Ansible is a powerful open-source automation tool that simplifies IT infrastructure management. It is widely used for configuration management, application deployment, task automation, and orchestration. Ansible allows you to define your infrastructure as code, making it repeatable, versionable, and easier to manage.

Running Commands on Multiple Servers

One of the core functionalities of Ansible is its ability to execute commands or scripts across a group of servers simultaneously. This is particularly useful for tasks like system updates, service restarts, or gathering information from your entire fleet.

Example: Executing a Shell Command

Below is an example of how to use Ansible to run a shell command on all servers defined in the servers group within your inventory.yml file. This command lists the contents of the /var directory on each target machine.

---
tags: [ orchestration ]
---
# To run a command on multiple instances at once - using `servers` group from `inventory.yml`:
ansible -u ansible -i inventory.yml servers -m shell -a "ls /var"

Key Ansible Concepts

• Playbooks: YAML files that describe the desired state of your systems.
• Inventory: A list of hosts that Ansible manages.
• Modules: The actual units of code that Ansible runs to perform tasks.
• Tasks: A single action to be performed by a module.

Benefits of Ansible

• Simplicity: Uses SSH and requires no agents on managed nodes.
• Efficiency: Automates complex tasks, saving time and reducing errors.
• Scalability: Manages infrastructure from small to very large environments.
• Consistency: Ensures that systems are configured uniformly.

For more in-depth information on Ansible and its capabilities, refer to the official Ansible Documentation.