How I Passed the LFCS Exam: Real Advice from My Second Attempt

Tips, tools, and what I wish I’d done differently before going to the exam

You’ve heard it right: I did not pass on the first attempt, and that’s OK!

If you’re preparing for the LFCS (Linux Foundation Certified System Administrator) exam, you’ve probably already heard a lot of generic advice like: “know your basics,” “practice a lot”. That’s fine, but I wanted to write something more practical and personal: what actually worked for me.

This post is not sponsored, just my honest experience and what helped me pass the LFCS.

Start with KodeKloud

First: do all the KodeKloud mock exams. They’re incredibly helpful for simulating the exam environment, especially if you’re not used to CLI-based tasks under pressure.

Use Killer.sh Wisely

Once you purchase the LFCS, you get two free accesses to Killer.sh

Use only one Killer.sh session before your actual exam.

And make sure you do it at least twice, you can reset the same session and retake it to reinforce what you’ve learned.

Why save one?
If you don’t pass the LFCS on your first try (which happens!), you get a free retake, and with it you have another Killer.sh session. Having a fresh one after your first attempt can give you a huge confidence boost for the second round.

Know Your Weaknesses

Everyone has weak spots. Here were mine, and I recommend you focus heavily on them:

1. iptables

There was a heavy question around iptables, and trust me—if you don’t know how to set up basic rules, it can cost you the exam.
Practice until writing rules from scratch in CLI feels natural. Know how to:

• Block and allow ports
• Set up basic NAT and forwarding
• Save and restore rules

2. Storage (LVM, Disks, Mounting)

You need to understand the flow from physical disks to logical volumes:

• Create partitions
• Format them
• Mount them
• Extend volumes and resize filesystems

Get Comfortable with VIM

During the exam, you’ll need to edit config files fast. Here’s what I used most often:

• /word — search for a word
• :set nu — show line numbers
• :30 — jump to line 30
• Shift + $ — end of current line
• Shift + G — end of file
• g — beginning of file

If you’re not fluent in VIM, take a few hours to get comfortable. It will save you a lot of stress during the test.

Schedule Your Exam for the Morning

If you can, take the exam first thing in the morning.
Your brain is fresh
You’re less likely to be distracted
Energy and focus are high

Always Check Which Host You’re On

I made a mistake here in my first attempt: I completed one or two questions on the wrong host.
Result? Zero points.

The exam setup I had included 17 questions and 17 machines — one per task. So every time you move to a new question, double-check your SSH target. Seriously.

Use apropos

Forget a command or tool? Don’t panic.
Just use:

apropos "selinux"

It’ll return a list of related commands. You can also try:

man -k selinux

This helped me identify the tools I needed.

Don’t Rush. You Have Two Chances

The best advice I can give? Take your time learning.

The LFCS exam is a hands-on, real-world admin challenge. If you fail the first time, it’s okay. You get a free second attempt, and you’ll be better prepared for it.

Use your first run as a benchmark if needed. Learn from your mistakes. Come back stronger.

Good luck! You’ve got this.
And if you’re just starting your DevOps journey, LFCS is a solid first milestone.

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