Ansible is an open-source software provisioning, configuration management, and application-deployment tool. It runs on many Unix-like systems and can configure both Unix-like systems as well as Microsoft Windows. It includes its own declarative language to describe system configuration.
Ansible was written by Michael DeHaan and acquired by Red Hat in 2015. Ansible is agentless, temporarily connecting remotely via SSH or Windows Remote Management (allowing remote PowerShell execution) to do its tasks.
Definition of Ansible
Ansible is a powerful IT automation tool that you can quickly learn. It’s simple enough for everyone in IT yet powerful enough to automate complex multi-tier applications. It’s also agentless, which means that you don’t need to install any software on the client systems you want to automate. You also don’t have to set up a separate management structure. Instead, Ansible uses SSH keys for authentication and allows you to start managing systems right away.
Ansible uses a simple language called YAML in the form of Ansible Playbooks which allows you to describe your automation jobs in a way that approaches plain English.
Ansible Modules
Ansible works by connecting to your nodes and pushing out small programs, called "Ansible Modules" to them. These programs are written to be resource models of the desired state of the system. Ansible then executes these modules (over SSH by default), and removes them when finished.
Your library of modules can reside on any machine, and there are no servers, daemons, or databases required. Typically you'll work with your favorite terminal program, a text editor, and probably a version control system to keep track of changes to your content.
Ansible Playbooks
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, and we’ll offer up some suggestions on that and making the most out of Ansible.
Explanation of Ansible
Ansible is designed for multi-tier deployments since day one, so it models your IT infrastructure by describing how all of your systems inter-relate, rather than just managing one system at a time.
It uses no agents and no additional custom security infrastructure, so it's easy to deploy - and most importantly, it uses a very simple language (YAML, in the form of Ansible Playbooks) that allow you to describe your automation jobs in a way that approaches plain English.
How Ansible Works
On the management machine, Ansible is installed and most of its work is done through a command-line tool. Configuration files are mainly written in the YAML data serialization format due to its expressive nature and its similarity to popular markup languages. Ansible can interact with clients through either command line tools or through its configuration scripts called Playbooks.
Playbooks are a completely different way to use ansible than in ad-hoc task execution mode, and are particularly powerful. Simply put, playbooks are the basis for a really simple configuration management and multi-machine deployment system, unlike any that already exist, and one that is very well suited to deploying complex applications.
Ansible Architecture
Ansible works by connecting to your nodes and pushing out small programs, called "Ansible modules" to them. These programs are written to be resource models of the desired state of the system. Ansible then executes these modules (over SSH by default), and removes them when finished.
Your library of modules can reside on any machine, and there are no servers, daemons, or databases required. Typically you'll work with your favorite terminal program, a text editor, and probably a version control system to keep track of changes to your content.
History of Ansible
Ansible was created by Michael DeHaan, the author of the provisioning server application Cobbler and co-author of the Fedora Unified Network Controller. DeHaan announced Ansible in a blog post in March 2012. Ansible, Inc. (originally AnsibleWorks, Inc.) was the company set up to commercially support and sponsor Ansible. Red Hat acquired Ansible in October 2015.
Ansible is included as part of the Fedora distribution of Linux, owned by Red Hat, and is also available for Red Hat Enterprise Linux, CentOS, and Scientific Linux via Extra Packages for Enterprise Linux (EPEL) as well as for other operating systems. Ansible is also available for Ubuntu via a PPA, and for other Linux distributions via python-pip.
Ansible's Growth
Since its creation, Ansible has grown to become one of the most popular tools for IT automation, with a large and active community of users. This growth has been driven by a number of factors, including its simplicity, ease of use, and the fact that it is open source, which means that it is free to use and can be customized to meet the specific needs of individual users.
Ansible's growth has also been fueled by the increasing demand for automation in the IT industry. As businesses have become more reliant on technology, the need to automate routine tasks, streamline processes, and improve efficiency has become more important. Ansible has been able to meet this need, providing businesses with a powerful tool that can help them to achieve these goals.
Acquisition by Red Hat
In October 2015, Red Hat announced its acquisition of Ansible, Inc. This acquisition was seen as a significant endorsement of Ansible and a recognition of its potential. It also provided Ansible with the resources and support of one of the world's leading providers of open source solutions.
Since the acquisition, Red Hat has continued to support the development of Ansible, helping to ensure that it remains at the forefront of IT automation. This has included the release of new versions of Ansible, as well as the development of additional features and capabilities.
Use Cases of Ansible
Ansible can be used for a wide range of tasks, from setting up a simple web server to managing a complex multi-tier application environment. Some of the most common use cases for Ansible include configuration management, application deployment, and orchestration.
Configuration management is one of the most common use cases for Ansible. This involves using Ansible to manage the configuration of your systems, ensuring that they are always in the desired state. This can include tasks such as installing and updating software packages, managing services, and setting up users and groups.
Application Deployment
Ansible can also be used to automate the deployment of your applications. This can involve tasks such as pulling the latest version of your application from a version control system, installing any necessary dependencies, and starting the application.
Ansible's simple, human-readable syntax makes it easy to define the steps required to deploy your application, and its agentless architecture means that you don't need to install any additional software on your servers. This makes Ansible a powerful tool for application deployment.
Orchestration
Orchestration is another common use case for Ansible. This involves using Ansible to manage the interactions between different systems in your environment.
For example, you might use Ansible to automate the process of scaling up your application in response to increased demand. This could involve tasks such as creating new virtual machines, configuring them to run your application, and adding them to a load balancer.
Examples of Ansible
Let's take a look at some specific examples of how Ansible can be used. These examples will demonstrate the power and flexibility of Ansible, and show how it can be used to automate a wide range of tasks.
One common use case for Ansible is to automate the process of setting up a new server. This can involve a wide range of tasks, from installing and configuring software, to setting up users and groups, to configuring network settings. With Ansible, you can define all of these tasks in a single playbook, and then run that playbook to set up your server automatically.
Automating Web Server Setup
For example, let's say you're setting up a web server. You could create an Ansible playbook that installs the Apache web server, configures it to serve your website, and sets up the necessary firewall rules. Then, whenever you need to set up a new web server, you can simply run this playbook and have your server up and running in minutes.
This not only saves you time, but also ensures that your server is set up consistently every time. This can be particularly useful in larger environments, where consistency across servers is important.
Automating Application Deployment
Another common use case for Ansible is automating the deployment of applications. For example, let's say you have a web application that you need to deploy to a number of servers. You could create an Ansible playbook that pulls the latest version of your application from your version control system, installs any necessary dependencies, and starts the application.
Then, whenever you need to deploy a new version of your application, you can simply run this playbook. This not only saves you time, but also ensures that your application is deployed consistently across all of your servers.
Automating Infrastructure Scaling
Ansible can also be used to automate the process of scaling your infrastructure. For example, let's say you have a web application that needs to scale up in response to increased demand. You could create an Ansible playbook that creates new virtual machines, configures them to run your application, and adds them to your load balancer.
Then, whenever you need to scale up your infrastructure, you can simply run this playbook. This not only saves you time, but also ensures that your infrastructure is scaled up consistently and correctly every time.