Kubectl imperative commands

POD
Create an NGINX Pod

kubectl run –generator=run-pod/v1 nginx –image=nginx

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

kubectl run –generator=run-pod/v1 nginx –image=nginx –dry-run -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 YAML file (-o yaml). Don’t create it(–dry-run) with 4 Replicas (–replicas=4)

kubectl run –generator=deployment/v1beta1 nginx –image=nginx –dry-run –replicas=4 -o yaml

The usage –generator=deployment/v1beta1 is deprecated as of Kubernetes 1.16. The recommended way is to use the kubectl create option instead.

IMPORTANT:

kubectl create deployment does not have a –replicas option. You could first create it and then scale it using the kubectl scale command.

Save it to a file – (If you need to modify or add some other details)

kubectl run –generator=deployment/v1beta1 nginx –image=nginx –dry-run –replicas=4 -o yaml > nginx-deployment.yaml

OR

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

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

Or

kubectl create service clusterip redis –tcp=6379:6379 –dry-run -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 –dry-run -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 -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.

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