RHCE 8/EX294 Exam Practice Question 3 (Creating Playbooks With Relevant Keywords)

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RHCE 8 EX294 exam practice question 3

Question

---

Create a playbook with the name, install.yml in /home/lisa/ansible. The playbook will do the following:

– Execute on managed hosts in the production host group

-install the web services which are; php, httpd, and postgresql.

-start and enable the web services which are; php,httpd, and postgresql. If any of the web services fails to be started and enabled, print the message “one of the services can’t be started and enabled”.

-Turn off EnableSendfile option in the httpd configuration file (/etc/httpd/conf/httpd.conf).

To turn it off, the EnableSendfile option must be set as; (EnableSendfile off). The httpd service must be restarted for changes to take effect.

– add the http and https connections to the firewall rule.

---

The conditions for the tasks to run are as follow:

-The operating system must be Red Hat

-System memory must be greater than 152 mb

---

If you must create a variable file, it should be created with the name, lamp.yml, and in /home/lisa/ansible.

---

This question is based on creating playbook in the RHCE 8/EX294 course on this website. If you have gone through this course, solving this wouldn’t be a problem.

RHCE/EX294 Course

Creating and managing Ansible Playbook

Managing Ansible handlers

Using Ansible Loops

Answer

1. Create the playbook, install.yml

*change directory to ansible

[lisa@drdev1 ~]$ cd /home/lisa/ansible

*create the playbook

[lisa@drdev1 ansible]$ vim install.yml

---
- name: Install packages
  hosts: production
  vars:
    webpackages:
     - httpd
     - php
     - postgresql
  tasks:
    - name: install web packages
      yum:
        name: "{{ item }}"
        state: present
      loop: "{{ webpackages }}"
      when: ansible_distribution == "RedHat" and  ansible_memtotal_mb > 152

    - name: start and enable web service
      block:
        - name: start and enable web service only
          service:
             name: "{{ item }}"
             state: started
             enabled: yes
          loop: "{{ webpackages }}"
          when: ansible_distribution == "RedHat" and ansible_memtotal_mb > 152

      rescue:
        - name: debug configuration error
          debug:
              msg: "one of the services can't be started and enabled"

    - name: edit httpd configuration file
      replace:
        path: /etc/httpd/conf/httpd.conf
        regexp: 'EnableSendfile on'
        replace: 'EnableSendfile off'
        backup: yes
      notify: restart httpd

    - name: Add services to firewall
      firewalld:
        service: "{{ item }}"
        permanent: true
        immediate: true
        state: enabled
      loop:
        - https
        - http

  handlers:
    - name: restart httpd
      service:
        name: httpd
        state: started

NOTE: It is advisable you always use handlers at the end of tasks in a play because handlers always execute at the end of a play. Other tasks after the handlers may not execute. It is most times also advisable you use the force_handlers keyword because handlers will ONLY execute if the task calling the handlers results in a changed state.

You can always click on the links just before the answers above to know more about a specific topic if you are not very familiar with the topics. You can also use the practice questions video version where a lot are explained verbally.

You should also know that the end game is for these tasks to run as the question required, hence, you don’t have to write this playbook just exactly as I did. There are other ways this playbook can be written, and some of them are shown at the end of this answer.

We also welcome your ideas and other ways this playbook can be written in the comment section below or click here

by joining other colleagues to learn different ways and ideas.

2. Do a playbook syntax check

[lisa@drdev1 ansible]$ ansible-playbook install.yml --syntax-check

playbook: install.yml

3. Run the playbook.

[lisa@drdev1 ansible]$ ansible-playbook install.yml

PLAY [Install packages] ************************************************************......

4. If you wish, you can verify your configuration.

one of the ways to do this is to verify some or all of the packages installed

[lisa@drdev1 ansible]$ ansible hqdev1.tekneed.com -a 'rpm -q postgresql'

hqdev1.tekneed.com | CHANGED | rc=0 >>
postgresql-10.17-1.module+el8.4.0+11249+895597ab.x86_64

Solution Summary

cd /home/lisa/ansible

vim install.yml

ansible-playbook install.yml –syntax-check

ansible-playbook install.yml

ansible hqdev1.tekneed.com -a ‘rpm -q postgresql’

The playbook can also be written as below

---
- name: Install packages
  hosts: production
  vars:
    webpackages:
     - httpd
     - php
     - postgresql
  tasks:
    - name: install start and enable web services
      block:
        - name: install web packages
          yum:
            name: "{{ webpackages }}"
            state: present

        - name: start and enable web service
          service:
            name: "{{ item }}"
            state: started
            enabled: yes
          loop: "{{ webpackages }}"
      when: ansible_distribution == "RedHat" and ansible_memtotal_mb > 152

      rescue:
        - name: debug configuration error
          debug:
              msg: "one of the services can't be started and enabled"

    - name: edit httpd configuration file
      replace:
        path: /etc/httpd/conf/httpd.conf
        regexp: 'EnableSendfile on'
        replace: 'EnableSendfile off'
        backup: yes
      notify: restart httpd

    - name: Add services to firewall
      firewalld:
        service: "{{ item }}"
        permanent: true
        immediate: true
        state: enabled
      loop:
        - https
        - http

  handlers:
    - name: restart httpd
      service:
        name: httpd
        state: started

You may also decide to create a variable file, lamp.yml and define the variables in there, then create a playbook that will refer to the variable.

*create the variable file

[lisa@drdev1 ansible]$ vim lamp.yml

---
webpackages:
  - httpd
  - php
  - postgresql

mem_value: 152

*create the playbook

[lisa@drdev1 ansible]$ vim install.yml

---
- name: Install packages
  hosts: production
  vars_files: lamp.yml
  tasks:
    - name: install start and enable web services
      block:
        - name: install web packages
          yum:
            name: "{{ webpackages }}"
            state: present

        - name: start and enable web service
          service:
            name: "{{ item }}"
            state: started
            enabled: yes
          loop: "{{ webpackages }}"
      when: ansible_distribution == OS and ansible_memtotal_mb > mem_value

      rescue:
        - name: debug configuration error
          debug:
              msg: "one of the services can't be started and enabled"

    - name: edit httpd configuration file
      replace:
        path: /etc/httpd/conf/httpd.conf
        regexp: 'EnableSendfile on'
        replace: 'EnableSendfile off'
        backup: yes
      notify: restart httpd

    - name: Add services to firewall
      firewalld:
        service: "{{ item }}"
        permanent: true
        immediate: true
        state: enabled
      loop:
        - https
        - http

  handlers:
    - name: restart httpd
      service:
        name: httpd
        state: started

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