有时候经常登录某台主机，会懒得输入密码，输入个用户名登录，像我这种更懒的，密码也懒得输入：
创建虚拟机：centos7
HuaiqingdeMBP:~ huaiqingcheng$ vagrant box add centos7 /Users/huaiqingcheng/Downloads/centos-7.0-x86_64.box
==> box: Box file was not detected as metadata. Adding it directly...
==> box: Adding box ‘centos7‘ (v0) for provider:
box: Unpacking necessary files from: file:///Users/huaiqingcheng/Downloads/centos-7.0-x86_64.box
==> box: Successfully added box ‘centos7‘ (v0) for ‘virtualbox‘!
查看虚拟机
HuaiqingdeMBP:~ huaiqingcheng$ vagrant box list
centos7 (virtualbox, 0)
centos7_1 (virtualbox, 0)
centos7_2 (virtualbox, 0)
centos7_3 (virtualbox, 0)
centos7_4 (virtualbox, 0)
ubuntu_1204_1 (virtualbox, 0)
初始化虚拟机
HuaiqingdeMBP:~ huaiqingcheng$ cd ./vagrant/
HuaiqingdeMBP:vagrant huaiqingcheng$ vagrant init centos7
A `Vagrantfile` has been placed in this directory. You are now
ready to `vagrant up` your first virtual environment! Please read
the comments in the Vagrantfile as well as documentation on
`vagrantup.com` for more information on using Vagrant.
桥接并且开启虚拟机（编辑vagrantfile文件即可，网卡模式可以随意自己选择，我选择了桥接，省事）
HuaiqingdeMBP:vagrant huaiqingcheng$ vagrant up
Bringing machine ‘default‘ up with ‘virtualbox‘ provider...
==> default: Importing base box ‘centos7‘...
==> default: Matching MAC address for NAT networking...
==> default: Setting the name of the VM: vagrant_default_1490616990534_7712
==> default: Clearing any previously set forwarded ports...
==> default: Clearing any previously set network interfaces...
==> default: Available bridged network interfaces:
1) en0: Wi-Fi (AirPort)
2) en5: USB Ethernet(?)
3) en1: Thunderbolt 1
4) en2: Thunderbolt 1
5) en3: Thunderbolt 18
6) en4: Thunderbolt 20
7) p2p0
8) awdl0
9) bridge0
==> default: When choosing an interface, it is usually the one that is
==> default: being used to connect to the internet.
default: Which interface should the network bridge to? 1
==> default: Preparing network interfaces based on configuration...
default: Adapter 1: nat
default: Adapter 2: bridged
==> 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: 4.3.28
default: VirtualBox Version: 5.1
==> default: Configuring and enabling network interfaces...
==> default: Mounting shared folders...
default: /vagrant => /Users/huaiqingcheng/vagrant
虚机地址
inet 192.168.0.113 netmask 255.255.255.0
使用openssh实现免密码登录（仅输入用户名就可以了）
原理：使用公钥认证(私钥加密公钥解密可以进行身份验证)
客户端生成一对密钥（public key和private key），通过将生成的公钥保存到需要认证的服务器的~/.ssh/authriedkey文件中，并且将.ssh目录的权限设置为644、authrizedkey权限设置为600即可
---
ssh密钥生成
HuaiqingdeMBP:vagrant huaiqingcheng$ ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/Users/huaiqingcheng/.ssh/id_rsa):
/Users/huaiqingcheng/.ssh/id_rsa already exists.
Overwrite (y/n)? y
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /Users/huaiqingcheng/.ssh/id_rsa.
Your public key has been saved in /Users/huaiqingcheng/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:CCRo8ATutB5d8kXw2ApP0i2EB3yoPzWkPOnkjXHX4fw huaiqingcheng@HuaiqingdeMBP.lan
The key‘s randomart image is:
+---[RSA 2048]----+
|+o+.=o.. |
|o+ *o+* . |
|.o++B* =+ . |
|o.oBO=+o + |
| +=.B++ S . |
|. .* . E |
| . . |
| |
| |
+----[SHA256]-----+
ssh-copy-id 复制公钥（需要输入一次用户密码）
HuaiqingdeMBP:vagrant huaiqingcheng$ ssh-copy-id root@192.168.0.113
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/Users/huaiqingcheng/.ssh/id_rsa.pub"
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
root@192.168.0.113‘s password:
Number of key(s) added: 1
Now try logging into the machine, with: "ssh ‘root@192.168.0.113‘"
and check to make sure that only the key(s) you wanted were added.
测试完成，免密码，需要输入用户名：
HuaiqingdeMBP:vagrant huaiqingcheng$ ssh root@192.168.0.113
Last login: Mon Mar 27 14:30:10 2017
Welcome to your Vagrant-built virtual machine.
[root@bogon ~]#
或者手动复制公钥/Users/huaiqingcheng/.ssh/id_rsa.pub到目标虚机/root/.ssh/authorized_keys文件中，~/.ssh目录的权限700，authorized_key的权限为600
用openssh实现免用户名+密码登录
在～/.ssh/目录下建立config文件,编辑内容，绑定用户名和公钥
Host 192.168.0.113
HostName 192.168.0.113
User root
Port 22
IdentityFile ~/.ssh/id_rsa
测试
HuaiqingdeMBP:vagrant huaiqingcheng$ ssh 192.168.0.113
Last login: Mon Mar 27 14:33:19 2017 from 192.168.0.101
Welcome to your Vagrant-built virtual machine.
[root@bogon ~]#
ok，拜拜
原文地址：http://yaotongshaonian.blog.51cto.com/11001675/1910906
