Provisioning

Provisioning is the action of providing or supplying something for use (server provisioning, storage …).

Deployment

Deployment is the process of installing or upgrading an application/service into a server (installing or upgrading a web application for example).

Problems with both provisioning and deployment

• The process is repetitive and boring after its first iteration;
• So, it is a great target for automation;
• It may spread across multiple and heterogeneous systems (with different hardware e.g);
• Will probably have tweaks/updates overtime so it is a good idea to use versioning;
• Sometimes it is a time consuming task so it’s probably best to let the machine do it and do something else during that time.

Configuration Management

It is a way of handling systematic system changes while maintaining integrity throughout its life cycle.

Recipes

A way of defining task automation via a set of directives expressed in a given language:

Example

#!/bin/sh  
username=deployer  
apt-get -y update  
apt-get -y upgrade  
apt-get -y install vim-nox openntpd sudo whois aptitude  
useradd -G sudo -p "password" -s /bin/bash -m $username  
mkdir -p /home/$username/.ssh  
chmod 700 /home/$username/.ssh  
chown $username: /home/$username/.ssh  
echo "public_key" >> /home/$username/.ssh/authorized_keys  
chmod 600 /home/$username/.ssh/authorized_keys  
chown $username: /home/$username/.ssh/authorized_keys

Ansible

Ansible is an open-source tool used for configuration management application deployment, intra-service orchestration, and provisioning.

• Agentless recipe execution via SSH or locally:
  • Target hosts are defined in the inventory.
• Recipes are expressed in YAML:
  • Recipes are created via modules and task directives;
  • Recipes are organized into roles and playbooks.
• Tasks only run if the target differes from the expected result(idempotency).

How Ansible Works

• Ansible is operated from a Management Node, where you write and execute your playbooks and commands;
• The list of hosts to be managed by Ansisble is specified in the Inventory file;
• Ansible connects to remote hosts using SSH and executes the set of tasks defined in a playbook.