Generating Kubernetes Yaml Resources using Imperative Commands

So as I was studying to get my CKAD certificate, I was kind of worried about forgetting yaml definitions for Kubernetes resources during my exam, I accumulated the list below of some commands needed to generate/create K8s resources using Imperative commands, to serve as a reference for me and for anyone who is preparing for the CKAD exam.

Pods:

Create:

kubectl run mypod1 --generator=run-pod/v1 --image nginx

This will create a single Pod named mypod1 with Nginx as an image.

Generate:

kubectl run mypod1 --generator=run-pod/v1 --image nginx --dry-run -o yaml >mypod.yaml

Note the “–dry-run” flag which informs K8s not to create the resource, and the “-o yaml” which output a yaml definition, this will generate a yaml file named mypod.yaml which contains a Pod named mypod1 with the image set to Nginx.

Deployments:

Create:

kubectl create deployment mydeploy --image nginx

This will create a deployment with replicas set to 1, In order to scale this deployment later we can run the following command

kubectl scale deployment mydeploy --replicas 3

This will scale the deployment pods to 3 instances.

Generate:

kubectl create deployment mydeploy --image nginx --dry-run -o yaml> mydeploy1.yaml

This will generate a yaml file named mydeploy1.yaml.

Services:

Create:

kubectl expose deployment mydeploy --type LoadBalancer --name myservice --port 80

this will create a Loadbalancer service named myservice to expose mydeploy on port 80.

Generate:

kubectl expose deployment mydeploy --type LoadBalancer --name myservice --port 80 --dry-run -o yaml>myservice.yaml

ConfigMaps:

Create:

kubectl create configmap mycon1 --from-literal Version=v1 --from-literal Type=FrontEnd

This will create a ConfigMap with the following data:

Version=v1
Type=Frontend

Generate:

kubectl create configmap mycon1 --from-literal Version=v1 --from-literal Type=FrontEnd --dry-run -o yaml > mycon1.yaml

This will only generate the yaml file.

Accessing Pod through Bash/PowerShell:

for Linux Pods:

kubectl exec -it mypod1  — /bin/bash

for Windows Pods:

kubectl exec -it mypod1 powershell

using a similar technique you can create or generate yamls for K8s Resources.

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