Introduction in one sentence: Ansible is an open-source automation tool that helps you manage servers in bulk, deploy applications, and execute tasks, making repetitive work automated, repeatable, and error-free.
1. What is Ansible?
Ansible is an IT automation tool written in Python, used for:
·Configuration Management: Bulk modification of system configurations (e.g., adding users, installing software, etc.)
·Application Deployment: One command to deploy across all servers simultaneously
·Task Execution: Execute shell commands in bulk
·Orchestration: Define the order and conditions of task execution to achieve complex deployment processes
Unlike other automation tools (like Puppet, Chef), Ansible does not require a client to be installed on the managed nodes (Agentless); as long as you can connect via SSH, you can manage directly.
2. Advantages of Ansible
1.Simple and easy to learn: Configuration files use YAML format, with clear and readable syntax, resulting in low learning costs.
2.No client agent: No need to install additional software on managed nodes, reducing maintenance costs.
3.Cross-platform: Supports Linux, Unix, macOS, Windows (requires WinRM support), and even network devices.
4.Rich modules: Thousands of built-in modules covering scenarios like software installation, file management, user management, and network device management.
5.Extensible: If the built-in modules are insufficient, you can write custom modules in Python.
3. Core Concepts
|
Concept |
Explanation |
|
Control Node |
The machine running Ansible commands, usually your management machine |
|
Managed Node |
The server being managed |
|
Inventory |
Defines the list of hosts to be managed, which can be grouped |
|
Module |
The smallest functional unit executed by Ansible, such as yum to install software, copy to copy files |
|
Task |
A specific invocation of a module |
|
Playbook |
A script composed of multiple tasks, written in YAML |
|
Role |
A way to organize Playbooks for easier reuse and division of labor |
4. Installing Ansible
Ansible runs on the Control Node, and the Managed Node only needs to have SSH open.
1. Install on CentOS / RHEL
sudo yum install epel-release -ysudo yum install ansible -y
2. Install on Ubuntu / Debian
sudo apt updatesudo apt install ansible -y
3. Install using pip (cross-platform)
pip install ansible
After installation, verify the version:
ansible–version
5. Configuring the Inventory
The default Inventory file path:
/etc/ansible/hosts
Example:
[webservers]192.168.1.101192.168.1.102[dbservers]192.168.1.103
6. Testing the Connection
Ensure that the Control Node can SSH login to the Managed Node without a password (it is recommended to use ssh-keygen + ssh-copy-id to configure public key login), then execute:
ansible all -m ping
If it returns pong, the connection is normal.
7. Your First Ansible Command
For example, to check the uptime of servers in bulk:
ansible webservers -m shell -a“uptime”
·webservers: Target host group
·-m shell: Use the shell module
·-a: Module parameters
8. Summary and Next Article Preview
In this article, we completed:
·Understanding Ansible’s functions and advantages
·Mastering core concepts
·Installing and configuring Ansible
·Testing and executing the first command
In the next article “Ad-hoc Commands and Common Modules”, we will learn how to execute tasks in bulk from the command line and familiarize ourselves with the usage of common modules to greatly enhance your server management efficiency.
💡 Tip: It is recommended to practice with simple commands like ansible all -m ping and ansible all -m shell -a “command” before learning Playbooks.
