Followers

CKAD - Imperative Commands

While you would be working mostly the declarative way - using definition files, imperative commands can help in getting one-time tasks done ...


While you would be working mostly the declarative way - using definition files, imperative commands can help in getting one-time tasks done quickly, as well as generate a definition template easily. This would help save a considerable amount of time during your exams.

Before we begin, familiarize yourself with the two options that can come in handy while working with the below commands:

--dry-run: By default as soon as the command is run, the resource will be created. If you simply want to test your command, use the --dry-run=client option. This will not create the resource, instead, tell you whether the resource can be created and if your command is right.

-o yaml: This will output the resource definition in YAML format on the screen.


Use the above two in combination to generate a resource definition file quickly, that you can then modify and create resources as required, instead of creating the files from scratch.


POD

Create an NGINX Pod

kubectl run nginx-pod --image nginx

Generate POD Manifest YAML file (-o yaml). Don't create it(--dry-run)

kubectl run nginx --image=nginx --dry-run=client -o yaml


Deployment

Create a deployment

kubectl create deployment --image=nginx nginx


Generate Deployment YAML file (-o yaml). Don't create it(--dry-run)

kubectl create deployment --image=nginx nginx --dry-run -o yaml


Generate Deployment with 4 Replicas

kubectl create deployment nginx --image=nginx --replicas=4


You can also scale a deployment using the kubectl scale command.

kubectl scale deployment nginx --replicas=4


Another way to do this is to save the YAML definition to a file and modify

kubectl create deployment nginx --image=nginx--dry-run=client -o yaml > nginx-deployment.yaml


You can then update the YAML file with the replicas or any other field before creating the deployment.


Service

Create a Service named redis-service of type ClusterIP to expose pod redis on port 6379

kubectl expose pod redis --port=6379 --name redis-service --dry-run=client -o yaml

(This will automatically use the pod's labels as selectors)

Or

kubectl create service clusterip redis --tcp=6379:6379 --dry-run=client -o yaml (This will not use the pods labels as selectors, instead it will assume selectors as app=redis. You cannot pass in selectors as an option. So it does not work very well if your pod has a different label set. So generate the file and modify the selectors before creating the service)


Create a Service named nginx of type NodePort to expose pod nginx's port 80 on port 30080 on the nodes:

kubectl expose pod nginx --port=80 --name nginx-service --type=NodePort --dry-run=client -o yaml

(This will automatically use the pod's labels as selectors, but you cannot specify the node port. You have to generate a definition file and then add the node port in manually before creating the service with the pod.)

Or

kubectl create service nodeport nginx --tcp=80:80 --node-port=30080 --dry-run=client -o yaml

(This will not use the pods labels as selectors)

Both the above commands have their own challenges. While one of it cannot accept a selector the other cannot accept a node port. I would recommend going with the `kubectl expose` command. If you need to specify a node port, generate a definition file using the same command and manually input the nodeport before creating the service.



COMMENTS

Name

Ansible,6,AWS,1,Azure DevOps,1,Containerization with docker,2,DevOps,2,Docker Quiz,1,Docker Swarm,1,DockerCompose,1,ELK,2,git,2,Jira,1,Kubernetes,1,Kubernetes Quiz,5,SAST DAST Security Testing,1,SDLC Quiz,3,SonarQube,3,Splunk,2,vagrant kubernetes,1,YAML Basics,1,
ltr
item
DevOpsWorld: CKAD - Imperative Commands
CKAD - Imperative Commands
DevOpsWorld
https://www.devopsworld.co.in/2022/07/ckad-imperative-commands.html
https://www.devopsworld.co.in/
https://www.devopsworld.co.in/
https://www.devopsworld.co.in/2022/07/ckad-imperative-commands.html
true
5997357714110665304
UTF-8
Loaded All Posts Not found any posts VIEW ALL Readmore Reply Cancel reply Delete By Home PAGES POSTS View All RECOMMENDED FOR YOU LABEL ARCHIVE SEARCH ALL POSTS Not found any post match with your request Back Home Sunday Monday Tuesday Wednesday Thursday Friday Saturday Sun Mon Tue Wed Thu Fri Sat January February March April May June July August September October November December Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec just now 1 minute ago $$1$$ minutes ago 1 hour ago $$1$$ hours ago Yesterday $$1$$ days ago $$1$$ weeks ago more than 5 weeks ago Followers Follow THIS PREMIUM CONTENT IS LOCKED STEP 1: Share to a social network STEP 2: Click the link on your social network Copy All Code Select All Code All codes were copied to your clipboard Can not copy the codes / texts, please press [CTRL]+[C] (or CMD+C with Mac) to copy Table of Content