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How To Build a Custom CentOS 7 Box in Vagrant (OSX Yosemite) From Scratch

Are you familiar with Vagrant? Beside the official definition Why Vagrant, in case you need a fast and solid environment to try out your software on VMs, then you have to give Vagrant a try because it can be seen as a wrapper on top of virtualization software that can speed up your work a lot. At the end of this tutorial you will be able to start new personalized machines in a matter of seconds.

In this How To we are going to prepare a Vagrant local environment box VM based on CentOS 7 minimal image, with dev support and some basic improvements.

Preliminary Steps:

Create a New Virtual Machine on Virtual Box with the following settings:

  • Remove audio and USB
  • New Virtual Disk: [Type: VMDK, Size: 40 GB]
  • Verify that your main network is NAT Add this port-forwarding rule: [Name: SSH, Protocol: TCP, Host IP: blank, Host Port: 2222, Guest IP: blank, Guest Port: 22]
  • Mount your CentOS 7 iso image and startup the VM

During installation, pay attention to the following steps:

  • create a user vagrant with password vagrant and check the administrator option (click twice Done to accept this insecure password)
  • set root password as vagrant (twice Done again)

After Reboot do the following steps:

  • If you do not have a pair of RSA keys, generate these in OSX Terminal with the following command, leave password blank:

ssh-keygen -t rsa

Example: OSX Terminal ssh-keygen -t rsa

We will need those two files id_rsa and id_rsa.pub in the following steps.

  • login into the VM as root doing ssh root@127.0.0.1 -p 2222 using password vagrant

If you have a LOCALE error inside the VM console, then you can solve the problem doing the following in OSX Terminal:

(OPTIONAL) LOCALE PROBLEM ON OSX via SSH

prevent sending LC_ALL variable to the server:

edit /etc/ssh_config and comment the following line with a #:

# SendEnv LANG LC_*

Setup the CentOS VM with base software:

yum groupinstall base

Configure SSH with no password login, this is crucial because without, Vagrant has a problem with ssh’ing VM asking for password:

  • vi /etc/ssh/sshd_config

  • set no Password Authentication:

PasswordAuthentication no

Setup the vagrant user to be able to execute sudo commands without prompting you for a password:

visudo -f /etc/sudoers.d/vagrant

add in that file:

vagrant ALL=(ALL) NOPASSWD: ALL

and add the following line to the sudoers file doing visudo:

Defaults:vagrant !requiretty

  • test the configuration with the following command:

sudo pwd

It will return the current working directory without asking for a password. If you are prompted for a password, something is wrong.

Install the public key id_rsa.pub in the VM

This is the way Vagrant will communicate with the VM. In OSX I had problems with “insecure vagrant key” and after googling a lot I realized that creating a fresh pair of keys solved the problem:

mkdir -p /home/vagrant/.ssh
chmod 0700 /home/vagrant/.ssh
vi /home/vagrant/.ssh/authorized_keys

copy id_rsa.pub content in this file (or use scp to transfer the file into the VM)

Example file content: ssh authorized_keys example

chmod 0600 /home/vagrant/.ssh/authorized_keys
chown -R vagrant:vagrant /home/vagrant/.ssh
service sshd restart

Install Guest Tools

  • Host-D to mount Guest Tools CD-ROM (if centos iso is mounted, a screen like the following appears and you have to select force unmount) VirtualBox Accept

yum install gcc make yum install “kernel-devel-uname-r == $(uname -r)” mount /dev/sr0 /mnt -r cd /mnt ./VBoxLinuxAdditions.run

Enhance your Centos bash experience with these files:

  • .vimrc change colorscheme and add command to clear search in VIM
  • .bashrc add a great command prompt for bash
  • .dircolors I hate that blue color on shell folders…

source .bashrc

Note

copy the same files in /root folder and

vi /etc/hostname centos7-enhanced.localdomain

Correct vagrant 1.7.2 installation because of this bug

  • From OSX Terminal (HOST machine) do the following:

sudo vi /opt/vagrant/embedded/gems/gems/vagrant-1.7.2/plugins/communicators/ssh/communicator.rb

line 171 : add .env after @machine :

@machine.env.data_dir.join("private_key").open("w+") do |f|

vagrant file correction

  • Without shutting down the VM, open a new OSX Terminal, create a folder and write the following:

vagrant package --base vagrant-centos7-enhanced

You can rename the file with:

mv package.box centos7-enhanced.box

Correct execution

### Test your new base BOX

vagrant box add centos7 centos7-enhanced.box

vagrant init centos7

  • modify Vagrantfile with the follwing, so you tell vagrant to use your private key to SSH without prompting for password:
  # SSH Agent Forwarding
  #
  # Enable agent forwarding on vagrant ssh commands. This allows you to use ssh keys
  # on your host machine inside the guest. See the manual for `ssh-add`.
  config.ssh.private_key_path = '~/.ssh/id_rsa'
  config.ssh.forward_agent = true
  • to start the brand new box execute the following:

vagrant up

You can open other shells in the VM by executing:

vagrant ssh

If you want to ssh with standard commands, follow this link SSH login without password.

References:

SSH login without password

StackOverflow Kernel Devel Differences

Vagrant package problem resolution

SSH Login without password

SSH Config Reference

install tools on centos 7 minimal

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