正在学习Docker Swarm，接触到了Vagrant。Vagrant是一个创建虚拟机的技术，可以把它认为是一个Vmware，它让我们可以通过代码的方式快速地、可重复地创建针对不同虚拟环境的虚拟机，包括Virtualbox、AWS、Docker等。它使得我们可以一次性地、自动创建多个环境相同的虚拟机，对于软件开发和测试尤其有用，以下是在使用过程中常用到的一些基本命令。

1. 显示当前版本

# vagrant --version

Vagrant 2.0.2

2. 列出所有Box

#vagrant box list

iamseth/rhel-7.3 (virtualbox, 1.0.0)

3. 添加一个Box

#vagrant box add [options] <name, url, or path>

1）可以从https://app.vagrantup.com/boxes/search下载各种Vagrant映像文件

#vagrant box add ubuntu/trusty64

2) 通过指定的URL添加远程box

#vagrant box add https://atlas.hashicorp.com/ubuntu/boxes/trusty64

3) 添加一个本地box

命令格式如下

# vagrant box add {box_name} {file_path}

示例如下:

# vagrant box add CentOS7.1 file:///D:/Work/VagrantBoxes/CentOS-7.1.1503-x86_64-netboot.box

4. 初始化一个新VM

# vagrant init ubuntu/trustry64

此命令会在当前目录创建一个名为Vagrantfile的配置文件，内容大致如下：

Vagrant.configure("2") do |config|

  config.vm.box = "ubuntu/trusty64"

end

当在此目录启动Vagrant后，Vagrant会从互联网下载“ubuntu/trusty64”这个box到本地，并使用它作为VM的映像。

5. 初始化一个新VM

# vagrant up

如果我们想启动任意VM，首先进入有Vagrantfile配置文件的目录，然后执行上面的命令。控制台的输出通常如下：

Bringing machine 'default' up with 'virtualbox' provider...

==> default: Importing base box 'ubuntu/trusty64'...

==> default: Matching MAC address for NAT networking...

==> default: Checking if box 'ubuntu/trusty64' is up to date...

==> default: Setting the name of the VM: start_default_1518789015107_16928

==> default: Clearing any previously set forwarded ports...

Vagrant is currently configured to create VirtualBox synced folders with

the `SharedFoldersEnableSymlinksCreate` option enabled. If the Vagrant

guest is not trusted, you may want to disable this option. For more

information on this option, please refer to the VirtualBox manual:

  https://www.virtualbox.org/manual/ch04.html#sharedfolders

This option can be disabled globally with an environment variable:

  VAGRANT_DISABLE_VBOXSYMLINKCREATE=1

or on a per folder basis within the Vagrantfile:

  config.vm.synced_folder '/host/path', '/guest/path', SharedFoldersEnableSymlinksCreate: false

==> default: Clearing any previously set network interfaces...

==> default: Preparing network interfaces based on configuration...

    default: Adapter 1: nat

==> default: Forwarding ports...

    default: 22 (guest) => 2222 (host) (adapter 1)

==> default: Booting VM...

==> default: Waiting for machine to boot. This may take a few minutes...

    default: SSH address: 127.0.0.1:2222

    default: SSH username: vagrant

    default: SSH auth method: private key

    default:

    default: Vagrant insecure key detected. Vagrant will automatically replace

    default: this with a newly generated keypair for better security.

    default:

    default: Inserting generated public key within guest...

    default: Removing insecure key from the guest if it's present...

    default: Key inserted! Disconnecting and reconnecting using new SSH key...

==> default: Machine booted and ready!

==> default: Checking for guest additions in VM...

    default: The guest additions on this VM do not match the installed version of

    default: VirtualBox! In most cases this is fine, but in rare cases it can

    default: prevent things such as shared folders from working properly. If you see

    default: shared folder errors, please make sure the guest additions within the

    default: virtual machine match the version of VirtualBox you have installed on

    default: your host and reload your VM.

    default:

    default: Guest Additions Version: 4.3.36

    default: VirtualBox Version: 5.2

==> default: Mounting shared folders...

    default: /vagrant => /Users/qianlong/DockerProjects/vagrant/start

6.启用SSH登陆VM

进入Vagrantfile配置文件所在的目录，执行以下命令：

# vagrant ssh

如果需要从虚拟机中退出，直接在虚拟机中的命令行输入exit命令即可

7. 查看VM当前的状态

进入Vagrantfile配置文件所在的目录，执行以下命令：

# vagrant status

如果VM正在运行，你可以在控制台中看到如下信息：

Current machine states:

default                   running (virtualbox)

The VM is running. To stop this VM, you can run `vagrant halt` to

shut it down forcefully, or you can run `vagrant suspend` to simply

suspend the virtual machine. In either case, to restart it again,

simply run `vagrant up`.

8.关闭VM

进入Vagrantfile配置文件所在的目录，执行以下命令：

# vagrant halt

9.销毁VM

命令格式如下：

vagrant destory [name|id]

示例如下：

# vagrant destroy ubuntu/trusty64

如果我们是使用了默认的虚拟机名"default"，那其实我们可以直接输入如下命令销毁VM

# vagrant desotry

运行结果如下：

    default: Are you sure you want to destroy the 'default' VM? [y/N] y

==> default: Forcing shutdown of VM...

==> default: Destroying VM and associated drives...

需要注意的是，我们要慎重使用该命令，该命令会停止VM的运行，并销毁所有在VM中创建的资源