RHCE 9.0 Practice Exam: Automating Cron Job Scheduling with Ansible

📌 Introduction

In this RHCE 9.0 Ansible exam practice guide, we will automate the configuration of scheduled tasks using the cron module in Ansible. We will set up a cron job that runs every 2 minutes and logs a message using the logger command.

This guide includes:

• How to create a cron job using Ansible
• How to schedule tasks under a specific user account
• How to verify cron job creation
• How to troubleshoot common cron job issues

💡 What You Will Learn

✅ How to create cron jobs using Ansible
✅ How to run scheduled tasks under a specific user
✅ How to verify cron job execution using crontab -l
✅ How to troubleshoot cron job issues

📜 1. Task Requirements

📍 1.1. Problem Statement

1. Create an Ansible playbook named /home/greg/ansible/cron.yml.
2. Run the playbook on the test host group.
3. Schedule a cron job that runs every 2 minutes.
4. The cron job must run as user natasha.
5. Verify that the cron job is created successfully.

The cron job should execute the following command:

logger "EX200 in progress"

📜 2. Writing the Ansible Playbook

📍 2.1. Create the Playbook File

$ vim /home/greg/ansible/cron.yml

📄 Playbook Breakdown (Step-by-Step)

---
- name: Configure Cron Job for User Natasha
  hosts: test
  become: yes
  tasks:
    - name: Ensure cron job is present
      ansible.builtin.cron:
        name: "EX200 Logging Job"
        minute: "*/2"
        job: 'logger "EX200 in progress"'
        user: natasha

📌 Explanation:

• become: yes → Ensures the playbook runs with elevated privileges.
• ansible.builtin.cron → Manages cron jobs via Ansible.
• name: "EX200 Logging Job" → Identifies the cron job.
• minute: "*/2" → Runs every 2 minutes.
• job: 'logger "EX200 in progress"' → Logs a message to system logs.
• user: natasha → Runs the cron job as user natasha.

📜 3. Running the Playbook

$ ansible-navigator run /home/greg/ansible/cron.yml -m stdout

📌 Expected Output

PLAY [Configure Cron Job for User Natasha] ****************************************

TASK [Ensure cron job is present] ************************************************
changed: [node2]

PLAY RECAP ************************************************************************
node2  : ok=1 changed=1 unreachable=0 failed=0

✅ The cron job has been successfully created for user natasha.

📜 4. Verifying Cron Job Creation

$ ansible test -a 'crontab -l -u natasha'

📌 Expected Output

node2 | CHANGED | rc=0 >>
#Ansible: EX200 Logging Job
*/2 * * * * logger "EX200 in progress"

✅ This confirms that the cron job is correctly added to the crontab of user natasha.

📜 5. Checking Cron Job Execution

Since the cron job logs messages to the system log, verify execution using:

$ ansible test -a 'tail -n 5 /var/log/messages'

📌 Expected Output (Varies by system)

node2 | CHANGED | rc=0 >>
Feb 19 14:02:01 node2 natasha[1234]: EX200 in progress
Feb 19 14:04:01 node2 natasha[1235]: EX200 in progress
Feb 19 14:06:01 node2 natasha[1236]: EX200 in progress

✅ Every 2 minutes, a new log entry should appear.

📜 6. Common Issues & Troubleshooting

🔴 Issue 1: Cron Job Not Appearing in crontab -l

✅ Solution:

If the cron job is missing, rerun the playbook with --force-handlers:

$ ansible-playbook /home/greg/ansible/cron.yml --force-handlers

Ensure the user exists:

$ ansible test -m shell -a 'id natasha'

🔴 Issue 2: Cron Job Not Executing

✅ Solution:

Restart the cron service:

$ ansible test -m service -a 'name=crond state=restarted'

Check if the cron service is running:

$ ansible test -a 'systemctl status crond'

🔴 Issue 3: Logs Not Appearing in /var/log/messages

✅ Solution:

If rsyslog is disabled, enable it:

$ ansible test -m service -a 'name=rsyslog state=started enabled=yes'

Check system logs manually:

$ ansible test -a 'journalctl -u crond --no-pager'

📜 7. Summary

• Created an Ansible playbook (cron.yml) to configure a cron job.
• Configured a cron job that runs every 2 minutes for user natasha.
• Verified that the cron job exists using crontab -l.
• Checked execution logs using tail /var/log/messages.
• Troubleshot common cron job issues.

🚀 Congratulations! You have successfully automated cron job scheduling with Ansible for RHCE 9.0! 🚀
📢 If you found this guide helpful, share it with your RHCE 9.0 study group! 📢

🔥 Good luck on your RHCE 9.0 exam! 🔥