【IT Notes】RHCE測驗第一題 INSTALL AND CONFIGURE ANSIBLE

Install and configure Ansible on the control node workstation.example.com as follows:

• Install the required packages

• Create a static inventory file called /home/student/ansible/inventory so that:

  • node1 is a member of the dev host group
  • node2 is a member of the test host group
  • node3 and node4 are members of the prod host group
  • node5 is a member of the balancers host group
  • The prod group is a member of the webservers host group

• Create a configuration file called /home/student/ansible/ansible.cfg so that:

  • The host inventory file is /home/student/ansible/inventory
  • The default content collections directory is /home/student/ansible/mycollections
  • The default roles directory is /home/student/ansible/roles

【題前說明】
 第一題只是很單純地依題目要求把環境和路徑都先設定好，唯一不同於上一個版本的地方就是多了mycollections的設定，這會影響到第三題和後面很多會用到roles的題目，記得當時寫解題的時候我把config檔內的mycollections路徑打錯了，因為卡住幾分鐘的時間被迫回頭檢查兩次後才發現，當時也算是冒了一點冷汗。

一．解題過程：

1.下載並安裝ansible

[student@workstation ~]sudo dnf install ansible-core -y

2.建立檔案資料夾

[student@workstation ~]$ mkdir ansible
[student@workstation ~]$ cd ansible/
[student@workstation ansible]$ touch inventory
[student@workstation ansible]$ mkdir mycollections
[student@workstation ansible]$ mkdir roles

3.依題目要求建立inventory

[student@workstation ansible]$ vim inventory

[dev]
node1

[test]
node2

[prod]
node3
node4

[balancers]
node5

[webservers:children]
prod

用ping模組驗證看看是否都連線成功

[student@workstation ansible]$ ansible all -m ping 

都綠色的回應就是成功了

4.建立ansible.cfg（以前舊版的ansible有範本可以直接複製，但RHCE9之後只能用背的）

[student@workstation ansible]$ vim ansible.cfg

[defaults]
inventory = /home/student/ansible/inventory
roles_path = /home/student/ansible/roles
collections_paths = /home/student/ansible/mycollections 
\\這是考RHCE9和8最大不同之處，8版並沒有這一個設定，所以也是很容易遺忘的重點，collection沒有設定的話後面題目就沒得做了
remote_user = student
ask_passwd = False

[privilege_escalation]
become= True
become_method = sudo
become_user = root
become_passwd = False

二．恢復解題前的環境

為了要反覆練習，我在每一題都做了一個yml，可以讓環境恢復到解題以前的情況。例如本次題目的還原yml命名為 01-lab-config-stop.yml，這裡面移除ansible和所有的設定檔。

[student@workstation ansible]$ vim 01-lab-config-stop.yml

---
- name: remove epel-release and ansible
  hosts: 127.0.0.1
  tasks:
    - name: remove epel-release and ansible-core
      yum:
        name: "{{ item }}"
        state: absent
      loop:
      - epel-release
      - ansible-core
- name: remove config and inventory
  hosts: 127.0.0.1
  tasks:
    - name: remove config, inventory and mycollections
      shell:
              'for i in {ansible.cfg,inventory,mycollections}
                   do
                      rm -rf ~/ansible/$i
                   done'

[student@workstation ansible]$ ansible-playbook 01-lab-config-stop.yml