Master Ansible Automation: Key Features, Setup, and Practical Playbook Commands

Ansible Overview

Official site: https://docs.ansible.com. Ansible is a modern automation and operations tool written in Python, combining advantages of tools like Puppet, Chef, and Fabric to enable bulk system configuration, program deployment, and command execution.

It operates on a modular basis; the core itself does not perform bulk deployment, but the modules it runs provide that capability.

Key Features

Modular: invoke specific modules to complete tasks

Key Python modules: Paramiko, PyYAML, Jinja2 (template engine)

Supports custom modules

Implemented in Python

Simple deployment: agentless, relies on Python and SSH (pre‑installed)

Security: based on OpenSSH

Playbook orchestration support

Idempotent: repeated runs produce the same result

No agent or PKI required

Modules can be written in any programming language

YAML format for task orchestration with rich data structures

Powerful multi‑layer solutions

Lab Environment Preparation

Server Name   IP Address
master        192.168.1.20
node01        192.168.1.21
node02        192.168.1.22

1.0 Configure local /etc/hosts on each node

cat <<EOF >> /etc/hosts
192.168.1.20   master
192.168.1.21   node01
192.168.1.22   node02
EOF

2.0 Install Ansible on the master node

yum -y install ansible

Ansible main configuration (ansible.cfg)

cat /etc/ansible/ansible.cfg
inventory = /etc/ansible/host   # host inventory file
forks = 5                     # concurrency
sudo_user = root              # privilege escalation
remote_port = 22              # SSH port
host_key_checking = False     # skip host key verification
timeout = 10                  # connection timeout
log_path = /var/log/ansible.log
private_key_file = /root/.ssh/id_rsa

Hosts inventory file

Hosts can be grouped by service type (e.g., web, db).

Verify remote operation

2.1 Operate on a host group

ansible web -a "df -h"   # check disk usage for the web group

2.2 Operate on specific hosts within a group

2.3 Operate on all hosts

3.0 Configure password‑less SSH

# Generate key pair
ssh-keygen
# Copy the public key to target hosts
ssh-copy-id [email protected]
ssh-copy-id [email protected]

3.1 Edit the inventory file and test

cat /etc/ansible/hosts

ansible web -a "ls /tmp"

Verification succeeded.

Common Ansible Modules

shell/command – execute shell commands

copy/file – transfer files

yum – manage packages

user – manage users and groups

git – deploy from source control

service – manage services

setup – gather host facts

4.1 Shell module with sudo escalation

# Run on node01 and node02
useradd zhangfan
echo 123456 | passwd --stdin zhangfan
# Configure sudo on node02
vim /etc/sudoers

node01 does not have sudo privileges.

Master test

ansible web -m shell -a 'ls /root' -u zhangfan -k --become --become-user root -K

ansible web \
  -m shell \            # specify module
  -a 'ls /root' \       # command to run
  -u zhangfan -k \      # remote user and prompt for password
  --become --become-user root \  # privilege escalation
  -K                    # prompt for sudo password

4.2 Copy module

ansible web -m copy -a "src=/root/nginx-1.12.tar dest=/tmp" -u root

4.3 File module

ansible web -m file -a "dest=/opt/hello mode=600 state=directory" -u root

File states:

absent – delete

directory – create directory

file – regular file

hard – hard link

link – symbolic link

touch – empty file

Directory creation succeeded.

Delete directory: ansible web -m file -a "dest=/opt/hello state=absent" Create a file:

ansible web -m file -a "dest=/opt/hello mode=755 state=touch"

4.4 Yum module

States: absent (uninstall), present (install).

ansible web -m yum -a 'name=memcached state=present'
ansible web -m yum -a 'name=memcached state=absent'

4.5 User module

ansible web -m user -a "name=lisi password=123.com"
ansible web -m user -a "name=php password=123456 shell=/sbin/nologin"

Delete user:

ansible web -m user -a "name=lisi state=absent"

4.6 Git module

Ensure an empty directory exists first.

ansible web -m git -a "repo=https://github.com/ansible/ansible.git dest=/mnt/ansible"

4.7 Service module

Start nginx service:

ansible web -m service -a "name=nginx state=started"

Enable service at boot:

ansible web -m service -a "name=nginx enabled=true"

4.8 Setup module

Print all gathered facts: ansible web -m setup Get OS family:

ansible web -m setup -a "filter=ansible_os_family*"

Get memory information:

ansible web -m setup -a "filter=ansible_*_mb"