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Thu Kha Kyawe
Thu Kha Kyawe

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10.Linux Services

Lab Information

As per details shared by the development team, the new application release has some dependencies on the back end. There are some packages/services that need to be installed on all app servers under Stratos Datacenter. As per requirements please perform the following steps:

a. Install postfix package on all the application servers.

b. Once installed, make sure it is enabled to start during boot.


Lab Solutions

🧭 Part 1: Lab Step-by-Step Guidelines

Objective

On all Nautilus App Servers, you must:

Install the postfix package

Ensure the postfix service starts automatically on boot

Target servers:

Server User
stapp01 tony
stapp02 steve
stapp03 banner

1️⃣ Login to Jump Host

ssh thor@jump_host.stratos.xfusioncorp.com
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Password

mjolnir123

2️⃣ Configure App Server 1

SSH to the server:

ssh tony@stapp01
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Password

Ir0nM@n

Install postfix:

sudo yum install -y postfix

# Enable service at boot:

sudo systemctl enable postfix

# (Optional verify)

systemctl status postfix

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exit

3️⃣ Configure App Server 2

SSH:

ssh steve@stapp02
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Password

Am3ric@

Run:

sudo yum install -y postfix
sudo systemctl enable postfix
systemctl status postfix
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exit

4️⃣ Configure App Server 3

SSH:

ssh banner@stapp03
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Password

BigGr33n

Run:

sudo yum install -y postfix
sudo systemctl enable postfix
systemctl status postfix
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🧠 Part 2: Simple Step-by-Step Explanation (Beginner Friendly)

What this lab is testing

This lab checks two Linux administration skills:

Task Command
Install package yum install
Enable service at boot systemctl enable

What is Postfix?

Postfix is a mail transfer agent (MTA).

It sends system emails such as:

alerts

logs

cron notifications

monitoring messages

Example system message:

Backup completed successfully

Step A — Install the package

Command:

yum install postfix

This downloads and installs the mail server.

Step B — Enable service at boot

Command:

systemctl enable postfix

This creates a system link so the service starts automatically whenever the server boots.

Example:

Server reboot → postfix starts automatically

Important Difference
Command Purpose
systemctl start postfix start now
systemctl enable postfix start on boot


Resources & Next Steps
📦 Full Code Repository: KodeKloud Learning Labs
📖 More Deep Dives: Whispering Cloud Insights - Read other technical articles
💬 Join Discussion: DEV Community - Share your thoughts and questions
💼 Let's Connect: LinkedIn - I'd love to connect with you

Credits
• All labs are from: KodeKloud
• I sincerely appreciate your provision of these valuable resources.

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