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Ansible Level 02 Day 01: Ansible Ping Module Usage

This document outlines the solution for Ansible Level 02 Day 01. The objective is to configure a password-less SSH connection between the Ansible controller (Jump Host) and a managed node (App Server 1) and verify the connection using the Ansible ping module.

Table of Contents

Task Overview

Objective: Establish password-less SSH and test Ansible connectivity. * Controller: Jump Host (User: thor) * Managed Node: App Server 1 (stapp01, User: tony) * Inventory File: /home/thor/ansible/inventory * Action: Run Ansible ping module against App Server 1 to ensure connectivity.

Step-by-Step Solution

1. Generate SSH Key Pair

First, generate an SSH key pair on the Jump Host for the thor user. This key will be used to authenticate with the remote app server without supplying a password.

Command: 

ssh-keygen -t rsa
* Note: Press Enter to accept the default file location (/home/thor/.ssh/id_rsa). Crucially, press Enter twice when prompted for a passphrase to leave it empty. Setting a passphrase will cause Ansible to hang, defeating the purpose of automation.

2. Copy Public Key to App Server 1

Next, copy the generated public key to the target server (stapp01). The default user for App Server 1 is tony.

Command: 

ssh-copy-id tony@stapp01
* Prompt: Type yes when asked if you want to continue connecting. * Password: Enter Ir0nM@n when prompted for tony@stapp01's password.

(Optional) Verify the password-less connection works manually: 

ssh tony@stapp01
# You should be logged in without being asked for a password. Type 'exit' to return to the jump host.

3. Execute Ansible Ping

With the password-less connection successfully established, use the provided inventory file to run the Ansible ping module against stapp01.

Navigate to the directory: 

cd /home/thor/ansible

Run the Ping Command: 

ansible stapp01 -i inventory -m ping

Expected Output: 

stapp01 | SUCCESS => {
    "ansible_facts": {
        "discovered_interpreter_python": "/usr/bin/python3"
    },
    "changed": false,
    "ping": "pong"
}

But I got: 

stapp01 | UNREACHABLE! => {
    "changed": false,
    "msg": "Invalid/incorrect password: Permission denied, please try again.",
    "unreachable": true
}

So then i checked inventory file 

stapp01 ansible_host=172.16.238.10 ansible_ssh_pass=Ir0nM@n
stapp02 ansible_host=172.16.238.11 ansible_ssh_pass=Am3ric@
stapp03 ansible_host=172.16.238.12 ansible_ssh_pass=BigGr33n

# here user is missing so i added user to inventory file
stapp01 ansible_host=172.16.238.10 ansible_user=tony
stapp02 ansible_host=172.16.238.11 ansible_user=tony
stapp03 ansible_host=172.16.238.12 ansible_user=tony

Then i tried to ping again and it worked 

stapp01 | SUCCESS => {
    "ansible_facts": {
        "discovered_interpreter_python": "/usr/bin/python3"
    },
    "changed": false,
    "ping": "pong"
}

Why does this work? Because Ansible needs to know which user to log in as when connecting to the remote host. By default, if you don't specify ansible_user, Ansible will attempt to use the current user (in this case, thor) to connect to stapp01. Since thor does not have access to stapp01, the connection fails with a permission error.

Deep Dive: Ansible Ping Module

Not a Network Ping

The Ansible ping module is fundamentally different from the standard ICMP ping command used in networking. * ICMP Ping: Checks if a machine is reachable on the network level. * Ansible Ping: Logs into the target machine via SSH, verifies valid login credentials (like the SSH key we just set up), and ensures a usable Python interpreter is available on the remote host to execute Ansible modules.

If Ansible returns "ping": "pong", it confirms that the node is 100% ready to receive and execute complex Ansible playbooks.