The following are a few tips and tricks to get ready and make good use your time and tooling available.
The exam will last for 2 hours, it gives you a 6 min per question, some questions represents only 2% or 3% of the total exam score. Avoid spending too much time on low scoring questions, if you get stuck in one of these, skip to the next one and leave these to be completed at the end.
I've notice experienced people fail the exam on first attempt, people who work with kubernetes on daily basis, mainly because the test covers quite a few different scenarios we don't usually interact with everyday.
People whith over 1 year of experience will likely pass the test withtout much difficulties, to avoid falling on the same trap, you should try some exercises to review your skills on all areas required by the exam to not be caught by surprise.
If you have a short experience with kubernetes, reading the docs is the best starting point, but it is a tedious and long task and does not point you to right direction, the resources provided here try to give you some directions, you should also try the exercises multiple times and get prepared for the exam.
To make best use of your time, you should avoid typing the yaml files by hand, it is a tyme consuming task and there are better way of doing it.
The first is using the cli kubectl with the flags --dry-run -o yaml to generate the yaml file for you, the example below will output the yaml to the terminal:
kubectl run nginx --image=nginx --dry-run=client -o yaml
The following is a list of tools you should be familiar when working with kubernetes. Knowing the basics of these tools will save you some time during the exam and also on daily activities.
Bash is the default shell in most linux distros, the VM running the test will have it, making good use of the shell is the first priority for anyone working with kubernetes.
Alias:
Aliases are very useful to save time with commands that are done really often, in the exam, you will type the kubectl command many times, the command itself is not long, but savind some time is valuable given the short. The command can be aliased to:
alias k=kubectl
Every time you need to use kubectl you can just type k, e.g:
kubect get pods
k get pods
Shortcuts:
CTRL + R -> bash history search
CTRL + Z -> Send active program to background
fg -> Restore suspended program (or fg %2)
jobs -> list background jobs
kubectl is the cli used to interact with Kubernetes api. This is the tool you must master to pass the test without pressure.
Make sure you are using the cli based on same version of your exam. To get the cli version use the following command: kubectl version
In case you don't want to use the defaul editor while modifying resources e.g. kubectl edit pod nginx. You can change the default editor by changing the environment variable KUBE_EDITOR:
export KUBE_EDITOR=nano
kubectl edit pod nginx <-- Will open nano as defaul editor
Vim is powerfull text editor used by defaul when editing resources via command kubectl edit. Knowing how to leave it(:q!) and save the changes(:wq) is the first thing you should know.
Setup
vi ~/.vimrc
# then add these two lines to the file
set tabstop=2
set expandtab # use spaces for tabs
In case you already know the basics, the following shortcuts will help you save some time:
Mode switch
i -> Enter into insert mode
ESC -> exit inset mode (command mode)
While on command mode (ESC)
:wq -> Save and Close file, or ZZ
:q! -> quite wihtout saving
:qa! -> Close all files, abandon changes
ZZ -> Save and exit
dd -> Delete current line
dG -> Deletes contents from cursor positio to end of file
vim cheatsheet will give you all shortcuts needed if you want to go beyond the basics.
If VIM is too advanced for your, nano might simplify the things, knowing the following shortcuts will save you some time:
^representsCTRLon Windows and Linux, orCommandon Mac
^S -> Save current file
^X -> Exit from nano
if nano is your default editor, edit the resource using kubectl edit pod nginx then make the desired changes, then CTRL+S CTRL+X to save, exit and apply the changes.
nano cheatsheet will give you all shortcuts needed to master nano.
grep is a Linux/UNIX command to search for text PATTERNS in a FILE or INPUT. When a match is found, grep prints to the terminal each line matching the pattern.
Usage:
Search for the work hello in the file filename.txt
grep 'hello' filename.txt
grep -i 'hello' filename.txt (case insensitive)
grep -R 'hello' . (all files on current and subfolders)
grep -v 'hello' filename.txt (lines without hello)
grep -B 4 'hello' filename.txt (include 4 lines before matched line)
grep -A 4 'hello' filename.txt (include 4 lines after matched line)
cat filename.txt | grep -i 'helo' (input from previous command)
Example:
kubectl get pods | grep -vi running (show only pods not running containing)
The cat (“concatenate“) is one of the most used commands in Linux/Unix. cat allows us to create a single view of one or multiple files and output the result to the terminal or to a file.
Display the contents of a file in the terminal.
cat file.txt
Display the contents of multiple files in the terminal.
cat file1.txt file2.txt
If the content of the file is too big, use more or less to paginate the contents.
cat longfile.txt | more (forwarard only)
cat longfile.txt | less (scroll up and down)
Create/Replace a file with contents from stdin (press CTRL+D to save).
cat > file.txt
Append to a file the contents from stdin (press CTRL+D to save).
cat >> file.txt
Allow multiple lines of input to a file until EOF is found.
$ cat <<EOF > file.txt
> a
> b
> c
> EOF
Multiline input to a variable
$ sql=$(cat <<EOF
SELECT foo, bar FROM db
WHERE foo='baz'
EOF
)
tmux is a terminal multiplexer. It lets you switch easily between several programs in one terminal, detach them (they keep running in the background) and reattach them to a different terminal. It is useful when you have a limited access to only one shell like in the exam terminal.
^representsCTRLon Windows and Linux, orCommandon Mac
tmux -> start new session
^B -> enter on command mode
While on command mode:
c -> create console
n -> next window
w -> window list (selector)
& -> kill window
split panel
% -> vertical split
" -> horizontal split
x -> kill pane
UP, DOWN-> Switch pane
* * * * * command to execute
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│ ┌───────────── hour (0 - 23)
│ │ ┌───────────── day of the month (1 - 31)
│ │ │ ┌───────────── month (1 - 12)
│ │ │ │ ┌───────────── day of the week (0 - 6)
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* * * * * command to execute
day of the week (0 - 6) (Sunday to Saturday; 7 is also Sunday on some systems)