $?
        fi
end script

exec $DAEMON