Master Ansible: From Basics to Advanced Automation for Ops Teams

1. Basics

The future of operations relies on traditional industries leveraging cloud and AI to process big data, requiring increasingly sophisticated automation tools to deliver value in minutes rather than days.

1.1 Definition

Automation aims to run repetitive tasks automatically without human intervention. Ansible is a key tool that helps achieve this by providing modules for software deployment, configuration, management, CI/CD, and zero‑downtime upgrades.

System layer: Linux, Windows

Virtualization: VMWare, Docker, OpenStack

Commercial hardware: F5, ASA

System applications: Apache, Zabbix, RabbitMQ, SVN, GIT

1.2 Why Choose Ansible

Python‑based, low learning curve for operators

Rich built‑in modules and commercial extensions

Decentralized configuration migration

Agentless: no client setup required

1.3 Working Principle

Ansible has no client; it uses SSH on Linux and PowerShell on Windows. The control node authenticates, pushes modules to targets, executes them, and cleans up temporary files.

Ansible workflow involves four roles:

Users (via CMDB, API, Ad‑Hoc, or playbooks)

Ansible command line

Inventory (host list)

Modules, plugins, and API

1.4 Communication Method

Since Ansible 1.3 the default is OpenSSH (Linux) and PowerShell (Windows). Authentication can be password or SSH key based.

1.5 Installation

# Install Python
yum install python-pip python-devel -y
# Install gcc and development tools
yum install gcc glibc-devel zlib-devel rpm-build openssl-devel -y
# Upgrade pip
pip install --upgrade pip
# Install Ansible
pip install ansible --upgrade
# Verify installation
ansible --version

Alternatively, use the system package manager:

yum install ansible -y

1.6 Directory Structure

Run rpm -ql ansible to view the layout:

Configuration files: /etc/ansible/ Executable binaries: /usr/bin/ansible‑* Python libraries: /usr/lib/pythonX.X/site‑packages/ansible/ Documentation:

/usr/share/doc/ansible‑*/

1.7 Configuration File Details

The main config file is /etc/ansible/ansible.cfg. Important sections include:

defaults : basic settings such as forks, timeout, and fact gathering.

privilege_escalation : sudo configuration for non‑root users.

ssh_connection : SSH arguments, control path, and pipelining.

accelerate : optional acceleration daemon settings.

colors : output color customization.

1.8 Common Ansible Commands

Executable files reside in /usr/bin/. Key commands: ansible: run ad‑hoc tasks on hosts. ansible-doc: view module documentation. ansible-galaxy: manage roles from Ansible Galaxy. ansible-playbook: execute playbooks. ansible-vault: encrypt/decrypt sensitive data.

Example of checking host reachability:

ansible all -m win_ping

1.9 Inventory Configuration

The inventory file ( /etc/ansible/hosts by default) defines hosts and groups in INI style. Hosts can be listed by IP or hostname, with optional port numbers. Groups are declared in brackets, and a host can belong to multiple groups.

# Example inventory
[webservers]
web1.magedu.com http_port=808 maxRequestsPerchild=801
web[10:20].magedu.com

[dbservers]
db-a.magedu.com

db-[b:f].magedu.com

[webservers:children]
apache
nginx

[webservers:vars]
ntp_server=ntp.magedu.com

2. Two Common Command Sets

2.1 Ad‑Hoc Commands

Ad‑Hoc commands are one‑off operations executed directly from the command line. Syntax:

ansible <host-pattern> -m <module> -a <arguments>

Typical options include -i for inventory, -f for parallelism, -u for remote user, and -k to prompt for SSH password.

Examples:

Check if hosts are alive: ansible linux -m ping Run a command on all hosts: ansible linux -m command -a 'hostname' List hosts in a group:

ansible linux --list-hosts

2.2 Playbooks

Playbooks are YAML files that define a series of tasks to be applied to groups of hosts, providing a reusable and version‑controlled automation workflow.

Playbooks are executed with ansible-playbook <playbook.yml> and can include variables, handlers, and roles for complex deployments.

2.3 Additional Tools

ansible-galaxy

: install and manage reusable roles. ansible-vault: encrypt sensitive variables and files.