Automating Apps and Infrastructure with Ansible

# Cài Ansible trên control node (Fedora/RHEL)

$ sudo dnf install ansible -y

$ ansible --version

ansible [core 2.17.3]

python version = 3.12.5

# Thêm hosts vào /etc/hosts

$ sudo tee -a /etc/hosts <<'EOF'

192.168.122.154 host01

192.168.122.94 host02

192.168.122.189 host03

EOF

# Tạo SSH key pair

$ ssh-keygen -t ed25519

Generating public/private ed25519 key pair.

Enter file: /home/joe/.ssh/id_ed25519: [Enter]

Enter passphrase: [Enter]

# Copy SSH key đến các managed nodes

$ for i in 1 2 3; do ssh-copy-id joe@host0$i; done

Number of key(s) added: 1

Now try logging into the machine, with: "ssh 'joe@host01'"

# Inventory file - nhóm hosts theo mục đích

[webservers]

host01

host02

[dbservers]

host03

[production:children]

webservers

dbservers

[webservers:vars]

http_port=80

ansible_user=joe

$ ansible -i inventory.ini all --list-hosts

hosts (3):

host01

host02

host03

$ ansible -i inventory.ini webservers --list-hosts

hosts (2):

host01

host02

# Ping tất cả hosts

$ ansible -i inventory.ini all -m ping

host01 | SUCCESS => {"changed": false, "ping": "pong"}

host02 | SUCCESS => {"changed": false, "ping": "pong"}

host03 | SUCCESS => {"changed": false, "ping": "pong"}

# Chạy command trên group webservers

$ ansible -i inventory.ini webservers -m command -a "uptime"

host01 | SUCCESS | rc=0 >>

09:15:32 up 2 days, 3:42, 1 user, load average: 0.01, 0.02, 0.00

# Cài package với module dnf (cần become root)

$ ansible -i inventory.ini webservers -m dnf \

-a "name=nginx state=present" --become

host01 | CHANGED => {"changed": true, "msg": "Installed: nginx-1.24.0"}

host02 | CHANGED => {"changed": true, "msg": "Installed: nginx-1.24.0"}

# Xem help cho module copy

$ ansible-doc copy

> ANSIBLE.BUILTIN.COPY (/usr/lib/python3/dist-packages/ansible/...)

The copy module copies a file from local or remote machine...

---

- name

: Deploy Nginx Web Server

hosts

: webservers

become

: yes

vars

:

web_port: 80

web_root: /var/www/html

tasks

:

- name: Install nginx

dnf:

name: nginx

state: latest

- name: Start and enable nginx

service:

name: nginx

state: started

enabled: yes

- name: Copy index.html to web root

copy:

src: files/index.html

dest: "{{ web_root }}/index.html"

owner: root

mode: '0644'

- name: Open firewall for HTTP

firewalld:

service: http

permanent: yes

state: enabled

immediate: yes

- name: Create web developer user

user:

name: webdev

groups: wheel

shell: /bin/bash

create_home: yes

state: present

# Dry run (check mode) - không thay đổi thực tế

$ ansible-playbook -i inventory.ini webserver-playbook.yml --check

# Chạy playbook thực sự

$ ansible-playbook -i inventory.ini webserver-playbook.yml

PLAY [Deploy Nginx Web Server] ***********************

TASK [Gathering Facts] ******* ok: [host01] ok: [host02]

TASK [Install nginx] ********* changed: [host01] changed: [host02]

TASK [Start and enable nginx] changed: [host01] changed: [host02]

TASK [Copy index.html] ******* changed: [host01] changed: [host02]

TASK [Open firewall for HTTP] changed: [host01] changed: [host02]

TASK [Create web developer user] changed: [host01] changed: [host02]

PLAY RECAP ********************************************

host01 : ok=6 changed=5 unreachable=0 failed=0

host02 : ok=6 changed=5 unreachable=0 failed=0

$ ansible-galaxy init roles/nginx

- Role roles/nginx was created successfully

$ tree roles/nginx/

roles/nginx/

├── defaults/ # Default variables

│ └── main.yml

├── files/ # Static files to copy

├── handlers/ # Handler definitions

│ └── main.yml

├── tasks/ # Task definitions

│ └── main.yml

├── templates/ # Jinja2 templates

└── vars/ # Role variables

└── main.yml