【IT Notes】RHCE測驗補充題 Create and use partitions

Create /home/student/ansible/partition.yml, which will create partitions on managed nodes:

•  After sdb creating a 1500M primary partition, partition number 1, and format ext4
•  All groups to permanently mount the partition to /data
•  If there is not enough disk space, give prompt information  

"Could not create partition of that size"

•  create 800M partition
•  If sdb does not exist, a prompt message will be given 

"This disk is not exist"

【題前說明】

這題的做法很類似於第九題，只不過後者是建立邏輯卷宗，而這題是做磁碟切割，難度來說一樣，要會使用不常用的module，首先對每台node的sdb磁區切割出1500MB空間，並將磁區編號命名為1、檔案格式為ext4，根目錄上建立/data資料夾並掛載到sdb1，若磁碟空間不足，要輸出「Could not create partition of that size」的訊息，並將磁區空間分割降為800MB。若完全不存在sdb磁區則是直接輸出「this disk is not exist」。

一．解題過程：

[student@workstation ansible]$ vim partition.yml

---
- name: create new partition
  hosts: all
  tasks:
    - name: create new partition
      block:
        - name: create 1500MiB partition
          parted:
            device: /dev/sdb
            number: 1
            state: present
            part_end: 1500MiB
        - name: format filesystem
          filesystem:
            fstype: ext4
            dev: /dev/sdb1
      rescue:
        - name: output error msg
          debug:
            msg: "Could not create partiontion of that size"
        - name: create 800MiB partition
          parted:
            device: /dev/sdb
            number: 1
            state: present
            part_end: 800MiB
      always:
        - name: create directory data
          file:
            path: /data
            state: directory
        - name: mount data on device
          mount:
            src: /dev/sdb1
            path: /data
            state: mounted
            fstype: ext4
      when: ansible_devices.sdb is defined
    - name: output error msg
      debug:
          msg: "This disk is not exist"
      when: ansible_devices.sdb is not defined

二．驗證結果

[student@workstation ansible]$ ansible-playbook -C partition.yml

紅色警告是因為dry run沒有真切割，所以這是正常訊息

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

正式跑就都一切正常

[student@workstation ansible]$ ansible all -m shell -a 'df -h'

輸入指令來檢查每台node所分割的新磁區

三．恢復解題前的環境

[student@workstation ansible]$ vim 19-lab-parted-stop.yml

---
- name: remove parted
  hosts: all
  tasks:
    - name: remove directory
      block:
        - name: unmount /data
          mount:
            path: /data
            state: unmounted
        - name: remove directory
          file:
            path: /data
            state: absent
          
    - name: remove parted
      block:
        - name: remove parted
          parted:
            device: /dev/sdb
            number: 1
            state: absent

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

[student@workstation ansible]$ ansible-playbook 19-lab-parted-stop.yml

最後這題補充題沒有考出來，不過有做練習就一樣放上來，個人感覺實用性不高，很少人會用ansible部署的方式來分割磁區，總之，這段時間所做的練習和紀錄可告一段落了，想想這過程真的很漫長，從開始上課到今天完成所有RHCE筆記，中間經歷過三年時間，當然只是我自己偷懶，其實應該要從RHCSA就開始做筆記了，不過光是RHCE就總共練習了快要20題，這樣寫下來還真是累人，後面的路程還很漫長，還是那句老話，再接再厲吧！