📘 Ansible Learning Journey - From Manual SSH to Automation Thinking

CloudWithHorla | Cloud & DevOps Engineer (Learning in Progress 🚀)

Automation looks simple from the outside — until you try to build it yourself.

Recently, I worked on an Ansible hands-on project as part of my continuous learning in Cloud and DevOps engineering. The goal was simple on paper:

set up a controller node and manage multiple target nodes using Ansible.

This setup mirrors what actually happens in real-world environments — not just labs.

🔧 What I Implemented (Step-by-Step)

1. Provisioned EC2 instances

• 1 controller


• 3 managed nodes

1. Installed core dependencies

• Python3


• Pip


• Ansible on the controller

1. Created Ansible configuration

• Custom ansible.cfg
  


• Inventory file defining all target nodes

1. SSH Key-Based Authentication

• Generated SSH key pair on the controller


• Injected the controller’s public key into each node’s authorized_keys
  


• 
  

  Learned the difference between:
  
  

  
  
  CODE Kopieren

   >>  # append (safe)
  
   >   # overwrite (dangerous)
  
  

  
  
  

You are adding a new line of Public Key which is safe.

echo "ssh-rsa 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 ubuntu@ip-10-0-8-231" >> .ssh/authorized_keys

Caveat: Best practise

You are removing an existing "Public Key" which is not safe.

echo "ssh-rsa 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 ubuntu@ip-10-0-8-231" > .ssh/authorized_keys

Caveat: Not a best practise

Sample

1. Privilege Escalation

• Used become: true for system-level tasks


• Ensured sudo access without breaking security

1. 
   Ansible Ad-Hoc Commands
   

   ansible -m apt -a "name=git state=present" all -b

1. Ansible Playbook Execution

• Installed and removed packages


• Copied files to remote nodes


• Managed services across multiple machines in parallel

📄 Sample Playbook used in my project:

---

- name: Installing nginx playbook

  hosts: all

  become: true

  tasks:

    - name: First Task

      apt:

        name: nginx

        state: absent



    - name: Second Task

      apt:

        name: nginx

        state: present



    - name: Copy file with owner and permissions

      ansible.builtin.copy:

        src: ./index.html

        dest: /var/www/html/index.html

        owner: root

        group: root

        mode: '0777'



    - name: Third Task

      apt:

        name: apache2

        state: present

⚠️ Challenges I Faced (and What I Learned)

1️⃣ “Permission denied (publickey)”

I initially thought Ansible could manage nodes without SSH access.

Through research and troubleshooting, I learned a critical truth:

Ansible always uses SSH. There is no automation without an initial trust path.

Key-based authentication must be established at least once — either at instance creation or manually.

2️⃣ PasswordAuthentication Confusion

I tried disabling password authentication before confirming key-based access.

That was a big lesson:

❌ Disabling PasswordAuthentication does NOT give access

✅ It only removes password login after SSH keys already work

Correct order matters:

1. Establish SSH key access


2. Test connectivity


3. Then disable password authentication

3️⃣ APT Lock Errors (unattended-upgrades)

One node failed while others succeeded.

Cause:

• Ubuntu auto-updates were running in the background

Lesson:

Infrastructure is not deterministic — nodes behave independently.

Solution:

• Wait and retry


• Or design playbooks with retries and checks

Screenshot Output

This is when I ping all the node

This is the second page output of my Playbook

Node 02

• 🔐 Never overwrite authorized_keys
  


• 🛠️ Real learning happens when things break

🌱 Growth Mindset

This project reinforced my core belief:

Never stop learning.

Every error I faced forced me to:

• Research deeper


• Read documentation


• Understand why things work — not just how
  

I’m still learning.

I’m still breaking things.

And I’m still getting better — one tool at a time.

📌 Final Thought

Automation isn’t about avoiding work —

it’s about doing the work once, correctly and at scale.

CloudWithHorla ☁️

Cloud & DevOps Engineer | Always Learning