平时使用的 vagrant 集群配置实践。一个配置文件管理一个集群，嗯，相对于以前想玩一个集群需要搞 三个机器，想想之前，都是泪。这里要区分 vagrant box 配置，和虚拟机配置，3 台集群的虚拟机都是用同一版本 box 镜像。
核心配置说明：

config.vm.define :node1 do |node1|
     # 配置主机名
    node1.vm.hostname = "node1"
    # 配置私有 IP
    node1.vm.network "private_network", ip: "192.168.56.121"
    # 配置虚拟机提供者配置，我用的 virtualbox
    node1.vm.provider "virtualbox" do |v|
      # 配置在 virtualbox 中显示名字，不配置默认是 vagrant 自动生成的 id，
      # vagrant-globalstatus 可以查看 id
      v.name = "node1-121"
      # 配置内存大小
      v.memory = "1024"
      # 配置 CPU 核数
      v.cpus = "2"
    end
end
config.vm.define :node2 do |node2|
    node2.vm.hostname = "node2"
    node2.vm.network :private_network, ip: "192.168.56.122"
    node2.vm.provider "virtualbox" do |v|
        v.name = "node2-122"
        v.memory = "1024"
        v.cpus = "2"
    end
end
config.vm.define :node3 do |node3|
    node3.vm.hostname = "node3"
    node3.vm.network "private_network", ip: "192.168.56.123"
    node3.vm.provider "virtualbox" do |v|
        v.name = "node3-123"
        v.memory = "1024"
        v.cpus = "2"
    end
end

配置好之后 vagrant up 启动集群。启动成功后， vagrant ssh node1 即可登录集群服务器 1。
完整详细参考配置如下：

# -*- mode: ruby -*-
# vi: set ft=ruby :
# All Vagrant configuration is done below. The "2" in Vagrant.configure
# configures the configuration version (we support older styles for
# backwards compatibility). Please don't change it unless you know what
# you're doing.
Vagrant.configure("2") do |config|
# The most common configuration options are documented and commented below.
# For a complete reference, please see the online documentation at
# https://docs.vagrantup.com.
# Every Vagrant development environment requires a box. You can search for
# boxes at https://atlas.hashicorp.com/search.
config.vm.box = "mycentos7"
# Disable automatic box update checking. If you disable this, then
# boxes will only be checked for updates when the user runs
# `vagrant box outdated`. This is not recommended.
# config.vm.box_check_update = false
# Create a forwarded port mapping which allows access to a specific port
# within the machine from a port on the host machine. In the example below,
# accessing "localhost:8080" will access port 80 on the guest machine.
# config.vm.network "forwarded_port", guest: 80, host: 8080
# Create a private network, which allows host-only access to the machine
# using a specific IP.
# config.vm.network "private_network", ip: "192.168.56.155"
# Create a public network, which generally matched to bridged network.
# Bridged networks make the machine appear as another physical device on
# your network.
# config.vm.network "public_network"
# Share an additional folder to the guest VM. The first argument is
# the path on the host to the actual folder. The second argument is
# the path on the guest to mount the folder. And the optional third
# argument is a set of non-required options.
# config.vm.synced_folder "../data", "/vagrant_data"
# Provider-specific configuration so you can fine-tune various
# backing providers for Vagrant. These expose provider-specific options.
# Example for VirtualBox:
#
config.vm.define :web do |web|
    web.vm.hostname = "web"
    web.vm.network "private_network", ip: "192.168.33.10"
    config.vm.synced_folder "../php", "/usr/share/nginx/html"
    config.vm.synced_folder "nginx-conf", "/etc/nginx/conf.d"
    web.vm.network "forwarded_port", guest: 80, host: 80
    web.vm.provider "virtualbox" do |v|
        v.name = "web"
        v.memory = "2048"
        v.cpus = "1"
    end
end
config.vm.define :db1 do |db1|
    db1.vm.hostname = "db1"
    db1.vm.network :private_network, ip: "192.168.33.11"
    config.vm.synced_folder "../php", "/usr/share/nginx/html"
    config.vm.synced_folder "nginx-conf", "/etc/nginx/conf.d"
    db1.vm.network "forwarded_port", guest: 8081, host: 8081
    db1.vm.provider "virtualbox" do |v|
        v.name = "db1"
        v.memory = "1024"
        v.cpus = "1"
    end
end
config.vm.define :db2 do |db2|
    db2.vm.hostname = "db2"
    db2.vm.network :private_network, ip: "192.168.33.12"
    config.vm.synced_folder "../php", "/usr/share/nginx/html"
    config.vm.synced_folder "nginx-conf", "/etc/nginx/conf.d"
    db2.vm.network "forwarded_port", guest: 8082, host: 8082
    db2.vm.provider "virtualbox" do |v|
        v.name = "db2"
        v.memory = "1024"
        v.cpus = "1"
    end
end
config.vm.define :db3 do |db3|
    db3.vm.hostname = "db3"
    db3.vm.network :private_network, ip: "192.168.33.13"
    config.vm.synced_folder "../php", "/usr/share/nginx/html"
    config.vm.synced_folder "nginx-conf", "/etc/nginx/conf.d"
    db3.vm.network "forwarded_port", guest: 8083, host: 8083
    db3.vm.provider "virtualbox" do |v|
        v.name = "db3"
        v.memory = "1024"
        v.cpus = "1"
    end
end
#
# View the documentation for the provider you are using for more
# information on available options.
# Define a Vagrant Push strategy for pushing to Atlas. Other push strategies
# such as FTP and Heroku are also available. See the documentation at
# https://docs.vagrantup.com/v2/push/atlas.html for more information.
# config.push.define "atlas" do |push|
#   push.app = "YOUR_ATLAS_USERNAME/YOUR_APPLICATION_NAME"
# end
# Enable provisioning with a shell script. Additional provisioners such as
# Puppet, Chef, Ansible, Salt, and Docker are also available. Please see the
# documentation for more information about their specific syntax and use.
# config.vm.provision "shell", inline: <<-SHELL
#   apt-get update
#   apt-get upgrade
# SHELL
end

参考：https://favoorr.github.io/2017/01/06/vagrant-multiple-servers-cluster-config-best-practices/