DevOps Mini Concept | Kubernetes imperative commands | Sagar Kakkala's World

English Video for Kubernetes Imperative Commands has been clubbed with Kubernetes Deploymemt Session

For English- Click here amd watch from 48:44 Timestamp

Kubernetes imperative commands are more useful and make your work easier especially when you want to work faster or save time. if you are giving exams like CKA, you must be aware of this to save lot of time.

since we have have used microk8s, let us use alias command or .bashrc file, please do note that if you have updated alias command in .bashrc, we don't need to run alias command everytime we turn on the server

case1: run alias command every time you log into server

alias kubectl="microk8s kubectl"

case2: Update the command in .bashrc file so we don't have to run command every time we login

sudo vi .bashrc

place the command as shown in screenshot

Note: Do not disturb any other contents of the file.

once you placed the command, sign out and sign in to user, you can simply switch to any other user and login to our user for changes to take place

sudo su - root

sudo su - ubuntu

Now lets start with commands, for our practise, we recommend creating seperate namespace first as not to disturb existing resources

kubectl create ns practise

For the pods:

case1: to make pod up directly

kubectl run podname --image=nginx -n practise

In place of podname, you can give any of your desired name, in image, you have to give image that you created or that already exists in dockerhub. i am taking nginx as an image for example, and -n flag stands for namespace

As you can see this command created pod directly, you can verify with this command

kubectl get pods -n practise

case2: To check what command does and not to run any pod

Now if you don't want to run the pods, rather check what does command do, run the command

kubectl run podname --image=nginx -n practise --dry-run=client -o yaml

This does not start the pod, but shows what the command would do

case3: In case you want to edit the file, like manifest file

kubectl run podname --image=nginx -n practise --dry-run=client -o yaml > manifest.yaml

i have taken manifest.yaml as an example you can give any name that you desire

now you can edit the file

sudo vi manifest.yaml

now make the changes that you want to

here i have made changes like podname to podname2 , and image nginx to alpine2.once the changes are done, run the command

kubectl apply -f manifest.yaml

OTHER COMMANDS:

in case you forgot any command, if you had remember first lines of command , you can use help command

kubectl run --help

As you can see this can help you to get with examples

In case the pod is already running and you want to check the detailed information of pod

kubectl describe pod podname -n practise

In case, you want to check the logs of pod,

kubectl logs -f podname -n practise

In case you want to edit the existing pod that is already running,generally below command is not recommended unless we need to make a quick fix

kubectl edit pod podname -n practise

In case, you want to delete the pod

kubectl delete pod podname -n practise

Similarly for Deployment:

 Play with these commands to get real-time practise

kubectl create deployment deploymentname --image=nginx --replicas=2 --port=80 -n practise

Similarly for Service:

kubectl create service clusterip service-name --tcp=8080:80 -n practise

You can play with more commands based on cheat sheet from kubernetes official documentation - click here to navigate

once you are done with practise, delete namespace to delete all your resources at once

To check what is present in your namespace.

kubectl get all -n practise

Now to delete all these resources at once

kubectl delete ns practise

Note: Deleting namespace is never recommended in real-time scenarios

#This concludes our Blog, Happy Learning 😄

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