Harnessing CLI Power: Unleashing Automation with Ansible’s cli_command Module


In the world of automation, the Command Line Interface (CLI) has always played a crucial role. Automation tasks can be executed more quickly and efficiently by utilizing CLI commands. The power of CLI lies in its ability to issue commands in a simple yet effective manner.

This is why it is widely used in IT automation and DevOps scenarios. Ansible is a popular automation tool that provides an easy-to-use interface for managing multiple servers from a central location.

One of the key features that makes Ansible stand out from other automation tools is its cli_command module. This module allows users to execute arbitrary CLI commands on remote systems, enabling them to automate complex tasks that would otherwise be time-consuming or impossible to perform manually.

Explanation of CLI and Its Importance in Automation

The Command Line Interface, or CLI, is a text-based interface used to issue commands directly to a computer’s operating system. It provides a quick and efficient way to interact with systems, especially when compared to graphical user interfaces (GUIs), which can be slow and cumbersome for repetitive tasks.

In the context of automation, the importance of CLI lies in its ability to execute commands quickly and easily across multiple systems simultaneously. This makes it an ideal choice for IT administrators who need to manage large-scale infrastructure environments.

Furthermore, since many DevOps tools are designed around command-line interfaces rather than GUIs, proficiency with these interfaces is often essential for professionals working in this space. Mastery of command-line tools like Ansible’s cli_command module can make complex tasks much more manageable.

An Overview of Ansible’s cli_command Module and Its Benefits

Ansible’s cli_command module allows users to execute any arbitrary command on remote servers using SSH protocol connection options provided by ansible-playbook. It is a versatile and powerful tool that enables automation of complex tasks across a wide range of systems.

By automating routine tasks with Ansible’s cli_command module, IT professionals can save time and be more productive. Additionally, the module allows for greater consistency across infrastructure environments, which can lead to more stable systems and better security posture.

Some of the key benefits of using Ansible’s cli_command module include its ease-of-use, its ability to execute commands remotely, and its flexibility in supporting arbitrary commands. This makes it an ideal choice for anyone looking to automate tasks on multiple servers quickly and efficiently.

Understanding the cli_command Module

Before diving into how to use Ansible’s cli_command module, it’s essential to understand what the module is and how it works. In short, the module enables you to execute command-line interface (CLI) commands on remote machines using Ansible. This means that you can automate tasks that would typically require manual intervention and shorten the time it takes to complete them.

The cli_command module works by sending a CLI command to a remote machine via SSH. The output of that command is then captured and returned to Ansible, where it can be used in subsequent tasks or stored as a variable for later use.

Examples of Commands That Can Be Executed Using the Module

The types of commands that can be executed using the cli_command module are virtually limitless; however, some examples include:

  • Configuration Changes: Use CLI commands to make configuration changes on remote machines without having to physically access them. For example, changing network settings or updating firewall rules.
  • Data Gathering: Use CLI commands to gather information about remote machines, such as disk usage or CPU load. This information can then be used in troubleshooting or reporting.
  • Software Installation: use cli commands to install software on remote machines without having to manually download and install packages individually.

The flexibility of the cli_command module means that you can automate virtually any task that involves executing CLI commands on a remote machine, saving time and reducing errors caused by manual intervention.

The Power of Automation with Ansible’s cli_command Module

Automation is becoming increasingly important in today’s world, where time is a valuable commodity. The ability to automate tasks can save a lot of time and effort, allowing engineers and developers to focus on more critical aspects of their work.

With Ansible’s cli_command module, this task has become much easier. The cli_command module can execute any CLI command on a device remotely.

This means that repetitive tasks such as configuration changes or backups can be automated easily. Automation in this manner leads to increased consistency and accuracy in the network, freeing up time and resources for other vital tasks.

How to Use the Module to Automate Tasks and Save Time

The first step in using Ansible’s cli_command module is installing Ansible itself. Once installed, Ansible offers numerous ways to interact with remote devices through its modules, including the cli_command module.

Before using the module, it is essential first to understand how it works. Once installed and understood, the next step is creating an inventory file that contains the IP addresses or hostnames of all the devices you wish to automate commands on.

The inventory file allows you to group devices logically according to your needs for easy automation. After creating an inventory file and grouping your devices logically, create playbooks that define how these groups should be configured.

A playbook defines what should happen when executed on a group of hosts defined in an inventory file. Using these playbooks allows you to automate your network configurations easily.

Examples of Automation Scenarios Using the Module

One example use case for ansible’s cli_command module could be automating firmware upgrades across multiple switches at once automatically via a single command from one device or terminal as opposed going through each switch manually one by one. Another example scenario could be automating repetitive tasks such as daily backups across all switches in your network to a central repository. Automating these kinds of tasks can save time and reduce errors that may occur when performing them manually.

With Ansible’s cli_command module, the possibilities are endless when it comes to automating tasks in a network. It is an essential tool for engineers and developers who want to save time while increasing consistency and accuracy in their network configurations.

Best Practices for Using Ansible’s cli_command Module

Tips for Optimizing Performance when using the module

Ansible’s cli_command module is a powerful tool that allows you to automate repetitive tasks quickly and efficiently. However, it’s important to optimize performance to ensure that your automation tasks complete as fast as possible. One way to optimize performance is by limiting the number of commands sent to the device.

Sending too many commands at once can overload the device and cause delays. It’s recommended that you use a loop to send commands one-by-one instead.

Another way to optimize performance is by using connection pooling. Connection pooling allows Ansible to reuse open connections instead of opening new ones each time a command is executed.

This saves time and resources, especially when executing multiple commands on the same device. It’s important to limit unnecessary outputs from the device.

The cli_command module retrieves all output from each command executed, which could slow down execution if there are many unnecessary lines in the output. To avoid this, use filters like grep or awk to retrieve only relevant output.

Common Mistakes to Avoid when using the module

When using Ansible’s cli_command module, there are several common mistakes that users make which can lead to errors or inefficient automation workflows. One of these mistakes is not using proper error handling techniques like try-catch blocks or setting failed_when conditions properly when executing commands. This can cause an entire playbook run fail due to a single failed command.

Another common mistake is not validating input before sending it over CLI devices through the cli_command module. For example, sending an incorrect password or mistyping a command could cause issues with devices or even lock you out completely.

It’s important not assume consistency between devices during automation workflows unless there has been prior testing on different models and software versions of those devices used in production. To ensure consistency it’s highly recommended to test using a variety of different devices before automating with the cli_command module.


Optimizing performance, avoiding common mistakes, and validating input are important steps to ensure successful automation workflows. By following these best practices, Ansible’s cli_command module can be a powerful tool in your automation arsenal.

Advanced Techniques for Using Ansible’s cli_command Module

How to use variables and loops with the module

When working with automation, it’s important to be able to use variables and loops to customize your scripts according to specific needs. The cli_command module allows for the use of variables and loops just like any other Ansible module.

To use variables in your cli_command tasks, simply define them in your playbook or inventory file, then reference them in your command as “{{ variable_name }}”. For example, if you want to execute a show command on a router based on its hostname, you could define a variable “router_hostname” in your playbook or inventory file and reference it in your task like so:

“`yaml – name: Execute show command on router

cli_command: command_string: “show run”

provider: host: “{{ router_hostname }}”

username: “{{ username }}” password: “{{ password }}” “`

Similarly, you can use loops with the cli_command module by defining a list of values and looping over them using Ansible’s loop control structure. This allows you to execute the same command on multiple devices at once.

Advanced examples showcasing complex automation scenarios

Here are some advanced examples showcasing how the cli_command module can be used for complex automation scenarios: 1. Configuring network devices automatically based on their current running configurations using regex patterns:

“`yaml – name: Configure routers

hosts: routers tasks:

– name: Backup running config ios_config:

backup: yes – name: Configure ntp servers if not already configured

cli_command: command_string: “show run | include ntp server”

register: output – name: Check if NTP config is present

debug: msg=”{{ item }}”

with_items: “{{ output.stdout_lines }}” when: “‘’ not in item”

– name: Add NTP server cli_command:

command_string: “ntp server” “` 2. Executing a command on a specific router only if the same command hasn’t been executed on that router within the last hour:

“`yaml – name: Execute commands on router if not executed recently

hosts: routers vars:

latest_executed_time: “{{ lookup(‘pipe’, ‘date +%s’) | int }}” tasks:

– name: Check last execution time for command cli_command:

command_string: “show run | include ntp server” register: output

– name : Check whether to execute or not set_fact :

execute : false when : “‘’ in {{ output.stdout }}” and “{{ latest_executed_time }} – {{ lookup(‘file’,’last_execution_time.txt’) | int}} > 3600”

– name : Execute if necessary and log time of execution cli_command:

command_string : “ntp server” register : output

when : execute == true – name : Log execution time

copy : content : “{{ latest_executed_time }}”

dest : “last_execution_time.txt” “` These examples demonstrate how the cli_command module can be used to automate complex tasks using variables, loops, conditionals, and other Ansible features, making it an essential tool for any network automation engineer’s toolkit.


Ansible’s cli_command module is a powerful tool for automating CLI tasks and saving time. By understanding how the module works and best practices for using it, you can unlock its full potential and streamline your workflow. Whether you are an experienced Ansible user or new to automation, this module offers a flexible, efficient way to manage your network devices.

Summary of Key Takeaways from This Article

1. The cli_command module in Ansible allows you to automate tasks on network devices using CLI commands. 2. Understanding how the module works and best practices for its use can help you optimize performance and avoid errors. 3. With the right approach, the cli_command module can offer significant time savings and efficiency gains for network administrators.

Future Developments in CLI Automation with Ansible

The world of network automation is constantly evolving, and Ansible developers are continuing to expand their offerings in this area. One exciting development is the increasing integration of machine learning algorithms into automation workflows, which promises even more sophisticated configuration management capabilities in the future. Additionally, expect to see more support for edge computing devices as they become increasingly common in enterprise networks.

Beyond these technical advancements, there is also a growing recognition of automation as a key driver of business agility and innovation. As organizations seek to keep up with rapid changes in technology and customer demands, automation will increasingly be seen as a critical business enabler rather than simply an IT tool.

Those who master these tools will be well positioned to thrive in an increasingly digital world. In short: by embracing CLI automation tools like Ansible’s cli_command module today, you’re not only improving your day-to-day efficiency – you’re also setting yourself up for success tomorrow!

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