Passing the Linux Foundation Certified System Administrator Certification in 2.5 days?

The Linux Foundation Certified System Administrator (LFCS) exam is a respected benchmark for Linux professionals. But what happens when you only have 2.5 days to prepare? That was the challenge I faced when I noticed my LFCS exam voucher was about to expire—while still working full-time.

In this post, I share how I built a focused, time-boxed prep strategy using the KodeKloud LFCS course, ChatGPT, and a Killer.sh practice exam. With roughly 25 hours of available time, I pushed hard to cover all exam topics, identify weak spots, and simulate real testing conditions.

This is not a guide for beginners—but if you already have Linux experience and want to understand what it takes to cram effectively, this story offers real-world insight. I cover mindset, materials, scheduling, and the exam itself—plus tips on what to expect and what to avoid.

# TOC - Table of Contents

• How the story begins
• Pre-Challenge: Background / Experience
• Pre-Challenge: Materials
• Challenge: Mindset
• Challenge: Rules
• Challenge: Schedule
• Challenge: The course
• Challenge: The Killer.sh Session
• Challenge: The Exam
• Post Challenge: The End

# How the story begins

I sat in front of my computer, extremely annoyed. How could I have missed this? - I guess some of us have been exactly in that situation before. I stared at my screen the Linux Foundation Learning Portal open and in front of me. Like a giant red pockmark the open voucher I had bought for the LFCS Exam during the last summer Sale was staring at me. Expiration Date: 7 Days away. I had 2 Options:

1. Let the voucher expire and take the $250 hit.
2. Get exam ready within the remaining time.

The remaining time however was not the 7 days I saw on the screen ... I was heading out with my team for our offsite just 4 days from that fateful moment ... So I had 4 days. A quick look at the times I could schedule the exam (hint: no proctoring slots on Sundays) revealed it was actually 2.5 days. Since my last certification challenge was a couple of years back I decided I was not going to let this go to waste. "I am going to crush this" I thought to myself as my 2 clicks confirmed Saturday at 8PM as my slot for the exam.

# Pre-Challenge: Background / Experience

Looking back I very much didn't come into this as a Linux novice. Here is a quick disclaimer about my background and things that probably made this experience much easier for me than it would be for an absolute beginner:

• Linux Admin: I used to administer Linux servers (mainly Ubuntu) at a small scale for a small company. So I was already familiar with the command-line, the filesystem, simple permissions, basic process management, ...
• Linux/Mac Daily Driver: My daily driver is a Linux machine so I am constantly in contact with Linux and have been for a couple of years.
• VIM User: I already know how to use a fast text editor in my sleep. Including more complex motions, commands and structures.
• CKA Certified: I had already sat a similar exam (same proctoring service, same exam structure) before and passed

# Pre-Challenge: Materials

Here is a list of the materials and content I used to prepare for the exam:

• KodeKloud LFCS Course on Udemy (including labs): This was the primary learning vehicle for me and provided both instructions and labs. More on this later. It's about $15 on Udemy. You can find it here.
• ChatGPT: Yes, yes, AI makes an appearance on this list. I used it to have things explained to me I didn't grasp or that the udemy course was a little light on (later more on this)
• LFCS Official Documentation While boring it always pays to know the rules of the exam you are attempting including weights and question splits between topics.
• Reddit Mostly checking for things somebody who has already taken the exam would know (i.e. is tldr available/installable - spoiler: it is not!)

# Challenge: Mindset

As with most things that are going to create stress - and certifications in particular I find it extraordinarily helpful to get into the right mindset beforehand. Nobody knew I was going to attempt this so I had no external pressure other than the looming exam date and my own expectations of myself. Here are the conscious mindset-shifts I made:

• The money is lost: No sense in crying over spilled milk.
• Failure is a setback, not a game-ender: While annoying even if I fail I will have gained experience that will improve me/my skills.
• Maximum concentration of will: I will commit to putting everything into this I can to succeed.

# Challenge: Rules

Knowing myself and the chaos I am capable of creating for me and everyone around me I decided to institute a couple of rules for this challenge. They were:

1. WorkTime is WorkTime: I am attempting this while also working my 9-5 as a cloud engineer. While Cloudeteer encourages us to take time out of our workday to prep for and take certifications, this experiment needed to happen on too short a notice for me to clear that, so my work for my employer can't suffer from this and those 8hrs a day are off-limits.
2. No more than 10hrs a day of additional study-time: As a former MIT student I have burned the midnight oil a couple of times in the past. Rarely has that had a positive effect on the outcome.
3. No skipping the gym: I think this is self explanatory.
4. Buying time is allowed: If I can spend some money within reason (namely ordering food) I am allowed to do so.
5. Coffee Limit: IT-People burn coffee to produce outcomes but doing that too much will leave me a jittery mess.
6. No less than 6 hrs of Sleep: No sense in ruining my rhythm for this.

# Challenge: Schedule

During the challenge I followed the following basic schedule:

• 05:45 Wake-Up
• 06:00 Gym
• 07:00 Work
• 15:00 Learning

I took meals when I had the time. The schedule was modified on saturday when I didn't have to work.

I did some quick napkin math about how I could split up the topics and came up with the following.

In total I spent 25 hrs on the entire experience (plus the time it took me to write this blogpost)

# Challenge: The course

I had already taken a KodeKloud course before, which helped me a lot with my CKA exam (I passed it on my first try). That course combined clear instruction with hands-on practice in a built-in lab environment. I didn’t need to set up any hardware, and I got instant feedback on my progress. Looking for a similar course for LFCS was a no-brainer and thank god there is one.

As for the course itself I would say there is clouds and sunshine (like in all things).

First for the PROs:

• The course structure is well thought out and extremely well adapted to the testing requirements.
• It was extended with each change to the exam in the past so the content stayed up to date.
• The content was well presented overall.
• The lab interface is clean and works well.
• The Mock Exam is worth it's weight in gold.

And then the CONs:

• The Quality control on the course-videos was somewhat lackluster. Sometimes there were weird sound issues or content was presented and then the same section repeated but now with more polished graphics.
• Older and newer content are very different. While the newer content is very visually pleasing and well thought out with polished dynamic graphics, the older content sometimes appears a bit stale and bland in comparison.
• The Labs were very prescriptive in the way problems were solved. Sometimes there are multiple ways to skin a pig in Linux and the lab would only accept a specific solution or require parameters that were neither best practice nor mentioned in the question.
• QC on Lab multiple choice questions was lacking. I encountered multiple situations where none of the answers were correct or a button just read "answer4"
• Labs were outright missing on some important lectures. The LDAP, timesync, proxy and loadbalancer and most important IPTABLES lectures did not have a lab. This is extremely annoying since these are topics that come up regularly on the LFCS exam.

Some NEUTRALs as well (these are personal preference):

• I watched all the lectures on between 1.25x - 1.5x speed since the presentation felt a bit slow to me otherwise.
• Some labs had 1-2 topics in them that didn't match the lab description. Not terrible just sometimes a bit surprising.

Conclusion: In the end I felt like I was well prepared for the exam and had identified weak areas in my knowledge that needed a little bit of work. The course however taught me a little bit beyond that: While we mostly use google to figure out how to manage commands, write config-files and so much more the exam does not allow that. The course's emphasis on using the man-pages and apropos is really good in preparing you for the meta aspect of the exam and gives an (at least to me) entirely new perspective on how one can go about looking things up along with gaining the practical experience.

# Challenge: The Killer.sh Session

Oh my ... this really was a tough nut to crack. Unlike the Mock Exam I barely finished the 23 tasks it gave me in the allotted 2hrs. The questions were very demanding (long, convoluted, unclear on targets) and really gave me a good kick to the ego. I "passed" (there is no pass/fail grade but I finished above the 67% mark) but by the skin of my teeth. Calling this Exam "A little harder than the actual exam" is the understatement of the century. My actual exam only contained a handful of questions like that. So be aware if you don't score as high on this as you want to on the exam: This is not really a representation of what the exam will be. It is a torture-test with the most difficult content that could be on the exam.

# Challenge: The Exam

The time had come. It was 19:30 and I was sitting in front of my computer ready to get into the exam. Due to my previous experience with the CKA (more on that later) and just general exam anticipation (not really scared just excited) I was a bit jittery ... well I had no reason to be. The Exam was simpler for me than even the mock I had taken in the KodeKloud Course. Another big surprise: My exam environment was stable (thanks PSI) which very much wasn't the case for my CKA which had to be rescheduled due to the session crashing constantly. I also didn't encounter any of the laggyness I had encountered in the past.

And just like that the exam was over and the waiting began. If there is one thing that is annoying about the testing process with the Linux Foundation it would be the grading. You as the test-taker get 0 real-time information apart from a spinner saying "processing" and the general info that it could take up to 24hrs to get your exam scores. Spoiler alert: It takes longer sometimes ... just google "How long does it take to get your {{ lf_exam_name }} scores?". For me it was about 28hrs. Annoying but manageable.

In the end I had passed with a grade of 90%. Good but not perfect. I know which question I bunged up ... let's just say you should do yourself a favor and look at the difference between iptables and nftables and how to persist them.

# Post Challenge: The End

Challenge Complete. This feels good. As somebody who knows the relentless stream of information and learning it takes to complete such a challenge and enjoys it I can tell you: If you feel like this DO IT! But be ready for it will not be easy and you will need to make the time.

What remains (apart from the badge and the warm feeling of success) is these 5 key insights:

1. Time-Boxed Focus Works With a tight deadline and a clear plan, focused effort—even over just 2.5 days—can be highly effective when paired with prior experience.

2. Good Courses Still Need Critical Thinking Even great resources like KodeKloud can have flaws. You must stay sharp, question the material, and fill in gaps yourself.

3. Exam Prep ≠ Real-World Workflow The LFCS restricts internet use, forcing reliance on tools like man and apropos, which shifts how you problem-solve compared to day-to-day sysadmin work.

4. Mock Exams Reveal Blind Spots The KodeKloud mock and especially Killer.sh highlighted knowledge gaps and built mental resilience for the real thing.

5. Health & Routine Matter Protecting sleep, exercise, and mental clarity paid off more than brute-forcing late-night study marathons.