vagrant 是一个非常好用的工具，可以用它来在单台物理机器编程管理多个虚拟机(vms)。其支持原生VirtualBox，并同时提供了对VMware Fusion、Amazon EC2虚拟机集群的插件支持。
vagrant提供了极易使用、基于Ruby的内部DSL，允许用户使用它们的配置参数定义一个或多个虚拟机。另外，对于自动部署，vagrant支持多种机制：可以使用puppet，chef或者用于在vagrant配置文件中定义的所有虚拟机上自动安装软件程序和配置的shell脚本等。
所以，使用vagrant可以在运行着多台vm的系统上定义复杂的虚拟框架，是不是很酷?
vagrant的典型使用案例是以简单并且一致的方式构建工作或者开发环境。在Eligotech（原作者公司）公司里，开发人员正在开发一个产品，目标是让用户简单的使用Apache Hadoop、CDH(Cloudera的开源版本)。开发人员经常是为了测试需要在机器上安装hadoop环境。他们发现vagrant在这方面是一个非常便利的工具。
一个vagrant配置文件的例子，你们可以自行测试。你需要下载并安装vagrant（帮助地址）和virtualBox。所有东西都安装完毕后即可复制粘贴下面的文本保存为Vagrantfile，并将其放到一个目录下，比如VagrantHadoop.这个配置文件假定你机器内存至少32G，如果不适合可以自行编辑该文件。
# -*- mode: ruby -*-
# vi: set ft=ruby :
$master_script = <<SCRIPT
#!/bin/bash
cat > /etc/hosts <<EOF
127.0.0.1 localhost
# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
10.211.55.100 vm-cluster-node1
10.211.55.101 vm-cluster-node2
10.211.55.102 vm-cluster-node3
10.211.55.103 vm-cluster-node4
10.211.55.104 vm-cluster-node5
10.211.55.105 vm-cluster-client
EOF
apt-get install curl -y
REPOCM=${REPOCM:-cm4}
CM_REPO_HOST=${CM_REPO_HOST:-archive.cloudera.com}
CM_MAJOR_VERSION=$(echo $REPOCM | sed -e 's/cm\\([0-9]\\).*/\\1/')
CM_VERSION=$(echo $REPOCM | sed -e 's/cm\\([0-9][0-9]*\\)/\\1/')
OS_CODENAME=$(lsb_release -sc)
OS_DISTID=$(lsb_release -si | tr '[A-Z]' '[a-z]')
if [ $CM_MAJOR_VERSION -ge 4 ]; then
cat > /etc/apt/sources.list.d/cloudera-$REPOCM.list <<EOF
deb [arch=amd64] $CM_REPO_HOST/cm$CM_MAJOR_VERSION/$OS_DISTID/$OS_CODENAME/amd64/cm $OS_CODENAME-$REPOCM contrib
deb-src $CM_REPO_HOST/cm$CM_MAJOR_VERSION/$OS_DISTID/$OS_CODENAME/amd64/cm $OS_CODENAME-$REPOCM contrib
EOF
curl -s $CM_REPO_HOST/cm$CM_MAJOR_VERSION/$OS_DISTID/$OS_CODENAME/amd64/cm/archive.key > key
apt-key add key
rm key
fi
apt-get update
export DEBIAN_FRONTEND=noninteractive
apt-get -q -y --force-yes install Oracle-j2sdk1.6 cloudera-manager-server-db cloudera-manager-server cloudera-manager-daemons
service cloudera-scm-server-db initdb
service cloudera-scm-server-db start
service cloudera-scm-server start
SCRIPT
$slave_script = <<SCRIPT
cat > /etc/hosts <<EOF
127.0.0.1 localhost
# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
10.211.55.100 vm-cluster-node1
10.211.55.101 vm-cluster-node2
10.211.55.102 vm-cluster-node3
10.211.55.103 vm-cluster-node4
10.211.55.104 vm-cluster-node5
10.211.55.105 vm-cluster-client
EOF
SCRIPT
$client_script = <<SCRIPT
cat > /etc/hosts <<EOF
127.0.0.1 localhost
# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
10.211.55.100 vm-cluster-node1
10.211.55.101 vm-cluster-node2
10.211.55.102 vm-cluster-node3
10.211.55.103 vm-cluster-node4
10.211.55.104 vm-cluster-node5
10.211.55.105 vm-cluster-client
EOF
SCRIPT
Vagrant.configure("2") do |config|
config.vm.define :master do |master|
master.vm.box = "precise64"
master.vm.provider "vmware_fusion" do |v|
v.vmx["memsize"] = "4096"
end
master.vm.provider :virtualbox do |v|
v.name = "vm-cluster-node1"
v.customize ["modifyvm", :id, "--memory", "4096"]
end
master.vm.network :private_network, ip: "10.211.55.100"
master.vm.hostname = "vm-cluster-node1"
master.vm.provision :shell, :inline => $master_script
end