Managing Remote Servers with Ansible Like a Pro

Configuration management is an important process that is necessary for guaranteeing the integrity and usually includes automation processes. When talking about the servers, configuration management usually relates to the orchestration or IT automation.

In the guide, we will dive deeper into the explanation of the configuration management, its benefits, and also share important recommendations regarding to usage of Ansible tool.

Why Use a Configuration Management Tool

Users can find lots of variants of configuration management tools, and all of them have something unique in terms of complexity and architectural style. Despite some differences, they have the same function. They guarantee that the state of the system is the same as described in the provisioning scripts.

Why should you use configuration management tools? Here are some reasons:

• A possibility to reuse provisioning scripts for various environments such as testing, development, and production.
• Availability of the version control system.
• Sharing of provisioning scripts between the team members for better collaboration.
• Optimized the process of server replication so it will be easier to recover from some errors.

Moreover, such tools help to centralize control over servers, and that can tremendously impact the efficiency level.

Introduction to Ansible

Ansible is one of the popular configuration management tools that helps with simplifying the maintenance and setup of remote servers, so it is possible to run everything quickly.

Ansible provisioning scripts are written in YAML, and this standard is not connected to any specific programming language. That helps to create provisioning scripts more intuitively compared with other similar tools.

Ansible doesn’t need any specific software to be installed on nodes. Ansible software is set up on the main machine, and communication with other nodes is done via SSH.

This tool includes most of the standard features that are available in other tools, and at the same time, offers higher performance standards and simplicity.

Ensuring Consistency with Idempotent Operations

The tool tracks the state of resources so that there won’t be any repeating tasks. In case a specific package was installed, then the tool will restrict the installation of the same tool once again. The system functions in such a way that after every provisioning execution, the desired state is reached. Such behavior is called idempotent, and that means you can check in the playbook whether the task was executed and if there are any changes in the system.

Using Variables, Conditionals, and Loops

When working on the automation scripts, it is possible to use loops, conditions, and variables. By using this option, the process of automation becomes more efficient.

Leveraging System Facts

The tool gathers data about the managed nodes, such as OS and interfaces, and gives it in the global variables that are called system facts. Such facts might be used in playbooks so the automation process can be more adaptive and react based on the provisioned system.

Ansible’s Templating Capabilities

The tool functions on the basis of Jinja2 Python, and it allows access to variables and dynamic expressions. With the use of templates, it is possible to simplify the process of setting up. For example, it is possible to use the template for setting up a virtual host and using the same template for various server installations.

Extensibility Through Modules and Plugins

There is a diversity of built-in plugins and modules that can help with the admin tasks. For instance, it is possible to install packages with apt and synchronize files with rsync. Moreover, it is possible to work with popular database systems such as MongoDB, MySQL, and others. Also, it is possible to add additional modules and plugins in case there is a necessity for custom functionality.

Key Ansible Concepts Explained

Now, let’s review some key concepts to get a better understanding of Ansible and how it functions.

The Control Node: Your Central Command

A control node is where Ansible is installed. There might be several control nodes within the system, and almost any machine can be set up to be a control node, such as a laptop or computer. The only limitation is that the control node cannot be installed on a Windows host. However, this situation can be overcome by using a virtual machine on Linux.  

Target Systems: Managed Nodes

Managed nodes are the systems that are controlled via Ansible. These nodes are reached with the standard SSH and have installed Python 2, 3. Many nodes can function on various OSs, and here Windows is also included.

Organizing Your Infrastructure with Inventory

The inventory file includes a list of managed hosts. Ansible creates a default file during the installation, but you can also have pre-project inventories to separate infrastructure even more, to exclude some possible mistakes. Static inventories are in the form of .ini files. Also, there are dynamic inventories that might be returned to JSON.

Defining Actions with Tasks

A task is a specific part of the work that is done on the managed node. That means every performed action might be called a task. Tasks can be done via ad-hoc commands or may be written in the automation scripts.

Automating Workflows with Playbooks

A playbook is a list of tasks and other directives that are necessary for the host targeting of the automation, privilege escalation, and optional sections. All the tasks are executed sequentially, and the playbook is in YAML format.

Triggering Actions Using Handlers

Handlers are needed for performing such actions as stopping or restarting the service that is running on the managed node. They are usually triggered by tasks, and the execution is done at the end of all the tasks. That means, when several tasks need to be restarted, the restart will be only one at the end of all tasks. The default behavior is the most efficient one, but if there is a necessity, it is possible to have immediate handler execution.

Structuring Automation with Roles

Role is a term that relates to several playbooks, which are organized in a necessary structure. With the help of roles, it is way easier to reuse and repurpose playbooks.

Final Thoughts

Ansible is an awesome automation tool that is great in terms of learning and ease of usage due to YAML for the provisioning scripts. Because of the availability of built-in modules, which are crucial for abstract tasks, users have many more options. This tool is great for all users who need accessible syntax and simplified infrastructure requirements.