others-Must learn skills when preparing for the CKA/CKAD exams

Jul 18, 2020

Purpose

Hi, this post would demo some skills or tricks to pass the CNCF kubernetes CKA/CKAD exams. And It would be also helpful in you daily work even if you don’t want to pass the exam.

Skill #1: Set the kubectl alias

You should set an alias for kubectl command, because this command is the most frequently used command in the exam.

alias k="kubectl"

Then , you can use the k command to execute commands in kubernetes like this:

k get pods
k get nodes -o wide
k scale replicas=2 deployment/testapp
...

Trust me, this alias would save you tons of time in the exam.

Skill #2: Set environment variable for some command options

In the exam, you would likely to input some command options repeatedly, please follow this steps to improve the performance:

If you want to create a resource in kubernetes, but you only want to make a dryrun, and get the yaml template, you can do this command:

k craete deployment testapp --image=nginx --dry-run -o yaml

You would find that the options –dry-run -o yaml would be used more than once, you can define a variable to reuse it in other commands:

export do='--dry-run -o yaml'
kubectl get pod <pod-name> $do

Skill #3: Delete resource quicky by –force option

Normally, if you delete a resource in kubernetes like this:

k delete pod testapp

It would make you wait for a while to safely teardown some other resources. In the exam , it would be not necessary to wait for that, just delete it by force:

k delete pod testapp --force

Skill #4: Create secret by imperative command

Normally, if you create secret in kubernetes with yaml , you would do as follows:

echo -n '1f2d1e2e67df' | base64  #you get MWYyZDFlMmU2N2Rm

Then you create a yaml file to define the secret:

apiVersion: v1
kind: Secret
metadata:
  name: mysecret
type: Opaque
data:
  password: MWYyZDFlMmU2N2Rm

It would cost you a lot of time to do the job, you can use a single command to accomplish the same secret like this:

k create secret generic mysecret —from-literal=password=1f2d1e2e67df

References

You can view some references as follows: