What is Ansible? | IT Automation Tool Beginner’s Tutorial

What is Ansible? | IT Automation Tool Beginner’s Tutorial

Graphic of automation tools and gears integrating into a network representing what is ansible

In recent times, we at IOFLOOD have put a focus on optimizing our processes for Linux server deployment and management. During development, we looked into utilizing Ansible, an automation tool for repetitive tasks, server environment configuration, and deployment processes. We have compiled our findings into today’s article, to explain Ansible’s role in modern server management and inform our bare metal cloud hosting customers and fellow developers in the benefits of Ansible for infrastructure management.

In this guide, we will introduce you to Ansible, its features, and why it’s a game-changer in the world of IT automation. We’ll explore Ansible’s core functionality, delve into its advanced features, and even discuss common issues and their solutions.

So, let’s dive in and start mastering Ansible!

TL;DR: What is Ansible?

Ansible is an open-source software provisioning, configuration management, and application-deployment tool. You can install it with, sudo apt install ansible or sudo yum install ansible. You can then verify installation with ansible --version. It uses a simple, human-readable language (YAML) to define automation jobs, making it easy to manage and configure systems.

Here’s a simple example:

ansible all -m ping

# Output:
# host1 | success >> {
#     "changed": false,
#     "ping": "pong"
# }

In this example, we’re using Ansible’s ad-hoc command capability to ping all hosts in our inventory. The ansible command is followed by the group of hosts (in this case, all), the -m option specifies the module to use (ping in this case).

The output shows that the ping module has successfully reached host1 and returned a pong, indicating that the host is reachable.

This is just a basic use of Ansible, but there’s much more to learn about this powerful IT automation tool. Continue reading for a more detailed understanding of Ansible and its capabilities.

The Basics of Ansible

Ansible is an open-source automation tool, or platform, used for IT tasks such as configuration management, application deployment, intraservice orchestration and provisioning. It’s incredibly flexible, allowing you to automate just about anything, but it’s most often used for deploying applications and managing configurations of systems.

One of the key aspects of Ansible architecture is its simplicity. It operates on a master-node architecture, where the controlling machine (master) controls the nodes over SSH. The nodes are the machines where tasks are run, and the controlling machine is where Ansible is installed and run from.

But what makes Ansible really stand out is its ‘agentless’ architecture. Unlike other automation tools, Ansible doesn’t require any special software installed on the nodes. This makes it easy to manage systems without having to worry about any underlying software or firewall requirements.

Ansible uses a language called YAML (Yet Another Markup Language) for its playbook scripts. YAML is a human-readable data serialization standard, which makes it incredibly easy to understand and write Ansible scripts, even for beginners.

Let’s take a look at a simple Ansible playbook:

---
- hosts: webservers
  tasks:
  - name: ensure apache is at the latest version
    yum:
      name: httpd
      state: latest

In this example, we have a playbook that ensures Apache (a popular web server software) is at the latest version on all web servers. The hosts: webservers specifies the group of hosts the playbook should run on. The tasks: section lists out the jobs to be done. Here, there’s a single task named ensure apache is at the latest version. The yum: module is used to manage packages on RHEL/CentOS systems, specifying httpd (the package for Apache) and state: latest ensures that the latest version of the package is installed.

Running this playbook will ensure that all your web servers are running the latest version of Apache, providing a simple yet powerful example of Ansible’s capabilities.

Before going further, here are more basic commands that you should know while operating Ansible

TaskCommandExplanation
Install Ansible on Ubuntu/Debian:sudo apt update
sudo apt install ansible
Updates package lists and installs Ansible using the package manager.
Install Ansible on CentOS/RHEL:sudo yum install epel-release
sudo yum install ansible
Installs the EPEL repository (if needed) and then installs Ansible using the package manager.
Check Ansible Version:ansible --versionDisplays the installed version of Ansible.
Create Ansible Inventory File:nano inventory.iniOpens a text editor to create or edit the Ansible inventory file, which lists managed hosts.
Run Ansible Ad-Hoc Command:ansible all -i inventory.ini -m ping -u remote_user --becomeExecutes an ad-hoc command (ping in this case) on all hosts listed in the inventory file as the remote_user with privilege escalation.
Run Ansible Playbook:ansible-playbook -i inventory.ini playbook.ymlApplies configurations defined in a playbook (e.g., playbook.yml) to hosts listed in the inventory file.
Check Playbook Syntax:ansible-playbook --syntax-check playbook.ymlVerifies the syntax of a playbook without executing it.
Check Host Connectivity:ansible all -i inventory.ini -m pingTests connectivity to all hosts listed in the inventory file using the ping module.
Gather Facts from Hosts:ansible all -i inventory.ini -m setupGathers system facts from all hosts listed in the inventory file.
Run Playbook with Tags:ansible-playbook -i inventory.ini playbook.yml --tags "tag1,tag2"Executes specific tasks in a playbook that are tagged with “tag1” and “tag2”.
Install Package on Hosts:ansible all -i inventory.ini -m package -a "name=package_name state=present" --becomeInstalls a package (package_name) on all hosts with privilege escalation.
Restart Service on Hosts:ansible all -i inventory.ini -m service -a "name=service_name state=restarted" --becomeRestarts a service (service_name) on all hosts with privilege escalation.
Copy File to Hosts:ansible all -i inventory.ini -m copy -a "src=/path/to/local/file dest=/path/on/remote/file" --becomeCopies a file from the local system to a path on all hosts with privilege escalation.
Create User on Hosts:ansible all -i inventory.ini -m user -a "name=new_user state=present" --becomeCreates a new user (new_user) on all hosts with privilege escalation.
Remove User from Hosts:ansible all -i inventory.ini -m user -a "name=old_user state=absent" --becomeRemoves a user (old_user) from all hosts with privilege escalation.

Key Features of Ansible

As you become more comfortable with Ansible, you’ll start to appreciate some of its advanced features that make it such a powerful tool for IT automation.

Idempotency: Consistency Made Easy

One key feature of Ansible is its idempotency. In simple terms, idempotency means that you can run the same playbook multiple times and the result will always be the same. This is incredibly important in ensuring consistency across your IT infrastructure.

Agentless Architecture: No More Agent Worries

Unlike other automation tools, Ansible operates on an agentless architecture. This means that you don’t need to install any additional software (agents) on the nodes that Ansible manages. This makes Ansible easier to use and reduces the overhead of maintaining additional software.

Playbooks: The Heart of Ansible

Playbooks are at the heart of Ansible’s operation. They are simple, human-readable YAML files that describe the tasks that Ansible should perform. Playbooks can be as simple or as complex as you need them to be, allowing you to automate complex tasks with ease.

Let’s take a look at a more complex Ansible playbook:

---
- hosts: webservers
  vars:
    http_port: 80
    max_clients: 200
  remote_user: root
  tasks:
  - name: ensure apache is running
    service:
      name: httpd
      state: started
  - name: write the apache config file
    template:
      src: /srv/httpd.j2
      dest: /etc/httpd.conf
    notify:
    - restart apache
  handlers:
    - name: restart apache
      service:
        name: httpd
        state: restarted

This playbook does a few things. First, it defines some variables (http_port and max_clients) which can be used in tasks. It then ensures that the Apache service is running. Next, it writes the Apache config file using a template (httpd.j2) and notifies a handler to restart the Apache service if the config file changes. The handler is defined at the end of the playbook and restarts the Apache service when called.

Running this playbook on your web servers would ensure that they are all running Apache with the same configuration, demonstrating the power and flexibility of Ansible.

Ansible vs. Other IT Automation Tools

While Ansible is a powerful tool for IT automation, it’s not the only player in the field. Let’s take a look at how it compares to other popular IT automation tools such as Puppet, Chef, and SaltStack.

Puppet: The Established Veteran

Puppet is one of the oldest IT automation tools and is widely used in the industry. It uses a master-agent architecture and a declarative language to define system configuration.

file { '/tmp/testfile':
  ensure => file,
  owner  => 'root',
  group  => 'root',
  mode   => '0644',
  content => "Hello, Puppet!",
}

In this Puppet manifest, we’re defining a file resource. The manifest ensures that a file named ‘testfile’ exists in the ‘/tmp’ directory with specific ownership and permissions, and contains the text ‘Hello, Puppet!’.

Puppet’s strength lies in its maturity and wide community support. However, its learning curve is steeper than Ansible’s due to its own DSL (Domain Specific Language).

Chef: The Ruby Aficionado

Chef, like Puppet, is another veteran in the IT automation field. It uses a master-agent architecture and is written in Ruby, which means if you’re familiar with Ruby, you’ll feel at home with Chef.

file '/tmp/testfile' do
  content 'Hello, Chef!'
  mode '0755'
  owner 'root'
  group 'root'
end

In this Chef recipe, we’re creating the same file as in the Puppet example, but with Chef’s Ruby-based DSL.

Chef’s strength lies in its flexibility and the power of Ruby, but it also has a steep learning curve, especially if you’re not familiar with Ruby.

SaltStack: The Fast and Scalable

SaltStack, like Ansible, uses a YAML-based DSL for its configuration files, but it’s designed for speed and scalability. It’s capable of managing larger infrastructures more efficiently than either Puppet or Chef.

/tmp/testfile:
  file.managed:
    - contents: Hello, SaltStack!
    - mode: 644
    - user: root
    - group: root

In this SaltStack state file, we’re creating the same file as in the previous examples. SaltStack’s YAML-based DSL is similar to Ansible’s, making it relatively easy to learn.

SaltStack’s strength lies in its speed and scalability, but it’s not as widely used or as well-known as Puppet, Chef, or Ansible.

Why Choose Ansible?

Each of these tools has its strengths and weaknesses, and the best one for you depends on your specific needs. However, Ansible’s simplicity, ease of learning, and agentless architecture make it a strong contender for many IT automation tasks.

Troubleshooting Issues: Ansible

Like any tool, Ansible isn’t without its quirks. Here, we’ll discuss some common issues you might encounter when using Ansible and how to troubleshoot them.

Dealing with Connectivity Issues

One of the most common issues when using Ansible is dealing with connectivity issues. Ansible communicates with nodes via SSH, so any network or SSH configuration issues can lead to problems.

For example, if you’re trying to run a playbook and you encounter a ‘UNREACHABLE’ error, it’s likely there’s an issue with your SSH configuration or network connectivity.

ansible-playbook playbook.yml

# Output:
# host1 | UNREACHABLE! => {
#     "changed": false,
#     "msg": "Failed to connect to the host via ssh: ssh: connect to host host1 port 22: Connection timed out",
#     "unreachable": true
# }

In this case, you’d need to check your SSH configuration and network connectivity to host1.

Handling Module Errors

Another common issue is errors with specific Ansible modules. For instance, if you’re trying to use the yum module but you encounter an error, it’s likely that there’s an issue with the module or its dependencies on the node.

ansible-playbook playbook.yml

# Output:
# host1 | FAILED! => {
#     "changed": false,
#     "msg": "The Python 2 bindings for rpm are needed for this module. yum and dnf require python2-rpm.",
#     "rc": 257
# }

In this case, the error message indicates that the yum module requires the python2-rpm package, which is missing from host1. The solution would be to install the missing package.

Best Practices and Optimization

When using Ansible, it’s important to follow best practices to ensure smooth operation and optimal performance.

  • Use a Version Control System: Keeping your Ansible playbooks and other files in a version control system like Git can save you a lot of headaches. It allows you to track changes, rollback to a previous version if something goes wrong, and collaborate more easily with others.

  • Keep Playbooks Simple and Readable: Ansible playbooks should be as simple and readable as possible. Use comments to explain what each part of the playbook does, especially if it’s complex or not immediately obvious.

  • Use Roles and Include Statements: Ansible allows you to organize your playbooks into roles and include other playbooks. This can make your playbooks more manageable and reusable.

  • Test Your Playbooks: Always test your playbooks before running them on production systems. Ansible has a --check option that allows you to run a playbook in ‘dry run’ mode, showing you what changes it would make without actually making them.

By understanding common issues and following best practices, you can make the most of Ansible’s powerful automation capabilities.

The Fundamentals of IT Automation

To fully appreciate Ansible and its capabilities, it’s important to understand the concepts of IT automation and configuration management.

IT Automation: Efficiency at Its Best

IT automation involves using software to create repeatable instructions and processes to replace or reduce human interaction with IT systems. Automation not only saves time and reduces the potential for human error, but it also increases consistency and predictability in your IT operations.

For instance, consider the task of deploying a web server. Without automation, you would need to manually install the web server software, configure it, and start the service on each server. This could be time-consuming and prone to errors, especially if you’re managing a large number of servers.

With automation, you can define these tasks in a script or playbook and run it on all your servers with a single command, saving you considerable time and effort.

Configuration Management: Consistency Across the Board

Configuration management is a subset of IT automation that focuses on maintaining an IT system’s state in a desired, consistent manner. It involves managing the configuration of system resources, services, and software packages.

For example, if you’re managing a cluster of web servers, you’d want to ensure that they all have the same configuration for consistency and predictability. If one server has a different configuration, it could lead to unexpected behavior and make troubleshooting more difficult.

How Ansible Revolutionizes IT Operations

Ansible combines the power of IT automation and configuration management in a simple, easy-to-use package. With Ansible, you can automate complex tasks, ensure consistency across your IT infrastructure, and greatly simplify your IT operations.

Consider our earlier example of deploying a web server. With Ansible, you could define a playbook that automates the entire process:

---
- hosts: webservers
  tasks:
  - name: install apache
    yum:
      name: httpd
      state: latest
  - name: start apache
    service:
      name: httpd
      state: started

This Ansible playbook installs the latest version of Apache (httpd) on all web servers and starts the service. Running this playbook ensures that all your web servers are running the same version of Apache with the same configuration, demonstrating Ansible’s power in IT automation and configuration management.

By understanding the fundamentals of IT automation and configuration management, you can better appreciate the power and utility of Ansible in modern IT operations.

Practical Applications of Ansible

Ansible’s utility goes beyond basic IT tasks. Its flexible design and powerful features make it an ideal tool for managing complex, real-world scenarios.

Managing Large-Scale Cloud Infrastructure

Cloud computing has revolutionized the way we manage IT infrastructure. With Ansible, you can automate the management of your cloud infrastructure, whether it’s AWS, Google Cloud, Azure, or any other cloud platform.

For example, you can use Ansible to automate the creation of EC2 instances on AWS:

---
- hosts: localhost
  gather_facts: False

  tasks:
  - name: Launch instance
    ec2:
      key_name: mykey
      instance_type: t2.micro
      image: ami-0d8f6eb4f641ef691
      wait: yes
      group: webserver
      count: 3
      vpc_subnet_id: subnet-29e63245
      assign_public_ip: yes

In this playbook, we’re using the ec2 module to create three t2.micro instances in the webserver security group, each with a public IP address. This is just a basic example, but you can automate more complex tasks like setting up a load balancer, configuring networking, and more.

Automating Application Deployment

Ansible is also a powerful tool for automating application deployment. With Ansible, you can automate the entire deployment process, ensuring that your application is deployed consistently across all your servers.

For example, you can use Ansible to automate the deployment of a Django application:

---
- hosts: webservers
  tasks:
  - name: ensure django is installed
    pip:
      name: django
      state: latest
  - name: start django project
    django_manage:
      command: startproject mysite
      app_path: /var/www/mysite

In this playbook, we’re using the pip module to ensure that Django is installed, and then the django_manage module to start a new Django project named mysite in the /var/www/mysite directory.

Further Resources for Mastering Ansible

To delve deeper into Ansible and its capabilities, here are some resources that you might find helpful:

Recap: Ansible IT Automation Guide

In this comprehensive guide, we’ve delved into the world of Ansible, a powerful tool for IT automation and configuration management.

We began with the basics, understanding what Ansible is and how it simplifies IT tasks. We then ventured into more advanced territory, exploring Ansible’s key features like idempotency, agentless architecture, and the use of playbooks. We also provided practical examples of Ansible playbooks, demonstrating how they can be used to manage and configure systems.

Along the way, we tackled common challenges you might face when using Ansible, such as connectivity issues and module errors, providing you with solutions and best practices for each issue.

We also compared Ansible with other IT automation tools like Puppet, Chef, and SaltStack, giving you a sense of the broader landscape of tools for IT automation. Here’s a quick comparison of these tools:

ToolEase of UseArchitectureLanguage
AnsibleHighAgentlessYAML
PuppetModerateMaster-AgentPuppet DSL
ChefModerateMaster-AgentRuby
SaltStackHighMaster-MinionYAML

Whether you’re just starting out with Ansible or you’re looking to level up your IT automation skills, we hope this guide has given you a deeper understanding of Ansible and its capabilities.

With its simplicity, ease of learning, and powerful features, Ansible is a formidable tool in the realm of IT automation. Now, you’re well equipped to harness its power. Happy automating!