DevOps project

The goal of this project is to demonstrate how to use some tools to aid with the creation of virtual machines and configure software on them.

Creating Virtual Machine

• Installed vagrant.
• Installed VirtualBox. Other virtual machine providers do exist.

When creating a VM with vagrant, it will create a Vagrantfile in the current directory as well as a hidden directory (.vagrant). Vagrant only allows one virtual machine configuration per directory, so to organize your VMs:

• mkdir -p /boxes/ansible; cd /boxes/ansible

Initialized a virtual machine. ubuntu/trusty64 is one default image. A list of other virtual machine images can be found here.

vagrant init ubuntu/trusty64

Started up the virtual machine.

vagrant up

Then

vagrant ssh

Connection with the machine established.

Vagrantfile

The Vagrantfile will contain some settings to adjust for memory, networking, etc. The Vagrantfile for this project can be found here

  config.vm.provider :virtualbox do |vb|
     # fix crappy dns
     # https://serverfault.com/questions/453185/vagrant-virtualbox-dns-10-0-2-3-not-working
     vb.customize ["modifyvm", :id, "--natdnshostresolver1", "on"]
  end

Virtualbox Networking

In virtualbox, VMs typically have four ways to set up the network:

• Network Address Translation (NAT), which is the default,
• Bridged,
• Internal network
• Host Only (Recommended).

Unlike the first virtual machine, we cannot use the default mode, because there will be no way for the ansible VM to talk to the node VM. Instead, choose between bridged or host-only. Private networking (Host-only) is the recommended setting for Linux/Mac/Windows 10.

Uncommented the following line in Vagrantfile:

config.vm.network "private_network", ip: "192.168.33.10"

Then ran, vagrant reload.

Ansible

Ansible is a tool for configuring and coordinating software on multiple machines. In general, Ansible (like Salt, Chef, and Puppet), use a central server that controls other nodes. Unlike the other tools, Ansible does not require a client service to run on the nodes. It's a "push" type CM tool rather than a "pull" type.

Setting up Ansible

Followed these steps to install Ansible on your configuration server.

ansible-box> $ sudo apt-add-repository ppa:ansible/ansible
ansible-box> $ sudo apt-get update
ansible-box> $ sudo apt-get install ansible

Setting up inventory file and ssh keys

An inventory file allows ansible to define, group, and coordinate configuration management of multiple machines. At the most basic level, it basically lists the names of an asset and details about how to connect to it.

Created a inventory file that contains something like the following:

[nodes]
192.168.33.100 ansible_ssh_user=vagrant ansible_ssh_private_key_file=./keys/node0.key

Inventory file can be found here.

Setting up ssh keys

To automatically connect to our server without having to manually authenicate each connection, use a public/private key for ssh, ssh into our node VM from the Ansible Server automatically.

On the host machine, cd /boxes/node0. Then ran vagrant ssh-config to get path of the private_key of node0, opened it up and copied contents into textfile.

Inside the configuration server, created a keys/node0.key file that contained the private_key previously copied. Set the correct permissions by chmod 500 keys/node0.key.

Tested the connection between ansible and node0:

ssh -i keys/node0.key vagrant@192.168.1.100

Ansible in action

Now, ran the ping test again to make sure we can actually talk to the node!

ansible all -m ping -i inventory -vvvv

Ansible Playbook

Playbooks are Ansible’s configuration, deployment, and orchestration language. They can describe a policy you want your remote systems to enforce, or a set of steps in a general IT process.

Playbooks are designed to be human-readable and are developed in a basic text language. There are multiple ways to organize playbooks and the files they include.

All the configuration management, automation and testing is done through these Playbooks. In this project we initially started with the deploy.yml Playbook which has 3 different "tasks" or references 3 different Playbooks, all dedicated to different tasks. The first is the dependencies.yml Playbook which copies and executes some critical scripts in the server and also installs a few dependencies (pexpect). The main Playbook is the install_nginx.yml, which handles the task of deploying the web server, copying the HTML pages and setting the HTTP/HTTPS configuration. Finally, to run the automated test cases, we use the test.yml Playbook which runs the Selenium script to replicate a web browser and open the HTML page which we previously copied to make sure the server is configured properly.

Ran the Ansible Playbooks using the command

ansible-playbook -i inventory deploy.yml