DEV Community: Lakhan Jindam

My CKAD experience - 2023

Lakhan Jindam — Sun, 26 Mar 2023 13:12:58 +0000

I have passed my CKAD certification, and here is my CKAD badge.

Why Choose to Take the CKAD Exam?

I think it's an important question one should ask before opting in to any exam, not only CKAD. In what way will it benefit you in your career growth?

My reason for taking the CKAD exam is that I was already working on Kubernetes and digging more into it. I stumbled upon this exam, which was recommended by my colleagues, and it felt interesting and different from other exams where I could actually showcase my skills without any kind of separate preparation.

Unlike other exams, this one is different. How is it different?

It's a performance-based exam where you need to perform tasks inside a VM on a Linux terminal with access to only certain URLs in a browser.
It doesn't contain any MCQ type questions similar to AWS certs. All questions are practical, and you need to implement them.
It tests your critical thinking ability. Time is a big constraint here, and questions are decent, but how quickly you understand and respond (terminal skills 🪄) is the key. There might be multiple ways to solve the questions, but you need to solve them in fewer steps. Hence, adopt an imperative way (using k8s commands) to solve questions if applicable.

When I researched the CKAD exam and joined some communities, I learned that the exam is taken by two types of individuals:

Individual X, who are familiar with k8s and are currently using it and also have better hands-on experience on the terminal (Linux/Unix).
Individual Y, who have limited knowledge of k8s but are interested in learning and then eventually take the exam.

For individual X, CKAD exam preparation should not take more than 3 weeks - Why?

They are already using k8s (i.e., familiar with k8s architecture and kubectl commands) and are good with the terminal (vim, bash, Linux commands, etc.). These are the only skills required to pass the CKAD exam, frankly speaking :)

So, the point is, if you are an individual X, don't try to over-prepare just because you see people preparing extensively for it. Most of them are type Y, and you have already been preparing for it every day 😁 - This is what I felt, and it stood correct after giving my exam.

If you are an individual Y who wants to learn and prepare for the CKAD exam, enrolling in the KodeKloud course by Mumshad Mannambeth is a great choice. Personally, I follow this person and his YouTube channel, and I can confidently say that his course is better than any other you will find. You can access the course at https://kodekloud.com/courses/certified-kubernetes-application-developer-ckad/.

PS: I have not taken the above CKAD course since I didn't feel it was required for me, but yes, if anyone wants to, it's worth it!!

Before starting anything, just take a look inside CKAD syllabus and its topics so that you can prepare properly → https://training.linuxfoundation.org/certification/certified-kubernetes-application-developer-ckad/

The above page will provide you with answers to "why you should take CKAD" and "who should take CKAD," which are important :)
Check out the Domains & Competencies section for topic-wise weightage.
Also, please refer to the Exam Tips and FAQs section under Exam Details & Resources, which will give you an overview of how your exam will be held online and what the prerequisites are before starting your exam.
I would have loved to summarize the details, but things keep changing around the exam 😅, so it's better to always refer to the actual documentation and resources, which is what I did.

Changes from Last Year - 2022

So, there have been a few changes around the exam environment.

Exam changed from terminal to PSI bridge secure browser, which provides VNC connection to your remote Ubuntu XFCE desktop interface aka your playground. What actually changed for you?
- Well, you cannot use your personal bookmarks that most of the people curated for k8s exam.
- No dual monitor setup allowed (Major one for me!)
Also, along with new Kubernetes version releases, the exam is updated to use the latest version. (I gave my exam on k8s version v1.26).

To test the new remote desktop UI, you can try this killercoda playground. I was using it most of the time to get used to the exam-like environment for solving questions.

Resources That I Have Referred to for Practicing CKAD Exam

https://github.com/dgkanatsios/CKAD-exercises - This is one of the popular resources and will cover all aspects of CKAD syllabus. Practicing 2-3 times will make you confident!
https://github.com/bmuschko/ckad-crash-course#additional-resources - In case you want more overview or practice a different set of questions, you can refer to this one too.

🚨 Lastly, don't forget that you get 2 free sessions on killer.sh when you purchase CKAD exam from CNCF. It sets an environment similar to a real CKAD exam, but questions are tougher than CKAD exam, which will prepare you in the right way (You can claim that from your Linux foundation portal.)

One thing to note for killer.sh is questions will be very much the same for CKAD|CKA|CKS simulator irrespective of different sessions.
Source: https://killer.sh/faq

If this truly is the case, then it is missing questions on some topics below.

Deprecated API versions
Admission controller
RBAC
Ingress

Due to which real exam was actually a bit tough than killer.sh exam since I got questions from above topics.

Exam Experience

Before Attending Exam

There will be an inspection of your place where you intend to give CKAD exam, so remove anything that categorizes as a non-decorative item like a notebook, phone, tablet, etc.
Make sure you check your rig is compatible with PSI bridge standards - Run your test here https://syscheck.bridge.psiexams.com/ (source: https://docs.linuxfoundation.org/tc-docs/certification/tips-cka-and-ckad)
Be ready with your government IDs or passport for your verification.
No one needs to be there in the room where you are giving the exam; otherwise, the supervisor might not allow you to give the exam.
Internet connection should be good; otherwise, it can be a laggy experience and can cause connection retries in-between. Keep your mobile data hotspot handy in case your WIFI is down.
Lastly, if you are using an external monitor with a laptop setup, make sure your laptop lid is closed; otherwise, the exam environment will detect it, and you cannot proceed unless you close it.
1. And you need an external webcam in this case, make sure your webcam quality is good enough to show a clear face of yours and government IDs aka verification proof docs.

For me, point 5 didn't go as expected. I was prepared and planned to give the exam with an external monitor with an external webcam, but my webcam quality was grainy inside the exam environment due to which my verification docs (you need to show it to your camera) and face were not coming clear. Hence, the supervisor told me to change the setup immediately 💔 😔

PS: switched to my laptop camera, and it went fine. Still not sure if it's the exam environment throttling the quality of the webcam since my webcam is a 1080p FHD.
For folks interested/curious, I am using this webcam.

During Exam

My exam started well with no issues or lag inside the virtual machine, but in-between of my exam, my remote desktop froze, and it was not taking any inputs.
What I did was quickly clicked on reset desktop, which actually will restart your VM (your data is persistent, so chill!) but only concern is my crucial time was draining since the timer is on 💣 - After 2 rounds (in the 1st round, it was still stuck, didn't work) of clicking reset desktop, it started to work 😌 but then I was a little bit behind my planned schedule.
The supervisor is continuously monitoring everything - audio, video, screen sharing and make sure you don't cover your face, whisper, or do any kind of actions else a ping from the supervisor will pop up to ruin your focus mode 🙂 (I got some pings 🔔 for external sounds and actions)
A simple but important thing, make sure you are switching to the current context and namespaces for each question. In case you didn't, even if you solved the question correctly, you lose marks 🙀
Some questions on which my confidence was a bit low summoned to trouble me like Ingress, RBAC, Service Accounts. Apart from these topics, I was prepared for everything, but finally, I was able to partially solve questions on those topics (sigh…)

Conclusion

To clear the CKAD exam with more than 80 or 90 percent, it is important to be proficient with all the tips, tricks, and commands that you have learned, and to practice a lot around each topic.

You don't need to have fast typing speed. Instead, type steadily with decent speed and use command aliases for kubectl, which will save time.

Despite a few setbacks, the overall experience of taking the exam was good, especially since it was my first certification exam.

Best of luck 🍀 to those who are planning and preparing for the CKAD exam!

Also, please share your interesting experiences in the comments section. 😈

Ruby cheatsheet for beginners

Lakhan Jindam — Tue, 06 Apr 2021 15:09:44 +0000

Introduction to ruby:

Ruby is an interpreted, high-level, dynamic, general-purpose, open-source programming language that focuses on simplicity and productivity. It was designed and developed in the mid-1990s by Yukihiro Matsumoto (also known as Matz in the Ruby community) in Japan.

If you guys have already done coding in python, it'll be a bit simpler to understand the semantics of ruby even though under the hood ruby is completely different than python.

First, we will talk about the common and frequently used methods.

1.to_s # converts to a string, returns -> '1'
"1".to_i # converts to integer, returns -> 1
puts (1..2).to_a # range(..) operator can be used to create an array
# to_a method converts it to an array
puts ('a'..'g').to_a # similarly for characters
"1.5".to_i # can you tell what will be the output? returns -> 1

By default to_i method will convert any float value to an integer
To sustain float value you can use

"1.234".to_f # returns -> 1.234

Let's look at some basic arithmetic operations

puts 1+2 # addition, returns 3
puts 2*5 # multiplication, returns 10
puts 4%3 # returns 1
puts 1.22312.floor # rounding the value to lowest returns 1
puts 1.22312.ceil # rounding the value to highest returns 2
puts 3.1223289.round(1) # limiting the decimal point to 1, returns -> 3.1
puts 'Hello, world!'.include?('Hello') # returns boolean value, it's case sensitive!
puts [1,2,3].include?(1) # same can be applied to arrays
puts 1/2 # returns 0, wondering why? 🤔

By default interaction with integer values will return an integer.
In order to return a float value do this

puts 1/2.0 # add a decimal point, returns 0.5 😮

To check the length or size of an array or string
Both methods output the same results, prefer whichever suits you 🙃

'ruby'.size # returns 4
'ruby'.length # Similarly, returns 4

Finally, the last one 😌
To get user input

puts "enter your name:"
name = gets # by default it adds a newline i.e \n at the end
name = gets.chomp # can be used to remove \n

Enough of basic, let's hop onto topic wise cheatsheet

Let's get started with the first topic!

1. Arrays

To instantiate an array in ruby there are few ways to do it.

# method 1, the simplest and most intuitive way of declaring array!
array = [1,2,3]
# method 2, using Array object
array = Array.new()
array1 = Array.new(3) # will create array of size 3
array2 = Array.new(3, "ruby") # ^ and will fill array with value->"ruby"
# for some dynamic values, you can use below
array3 = Array.new(5){|index| index = index * 3} # where index->index value of the array
# for multi-dimensional array you can create using below
array4 = Array.new(3){Array.new(3)} # this will create array of size 3x3 and each value will be "nil"
array5 = Array.new(3,0){Array.new(3,0)} # array of size 3x3 with each value->0

Common methods used for array manipulation

prog_langs= ["ruby", "python", "javascript", "go"]
sorted_prog_langs = prog_langs.sort # returns a new array with sorted values
# If you don't want to return new array and wanna sort existing array instead 
prog_langs.sort! # "!" operator here is very handy and can be used with many methods in ruby to perform in-place operation 👌
# concurrently traverse both arrays
frameworks = ["ruby on rails", "django", "react", "Martini"]
prog_langs.zip(frameworks).each do |lang, framework|
  puts "#{lang} has framework: #{framework}"
end
# pop an element from an array
# by default ruby only pops element from tail of array 
# unlike python you cannot pop element based on index
frameworks.pop() # by default pops last element in array and returns popped element
# to remove element from the head of an array
frameworks.shift # by defaults remove one element from head
frameworks.shift(2) # removes first 2 elements, returns ["ruby on rails", "django"]
frameworks.push("spring") # appends to the array from tail
frameworks << "spring" # another alternative for push
# if arrays consists only of string types can use this format
frameworks = %w[ruby_on_rails django react Martini]

2. Strings

Basic operations on a string which is similar to most languages

# declare and assign a value
string = 'hello, world!'
# Interesting fact, all strings are mutable in ruby this will most likely will change in upcoming ruby versions
# also this assignment can be used to remove space from string
string[6] = '' # each char is has an index including space, removes space from string variable
# concat string
string_1 = 'how are you?'
result = string + '' + string_1 # returns -> 'hello, world! how are you?'
# string literals or interpolation in ruby can be achieved using double quotes("")
language = "ruby"
experience = 3
puts "I have #{experience} years of experience in #{language}"
# interpolation can be done using same double quotes
puts "I have #{experience > 2 ? "good" : "ample"} amount of experience in #{language}"
# returns -> "I have good amount of experience in ruby"
# substitution using gsub method
a = "I have 3 years of experience in ruby"
a.gsub!("ruby", "python") # returns -> "I have nice amount of experience in ruby, "!" for in-place substitution"
a.gsub!(/\d/, 5) # use regex to replace, returns -> "I have 5 years of experience in ruby"
# downcase and upcase a string
language.upcase! # returns -> 'RUBY'
language.downcase! # reutrns -> 'ruby'
# to remove spaces from head and tail of string
b = " hello. "
b.strip # by default space is considered, you can pass your arg
# to check if a string start with a substring
# NOTE: both are case sensitive
c = "Whats your favorite programming language?"
c.start_with?('Whats') # returns -> true
c.end_with?('Language?') # returns -> false

3. Hash

Hash is equivalent to dictionaries in python.
There are various ways to create a Hash in ruby.

hash = Hash.new # will create a empty hash -> {}
hash1 = Hash.new('test') # creates hash of default value 'test'
hash2 = {name:'bob', age:21}
puts hash2 # returns -> {:name=>'bob', :age=>21}
puts hash1[0] # returns 'test', as no value is set yet
# inserting a value
hash['language']='ruby'
hash['designation']='software engineer'
puts hash # returns -> {'language'=>'ruby', 'designation'=>'software engineer'}
# to check a key is present or not
hash.has_key?('language') # returns true
hash.key?('language') # alternative to has_key?
# to delete a key
hash.delete('language') # returns the value of that key
# merging two hashes
hash.merge!(hash2) # merges two hashes and changes are reflected in 'hash' variable
puts hash # returns -> {:name=>'bob', :age=>21, :language=>'ruby', :designation=>'software engineer'}

Some bonus stuff!!

if you want to run terminal commands in ruby

# using backticks you can execute these commands
response = `ssh <user>@<IP> 'cd /some/dir && cat somefile.txt'`

Also if any response is of JSON type

# In order to avoid error while parsing, always do below
response = {"name":"bob","occupation":"Software engineer"}
# ruby will implicitly convert this into hash like below
# {:name=>"bob", :occupation=>"Software engineer"}
puts response["name"] # returns -> 👎 i.e nothing
puts response[:name] # Instead use symbols, returns "bob"

But if you're fetching a response from a machine's logs or from an API, it might be stringified in that case you can use

response = '{"name":"bob","occupation":"Software engineer"}'
# When using JSON.parse it won't convert keys to symbols
final_response = JSON.parse(response)
puts final_response["name"] # returns "bob"