在使用 vagrant up 的时候，报错如下：
➜ centos7 vagrant up
Bringing machine 'vm-centos7' up with 'virtualbox' provider...
==> vm-centos7: Importing base box 'centos7'...
==> vm-centos7: Matching MAC address for NAT networking...
==> vm-centos7: Setting the name of the VM: centos7
==> vm-centos7: Clearing any previously set network interfaces...
==> vm-centos7: Preparing network interfaces based on configuration...
vm-centos7: Adapter 1: nat
==> vm-centos7: Forwarding ports...
vm-centos7: 22 (guest) => 2222 (host) (adapter 1)
==> vm-centos7: Running 'pre-boot' VM customizations...
==> vm-centos7: Booting VM...
There was an error while executing `VBoxManage`, a CLI used by Vagrant
for controlling VirtualBox. The command and stderr is shown below.
Command: ["startvm", "e8b18a27-5677-4bde-a611-5fae8f39128c", "--type", "headless"]
Stderr: VBoxManage: error: The virtual machine 'centos7' has terminated unexpectedly during startup with exit code 1 (0x1)
VBoxManage: error: Details: code NS_ERROR_FAILURE (0x80004005), component MachineWrap, interface IMachine
通过错误描述及网上搜索，确定这是由于对应的虚拟机异常关闭引发的异常，最终解决方案是：把 Vagrant 和 VirtualBox 重新安装一遍。
