【IT Notes】RHCE測驗第十三題 Generate a hardware report

 Create a playbook called /home/student/ansible/hwreport.yml that produces an output file called /root/hwreport.txt on all managed nodes with the following information:

• Inventory host name

• Total memory in MB

• BIOS version

• Size of disk device sda

• Size of disk device sdb

• Each line of the output file contains a single key=value pair.

Your playbook should:

• Download the file from http://example.classroom.com/cd/exam_rhce8/hwreport.empty and save it as /root/hwreport.txt

• Modify /root/hwreport.txt with the correct values

• If a hardware item does not exist, the associated value should be set to NONE

【題前說明】

這是會用到大量變數概念的題目，解法也很多種，我學的只是一種比較懶惰的寫法，分數可能不高，但仍可以達到題目所要求的結果。首先要去data主機上下載hwreport.empty檔到本地的/root底下，將檔名改成hwreport.txt，檔案裡面的參數很重要，要依照裡面的參數來編輯ansible用部署的變數。基本的邏輯是：key去讀取hwreport.txt裡面的所對應文字當標題，並當作變數的參照；value根據ansible facts去每一台node抓取資料會來當值，並放置到所對應的key後面，若沒有找到相對應的值則輸出NONE。敘述這段好像在繞口令，這題也是我在練習時花免多時間去理解的，難度大概可以排名前三。

一．解題過程：

[student@workstation ansible]$ wget http://example.classroom.com/cd/exam_rhce8/hwreport.empty

\\可以先把hwreport.empty下載下來看裡面的內容

[student@workstation ansible]$ cat hwreport.empty

# Hardware report
HOST=inventoryhostname
MEMORY=memory_in_MB
BIOS=BIOS_version
DISK_SIZE_SDA=disk_sda_size
DISK_SIZE_SDB=disk_sdb_size

[student@workstation ansible]$ vim hwreport.yml

---
- name: create hwreport
  hosts: all
  vars:
    hw:
      - hw_key: HOST
        hw_value: "{{ ansible_hostname | default('NONE',true) }}"
      - hw_key: MEMORY
        hw_value: "{{ ansible_memtotal_mb | default('NONE',true) }}"
      - hw_key: BIOS
        hw_value: "{{ ansible_bios_version | default('NONE',true) }}"
      - hw_key: DISK_SIZE_SDA
        hw_value: "{{ ansible_devices.sda.size | default('NONE',true) }}"
      - hw_key: DISK_SIZE_SDB
        hw_value: "{{ ansible_devices.sdb.size | default('NONE',true) }}"
  tasks:
    - name: fetch hwreport
      get_url:
        url: http://example.classroom.com/cd/exam_rhce8/hwreport.empty
        dest: /root/hwreport.txt
    - name: modify content
      lineinfile:
        path: /root/hwreport.txt
        regexp: "^{{ item.hw_key }}"
        line: "{{ item.hw_key}}={{ item.hw_value }}"
      loop: "{{ hw }}"

二．驗證結果

[student@workstation ansible]$ ansible-playbook -C hwreport.yml　　\\試跑看看

看到紅色是正常的，因為試跑而已沒有部署成功，自然不會有檔案產生

[student@workstation ansible]$ ansible-playbook  hwreport.yml

正式跑完就就會出現黃色的change值

[student@workstation ansible]$ ansible all -m shell -a 'sudo cat /root/hwreport.txt'

驗證看看是否每一台node都有抓到檔案

三．恢復解題前的環境

[student@workstation ansible]$ vim 13-lab-hwreport-stop.yml

---
- name: remove hwreport file
  hosts: all
  tasks:
    - name: remove hwreport file
      file:
        path: /root/hwreport.txt
        state: absent

- name: remove hwreport.yml
  hosts: 127.0.0.1
  tasks:
    - name: remove hwrepot.yml
      file:
        path: /home/student/ansible/hwreport.yml
        state: absent
    - name: remove hwreport.empty
      file:
        path: /home/student/ansible/hwreport.empty
        state: absent

[student@workstation ansible]$ ansible-play 13-lab-hwreport-stop.yml