1.先在镜像站找到需要镜像，本例为ubuntu/xenial64,版本号最新的为：v20190215.0.0

2.获取最新的下载地址，出现下载地址后，使用curl+c停止

$ vagrant box add ubuntu/xenial64
==> box: Loading metadata for box 'ubuntu/xenial64'
    box: URL: https://vagrantcloud.com/ubuntu/xenial64
==> box: Adding box 'ubuntu/xenial64' (v20190215.0.0) for provider: virtualbox
    box: Downloading: https://vagrantcloud.com/ubuntu/boxes/xenial64/versions/20190215.0.0/providers/virtualbox.box
    box: Download redirected to host: cloud-images.ubuntu.com
    box: Progress: 0% (Rate: 11010/s, Estimated time remaining: 12:02:22)^C==> box: Waiting for cleanup before exiting...
==> box: Box download was interrupted. Exiting.

https://vagrantcloud.com/ubuntu/boxes/xenial64/versions/20190215.0.0/providers/virtualbox.box为下载地址，使用下载工具进行下载,并且重命名为“ubuntu_xenial64_20190215.box”

3.新建配置文件“metadata.json”,和下载的“ubuntu_xenial64_20190215.box”放在一级目录

{
    "name": "ubuntu/xenial64",
    "versions": 
    [
        {
            "version": "20190215.0.0",
            "providers": [
                {
                  "name": "virtualbox",
                  "url": "ubuntu_xenial64_20190215.box"
                }
            ]
        }
    ]
}

4.添加box
vagrant box add metadata.json