Knowledge

Tuesday, August 19, 2025

Kubernetes part7

Class 91 Kubernetes Part7 August 19th

Kubernetes volumes

Step1: Create Ec2 instance ubuntu 25 GB disk space c7.large

Installations

ubuntu@ip-10-0-0-23:~$ sudo -i

root@ip-10-0-0-23:~# apt update -y

minikuber installafirst need to Install docker

Docker Installation :

root@ip-10-0-0-23:~# apt install docker.io -y

root@ip-10-0-0-23:~# systemctl status docker

Minikube installation:

curl -LO https://github.com/kubernetes/minikube/releases/latest/download/minikube-linux-amd64
sudo install minikube-linux-amd64 /usr/local/bin/minikube && rm minikube-linux-amd64

root@ip-10-0-0-23:~# minikube version

minikube version: v1.36.0

commit: f8f52f5de11fc6ad8244afac475e1d0f96841df1-dirty

root@ip-10-0-0-23:~# ll /usr/local/bin

total 129668

drwxr-xr-x 2 root root 4096 Aug 20 13:44 ./

drwxr-xr-x 10 root root 4096 Jun 10 10:00 ../

-rwxr-xr-x 1 root root 132766301 Aug 20 13:44 minikube*

Start the minikube

root@ip-10-0-0-23:~# minikube start --driver=docker --force

root@ip-10-0-0-23:~# minikube status

minikube

type: Control Plane

host: Running

kubelet: Running

apiserver: Running

kubeconfig: Configured

Installation Kubectl:

https://kubernetes.io/docs/tasks/tools/install-kubectl-linux/

root@ip-10-0-0-23:~# curl -LO "https://dl.k8s.io/release/$(curl -L -s https://dl.k8s.io/release/stable.txt)/bin/linux/amd64/kubectl"

root@ip-10-0-0-23:~# chmod 777 kubectl

root@ip-10-0-0-23:~# mv kubectl /usr/local/bin/

root@ip-10-0-0-23:~# kubectl version

Client Version: v1.33.4

Kustomize Version: v5.6.0

Server Version: v1.33.1

Kubernetes Volumes:

Docker volume: data replicate from one container to another container

pods are ephemeral temporary store

K8’s volume and liveness probes:

Basically these K8’s will works on short living data.So let unveil the power of volumes like emptyDir,HostPath, PV and PVC .
The data is a very important thing for an application. IN K8’s,data is kept for a short time in the applications in the pods/containers.By default the data will no longer available. To overcome this we will use kubernetes volumnes.
But before going into the types of volumes,Let’s understand some facts about pods and containers short live data

Scenario1: multiple container with a pod can share one volume because the volume is attached to pod

Scenario2: If pod deleted container and volume also deleted ,new pod will create using replicate controller and it will create new volume but previous data will loss.

to over come this issue we are using Kubernetes Volumes

Types of Volumes

1.EmptyDir

2.HostPath

3.Persist Volume

4.Persist Volume claim(PVC)

1. Empty Dir

This Volume is user to share the data between multiple containers within a pod instead of the host machine or any master/workernode.

EmptyDir volume is created when the pod is create and it exists as long as a pod

There no data available in the emptydir volume type when it is create for first

Container within the pod can access the other container data. However the mount path can be different for each container

If the containers ger crashed the, that will still persist and can be accessible by other or newly create containers.

Pod:pod is group of container, (for ex:-a pod has one container1 along with one more container default exist helper container we also called sidecar container, log information backup multiple purpose use),so the reason command give below script, once container create it will exit from the container, so that is the reason we give here while loop

Practical: Here below script two containers creating and attach the volume, and mount volume in this path /opt/jenkins, if you are using multiple container ,you need specify any command other wise pod will never create.

Step1:

root@ip-10-0-0-23:~# vi manifest.yaml

root@ip-10-0-0-23:~# cat manifest.yaml

apiVersion: apps/v1

kind: Deployment

metadata:

spec:

replicas: 1

selector:

matchLabels:

app: swiggy

metadata:

labels:

app: swiggy # Must match selector

spec:

containers:

- name: container1

image: nginx

command: ["/bin/bash", "-c", "while true; do echo welcome to DevOps class; sleep 5; done"]

volumeMounts:

- name: myvolume

mountPath: "/opt/jenkins"

ports:

- containerPort: 80

- name: container2

image: nginx

command: ["/bin/bash", "-c", "while true; do echo welcome to DevOps class; sleep 5; done"]

volumeMounts:

- name: myvolume

mountPath: "/etc/docker"

volumes:

- name: myvolume

emptyDir: {}

root@ip-10-0-0-23:~# vi manifest.yaml

root@ip-10-0-0-23:~# kubectl create -f manifest.yaml

deployment.apps/mydepl created

root@ip-10-0-0-23:~# kubectl get pod

NAME READY STATUS RESTARTS AGE

mydepl-5d6645bd5b-qg2g7 2/2 Running 0 12s

Step2: Need to check volume mouted or not

We have taken emptydir volume, so not data exists , just create one file

root@ip-10-0-0-23:~# kubectl exec -it mydepl-5d6645bd5b-qg2g7 -c container1 -- bash

root@mydepl-5d6645bd5b-qg2g7:/# cd /opt/jenkins

root@mydepl-5d6645bd5b-qg2g7:/opt/jenkins# ls

Create some file and directory , it will copy automatically another container:

root@mydepl-5d6645bd5b-qg2g7:/opt/jenkins# touch app.py data.dat conta.pdf

root@mydepl-5d6645bd5b-qg2g7:/opt/jenkins# mkdir tcs infosys

root@mydepl-5d6645bd5b-qg2g7:/opt/jenkins# ls -lrt

total 8

-rw-r--r-- 1 root root 0 Aug 20 14:48 data.dat

-rw-r--r-- 1 root root 0 Aug 20 14:48 conta.pdf

-rw-r--r-- 1 root root 0 Aug 20 14:48 app.py

drwxr-xr-x 2 root root 4096 Aug 20 14:48 tcs

drwxr-xr-x 2 root root 4096 Aug 20 14:48 infosys

Container2 automatically exist

root@ip-10-0-0-23:~# kubectl exec -it mydepl-5d6645bd5b-qg2g7 -c container2 -- bash

root@mydepl-5d6645bd5b-qg2g7:/# cd /etc/docker

root@mydepl-5d6645bd5b-qg2g7:/etc/docker# ls -lrt

total 8

-rw-r--r-- 1 root root 0 Aug 20 14:48 data.dat

-rw-r--r-- 1 root root 0 Aug 20 14:48 conta.pdf

-rw-r--r-- 1 root root 0 Aug 20 14:48 app.py

drwxr-xr-x 2 root root 4096 Aug 20 14:48 tcs

drwxr-xr-x 2 root root 4096 Aug 20 14:48 infosys

Container2 create some files

root@mydepl-5d6645bd5b-qg2g7:/etc/docker# touch jenkis.yaml docker.yaml subbu.txt

root@mydepl-5d6645bd5b-qg2g7:/etc/docker#

exit

command terminated with exit code 130

Container1 file came to automatically

root@ip-10-0-0-23:~# kubectl exec -it mydepl-5d6645bd5b-qg2g7 -c container1 -- bash

root@mydepl-5d6645bd5b-qg2g7:/# cd /opt/jenkins

root@mydepl-5d6645bd5b-qg2g7:/opt/jenkins# ls -lrt

total 8

-rw-r--r-- 1 root root 0 Aug 20 14:48 data.dat

-rw-r--r-- 1 root root 0 Aug 20 14:48 conta.pdf

-rw-r--r-- 1 root root 0 Aug 20 14:48 app.py

drwxr-xr-x 2 root root 4096 Aug 20 14:48 tcs

drwxr-xr-x 2 root root 4096 Aug 20 14:48 infosys

-rw-r--r-- 1 root root 0 Aug 20 14:51 subbu.txt

-rw-r--r-- 1 root root 0 Aug 20 14:51 jenkis.yaml

-rw-r--r-- 1 root root 0 Aug 20 14:51 docker.yaml

Step3: above example until pod running container to container replicate is doing , if pod delete

new pod will create but volume data will loss

--Pod deleted

root@ip-10-0-0-23:~# kubectl delete pod mydepl-5d6645bd5b-qg2g7

pod "mydepl-5d6645bd5b-qg2g7" deleted

-- Automatically new pod created

root@ip-10-0-0-23:~# kubectl get pod

NAME READY STATUS RESTARTS AGE

mydepl-5d6645bd5b-whtr8 2/2 Running 0 56s

--We will inside the container, volume no file exists

root@ip-10-0-0-23:~# kubectl exec -it mydepl-5d6645bd5b-whtr8 -c container1 -- bash

root@mydepl-5d6645bd5b-whtr8:/# cd /opt/jenkins/

root@mydepl-5d6645bd5b-whtr8:/opt/jenkins# ls

root@mydepl-5d6645bd5b-whtr8:/opt/jenkins#

container2 also data missing , we loss the data :

root@ip-10-0-0-23:~# kubectl exec -it mydepl-5d6645bd5b-whtr8 -c container2 -- bash

root@mydepl-5d6645bd5b-whtr8:/# cd /etc/docker

root@mydepl-5d6645bd5b-whtr8:/etc/docker# ls

Not over come the issue We are using Host path

2.HostPath

This volume type is the advanced version of the previous volume type

Emptydir.

In EmptyDirmthe data is stored in the volumes that reside inside the pods only

Where the host machine doesn’t have the data of the pods and containers

Hostpath volume type helps to access the data of the pods or container volumes from the host machine.

Hostpath replicates the data of the volumes on the host machine and if you make the changes from the host machine then the changes will be reflected to the pods volumes(if attached)

Step1: delete existing deployment

root@ip-10-0-0-23:~# kubectl delete deploy mydepl

deployment.apps "mydepl" deleted

Step2: previous manifest file only below line are changed for hostpath

volumes:

- name: myvolume

hostPath:

path: /tmp/mydata/

root@ip-10-0-0-23:~# kubectl create -f manifest.yaml

deployment.apps/mydepl created

Container1 some files are created

root@ip-10-0-0-23:~# kubectl exec -it mydepl-57f4bc8d46-7dkqm -c container1 -- bash

root@mydepl-57f4bc8d46-7dkqm:/# cd /opt/jenkins/

root@mydepl-57f4bc8d46-7dkqm:/opt/jenkins# touch app.py jenkins.yaml java.jvm

root@mydepl-57f4bc8d46-7dkqm:/opt/jenkins# ls

app.py java.jvm jenkins.yaml

Container 2 need to check files came or not

root@ip-10-0-0-23:~# kubectl exec -it mydepl-57f4bc8d46-7dkqm -c container2 -- bash

root@mydepl-57f4bc8d46-7dkqm:/# cd /etc/docker/

root@mydepl-57f4bc8d46-7dkqm:/etc/docker# ls

app.py java.jvm jenkins.yaml

Step2: Delete the pod

root@ip-10-0-0-23:~# kubectl delete pod mydepl-57f4bc8d46-7dkqm

pod "mydepl-57f4bc8d46-7dkqm" deleted

root@ip-10-0-0-23:~# kubectl delete mydepl-57f4bc8d46-7dkqm

error: the server doesn't have a resource type "mydepl-57f4bc8d46-7dkqm"

root@ip-10-0-0-23:~# kubectl delete pod mydepl-57f4bc8d46-7dkqm

pod "mydepl-57f4bc8d46-7dkqm" deleted

root@ip-10-0-0-23:~# kubectl get po

NAME READY STATUS RESTARTS AGE

mydepl-57f4bc8d46-6fgfl 2/2 Running 0 46s

root@ip-10-0-0-23:~# kubectl exec -it mydepl-57f4bc8d46-6fgfl -c container1 -- bash

root@mydepl-57f4bc8d46-6fgfl:/# cd /opt/jenkins/

root@mydepl-57f4bc8d46-6fgfl:/opt/jenkins# ls

app.py java.jvm jenkins.yaml

root@mydepl-57f4bc8d46-6fgfl:/opt/jenkins#

exit

root@ip-10-0-0-23:~# kubectl exec -it mydepl-57f4bc8d46-6fgfl -c container2 -- bash

root@mydepl-57f4bc8d46-6fgfl:/# cd /etc/docker/

root@mydepl-57f4bc8d46-6fgfl:/etc/docker# ls

app.py java.jvm jenkins.yaml

root@mydepl-57f4bc8d46-6fgfl:/etc/docker# touch test nexflex google

root@mydepl-57f4bc8d46-6fgfl:/etc/docker#

exit

root@ip-10-0-0-23:~# kubectl delete pod mydepl-57f4bc8d46-6fgfl

pod "mydepl-57f4bc8d46-6fgfl" deleted

root@ip-10-0-0-23:~# kubectl get pod

NAME READY STATUS RESTARTS AGE

mydepl-57f4bc8d46-jww7m 2/2 Running 0 40s

root@ip-10-0-0-23:~# kubectl exec -it mydepl-57f4bc8d46-jww7m -c container1 -- bash

root@mydepl-57f4bc8d46-jww7m:/# cd /opt/jenkins/

root@mydepl-57f4bc8d46-jww7m:/opt/jenkins# ls

app.py google java.jvm jenkins.yaml nexflex test

Here we did hostpath attached to node, whenevery pod delete it will create and attached volume from hostpath ,for single it will work, but real time we are using multi node, we have attached the hostpath single node,if multi node the pods not not created other node.

If Node deleted ,autoscale node also data will loss to overcome this issue:

PVC

We will store the data in cloud EBS storage for example take 100 GB

Persistent volume (PV-1) 15 GB

Persistent volume (PV-2) 10 GB

Persistent volume (PV-3) 45 GB

We have left 30 GB left it is used for future

Claim persistent volume

I have requirement to Pod creation, i need 13 GB ,for the we have claim that PVC (persistent volume claim) from PV ,PVC will check suitable PV either PV-1 ,PV2m PV-3 here PV1,PV3 suitable

Before pod create we should need create PVC

IF you are trying create Pod with 35 GB ,below case PVC searching for suitable PV there is not space available ,PVC went into pending state and also unable create po.

Step1:
EBS volume need to create ,based on the EBS-id need to create PV

Elastic Block store>Create volume >

my-app volume created

Step2: copy the volumeid vol-08360ae5933a3ef0a

root@ip-10-0-0-23:~# vi pv.yaml

---

apiVersion: v1

kind: PersistentVolume

metadata:

spec:

capacity:

storage: 5Gi

accessModes:

- ReadWriteOnce

awsElasticBlockStore:

volumeID: vol-08360ae5933a3ef0a

fsType: ext4

persistentVolumeReclaimPolicy: Recycle

Step3:

-- it is just warning Create one PV-1

root@ip-10-0-0-23:~# kubectl create -f pv.yaml

Warning: spec.persistentVolumeReclaimPolicy: The Recycle reclaim policy is deprecated. Instead, the recommended approach is to use dynamic provisioning.

persistentvolume/pv-1 created

Step4: Create one more PV-2

root@ip-10-0-0-23:~# vi pv.yaml

root@ip-10-0-0-23:~# cat pv.yaml

---

apiVersion: v1

kind: PersistentVolume

metadata:

spec:

capacity:

storage: 2Gi

accessModes:

- ReadWriteOnce

awsElasticBlockStore:

volumeID: vol-08360ae5933a3ef0a

fsType: ext4

persistentVolumeReclaimPolicy: Recycle

root@ip-10-0-0-23:~# kubectl create -f pv.yaml

Warning: spec.persistentVolumeReclaimPolicy: The Recycle reclaim policy is deprecated. Instead, the recommended approach is to use dynamic provisioning.

persistentvolume/pv-2 created

Step5: list of pv's two pvs created (pv-1,pv-2)

root@ip-10-0-0-23:~# kubectl get pv

root@ip-10-0-0-23:~#

Step6: Now claim the PVC ,write pvc file

root@ip-10-0-0-23:~# vi pvc.yaml

root@ip-10-0-0-23:~# cat pvc.yaml

---

apiVersion: v1

kind: PersistentVolumeClaim

metadata:

spec:

accessModes:

- ReadWriteOnce

resources:

requests:

storage: 3Gi

root@ip-10-0-0-23:~# kubectl create -f pvc.yaml

persistentvolumeclaim/mypvc-1 created

root@ip-10-0-0-23:~# kubectl create -f pvc.yaml

persistentvolumeclaim/mypvc-1 created

root@ip-10-0-0-23:~# kubectl get pvc

--Which we have create the volume

root@ip-10-0-0-23:~# kubectl get pv

we have claimed 3 gib bound

Step7: Now we need to attached this volume(PVC) to po

Delete the existing deployment

root@ip-10-0-0-23:~# kubectl get deploy

NAME READY UP-TO-DATE AVAILABLE AGE

mydepl 1/1 1 1 148m

root@ip-10-0-0-23:~# kubectl delete deploy mydepl

deployment.apps "mydepl" deleted

root@ip-10-0-0-23:~# kubectl get deploy

No resources found in default namespace.

Step8: Create deployment with new volume, only need to change below highlighted lines

root@ip-10-0-0-23:~# vi manifest.yaml

root@ip-10-0-0-23:~# cat manifest.yaml

apiVersion: apps/v1

kind: Deployment

metadata:

spec:

replicas: 1

selector:

matchLabels:

app: swiggy

metadata:

labels:

app: swiggy # Must match selector

spec:

containers:

- name: container1

image: nginx

command: ["/bin/bash", "-c", "while true; do echo welcome to DevOps class; sleep 5; done"]

volumeMounts:

- name: myvolume

mountPath: "/opt/jenkins"

ports:

- containerPort: 80

- name: container2

image: nginx

command: ["/bin/bash", "-c", "while true; do echo welcome to DevOps class; sleep 5; done"]

volumeMounts:

- name: myvolume

mountPath: "/etc/docker"

volumes:

- name: myvolume

persistentVolumeClaim:

claimName: pvc-1

root@ip-10-0-0-23:~# kubectl create -f manifest.yaml

deployment.apps/mydepl created

Step8: Whether pod created or not

root@ip-10-0-0-23:~# kubectl get pod

NAME READY STATUS RESTARTS AGE

mydepl-7b4979dff6-m559p 0/2 Pending 0 47s

To identify the error ,here clearly showing pvc-1 not found ,we have given name PVC mypvc-1

root@ip-10-0-0-23:~# kubectl describe pod mydepl-7b4979dff6-m559p

Events:

Type Reason Age From Message

---- ------ ---- ---- -------

Warning FailedScheduling 2m21s default-scheduler 0/1 nodes are available: persistentvolumeclaim "pvc-1" not found. preemption: 0/1 nodes are available: 1 Preemption is not helpful for scheduling.

Step9: Changed PCV name , after change configuration need to apply

persistentVolumeClaim:

claimName: mypvc-1

root@ip-10-0-0-23:~# kubectl apply -f manifest.yaml

Warning: resource deployments/mydepl is missing the kubectl.kubernetes.io/last-applied-configuration annotation which is required by kubectl apply. kubectl apply should only be used on resources created declaratively by either kubectl create --save-config or kubectl apply. The missing annotation will be patched automatically.

deployment.apps/mydepl configured

Now pod is running state

root@ip-10-0-0-23:~# kubectl get pod

NAME READY STATUS RESTARTS AGE

mydepl-587dc99798-9nr6z 2/2 Running 0 16s

root@ip-10-0-0-23:~# kubectl get pv

root@ip-10-0-0-23:~# kubectl get pvc

NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS VOLUMEATTRIBUTESCLASS AGE

mypvc-1 Bound pvc-8998df85-79c6-4df4-9241-3987bebe8519 3Gi RWO standard <unset> 30m

Step10: Try to go inside the po and create some file and delete the pod

root@ip-10-0-0-23:~# kubectl exec -it mydepl-587dc99798-9nr6z -c container1 -- bash

root@mydepl-587dc99798-9nr6z:/# cd /opt/jenkins/

root@mydepl-587dc99798-9nr6z:/opt/jenkins# ls

Created some dummy file

root@mydepl-587dc99798-9nr6z:/opt/jenkins# touch app.py docker manifest.yaml pv

root@mydepl-587dc99798-9nr6z:/opt/jenkins# ls

app.py docker manifest.yaml pv

Step11: lets delete the po ,new pod created automatically

root@ip-10-0-0-23:~# kubectl get po

NAME READY STATUS RESTARTS AGE

mydepl-587dc99798-9nr6z 2/2 Running 0 8m58s

root@ip-10-0-0-23:~# kubectl delete pod mydepl-587dc99798-9nr6z

pod "mydepl-587dc99798-9nr6z" deleted

root@ip-10-0-0-23:~# kubectl get po

NAME READY STATUS RESTARTS AGE

mydepl-587dc99798-smm8q 2/2 Running 0 58s

-- see here i have went into container2 ,our file are exists

root@ip-10-0-0-23:~# kubectl exec -it mydepl-587dc99798-smm8q -c container2 -- bash

root@mydepl-587dc99798-smm8q:/# cd /etc/docker

root@mydepl-587dc99798-smm8q:/etc/docker# ls

app.py docker manifest.yaml pv

EBS safe and secure the data ever though pod delete and cluster delete or node delete.

Step12: Make sure the after cluster delete need delete EBS volume also

root@ip-10-0-0-23:~# kubectl get -- all

NAME READY STATUS RESTARTS AGE

pod/mydepl-587dc99798-smm8q 2/2 Running 0 7m20s

NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE

service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 4h24m

NAME READY UP-TO-DATE AVAILABLE AGE

deployment.apps/mydepl 1/1 1 1 24m

NAME DESIRED CURRENT READY AGE

replicaset.apps/mydepl-587dc99798 1 1 1 16m

replicaset.apps/mydepl-7b4979dff6 0 0 0 24m

root@ip-10-0-0-23:~# kubectl delete deploy mydepl

deployment.apps "mydepl" deleted

Under standing the Access modes:

Access modes determine how many pods can access a persistent volume(PV) or a persistent volume claim(PVC) simulataneously.There are several access modes that can be set on PV or PVC,inclusing:

ReadWriteOnce:This access mode allows a single pod to read and write to the PV or PVC,this is the most common access mode,and its appropriate for use cases where a single pod needs exclusive access to the storage.

ReadOnlyMany:This access mode allows multiple pods to read from the PV or PVC,but does not allow any of them to write to it.This access mode is useful for cases where many pods need to read the same data,such as when servinf a read-only database.

ReadWritemany:This access mode allow multiple pods to read and write to the PV or PVC simultaneously. This mode is appropriate for use cases where many pods need to read and write to the same data ,such as a distributed file system.

Execute: this access mode allows the pod to execute the data on the PV or PVC but not read or write to it.This mode is useful for use cases where the data is meant to be executed by the pods only, such as application code.

--Thanks

Monday, August 18, 2025

Kubernetes part6

Class 90th Kubernetes Part6 August 18th

Deamonsets and statefulsets :

cluster all are similar(replication cluster,replication sets,deployment,deamonsets,statefulsets)

all are same manifest files

Deamon-set:

It is used to run a copy a pod to each worker node.
It is used to perform some tasks like monitoring, Log collection etc.. that need to run on every node of the cluster.
A DaemonSet ensures that all eligible node run a copy of a pod
When you create daemon set k8s schedule on copy of pod in each node.
If we added new node it will copy the pod automatically to new node.
If I remove on node from cluster the pod in that node also removed
Deleting a daemonset will clean up the pods it created
Daemon-set does not contains replicas,because by default it will create only 1 pod in each node.
Deamon sets will not used for deployments on real-time,it is only to schedule.

cluster(cluster is group of servers,master and worker)

demon-sets :single pods for each instance ,whenevery create new instance automatically pod will created. each worker node we have to install one pod or agent pod will give data to permutes will send to Grafana for dashboard visualize

demon-sets only for monitoring and logging purpose not used for deployment

Practical:

Step1:

[root@ip-10-0-0-28 ~]# aws s3 ls

2025-08-16 16:58:08 ccitpublicbucket16

[root@ip-10-0-0-28 ~]#

[root@ip-10-0-0-28 ~]# export KOPS_STATE_STORE=s3://ccitpublicbucket16

[root@ip-10-0-0-28 ~]# kops create cluster --name kopsclstr.k8s.local --zones eu-west-2b,eu-west-2a --master-count 1 --master-size c7i-flex.large --master-volume-size 20 --node-count 2 --node-size t3.micro --node-volume-size=15 --image=ami-044415bb13eee2391

Cluster configuration has been created.

Suggestions:

* list clusters with: kops get cluster

* edit this cluster with: kops edit cluster kopsclstr.k8s.local

* edit your node instance group: kops edit ig --name=kopsclstr.k8s.local nodes-eu-west-2b

* edit your control-plane instance group: kops edit ig --name=kopsclstr.k8s.local control-plane-eu-west-2b

Finally configure your cluster with: kops update cluster --name kopsclstr.k8s.local --yes --admin

[root@ip-10-0-0-28 ~]# kops update cluster --name kopsclstr.k8s.local --yes --admin

Step2:1.Controlplane/master 2 worker node created successfully

Step3:

[root@ip-10-0-0-28 ~]# kubectl get node

NAME STATUS ROLES AGE VERSION

i-000360c9c71860aa1 Ready node 63s v1.32.4

i-02e7e492877aa8af4 Ready control-plane 3m9s v1.32.4

i-0d56c24033208cb64 Ready node 85s v1.32.4

Step4: Create the pod using manifest file

[root@ip-10-0-0-28 ~]# cat manifest.yaml

apiVersion: apps/v1

kind: DaemonSet

metadata:

spec:

selector:

matchLabels:

app: monitor

metadata:

labels:

app: monitor # Must match selector

spec:

containers:

- name: container1

image: nginx

ports:

- containerPort: 80

[root@ip-10-0-0-28 ~]# kubectl create -f manifest.yaml

daemonset.apps/mydeamon created

See here 2 pods created ,We have two worker nodes

[root@ip-10-0-0-28 ~]# kubectl get pods

NAME READY STATUS RESTARTS AGE

mydeamon-cnp7z 1/1 Running 0 89s

mydeamon-nkr5t 1/1 Running 0 89s

[root@ip-10-0-0-28 ~]# kubectl get pods -w

NAME READY STATUS RESTARTS AGE

mydeamon-cnp7z 0/1 ContainerCreating 0 4s

mydeamon-nkr5t 0/1 ContainerCreating 0 4s

mydeamon-cnp7z 1/1 Running 0 8s

mydeamon-nkr5t 1/1 Running 0 8s

Step5: If you want increase worker nodes, need to edit the cluster

[root@ip-10-0-0-28 ~]# kops get cluster

NAME CLOUD ZONES

kopsclstr.k8s.local aws eu-west-2a,eu-west-2b

Suggestions:

* list clusters with: kops get cluster

This command for worker node to change

* edit this cluster with: kops edit cluster kopsclstr.k8s.local

* edit your node instance group: kops edit ig --name=kopsclstr.k8s.local nodes-eu-west-2b

This command for master to change

* edit your control-plane instance group: kops edit ig --name=kopsclstr.k8s.local control-plane-eu-west-2b

Step6: edit the worker node , here each region eu-west-2b 1 node that is the reason showing in cluster min and max showing 2

[root@ip-10-0-0-28 ~]# kops edit ig --name=kopsclstr.k8s.local nodes-eu-west-2b

Changed from 1 to 2

machineType: t3.micro

maxSize: 2

minSize: 2

After change Cluster update the cluster using below command , after run this command instance

will increase.

[root@ip-10-0-0-28 ~]# kops update cluster --name=kopsclstr.k8s.local --yes --admin

Step7: Three worker nodes

[root@ip-10-0-0-28 ~]# kubectl get node

NAME STATUS ROLES AGE VERSION

i-000360c9c71860aa1 Ready node 15m v1.32.4

i-02e7e492877aa8af4 Ready control-plane 17m v1.32.4

i-05b2188bac81487ec Ready node 40s v1.32.4

i-0d56c24033208cb64 Ready node 15m v1.32.4

See here 1 more pod created automatically ,along with workernode

[root@ip-10-0-0-28 ~]# kubectl get pods

NAME READY STATUS RESTARTS AGE

mydeamon-2tfcp 1/1 Running 0 16m

mydeamon-dzcnl 1/1 Running 0 2m31s

mydeamon-m8p4c 1/1 Running 0 16m

See below each pod attached one node

[root@ip-10-0-0-28 ~]# kubectl get pods -o wide

NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES

mydeamon-2tfcp 1/1 Running 0 19m 100.96.2.76 i-000360c9c71860aa1 <none> <none>

mydeamon-dzcnl 1/1 Running 0 5m37s 100.96.3.238 i-05b2188bac81487ec <none> <none>

mydeamon-m8p4c 1/1 Running 0 19m 100.96.1.112 i-0d56c24033208cb64 <none> <none>

[root@ip-10-0-0-28 ~]#

Note: Control plane pod are not create, only pod will create in worker node only

Step8: reduce the worker node automatically pods also got reduced

[root@ip-10-0-0-28 ~]# kops edit ig --name=kopsclstr.k8s.local nodes-eu-west-2b

[root@ip-10-0-0-28 ~]# kops update cluster --name=kopsclstr.k8s.local --yes --admin

maxSize: 1

minSize: 1

[root@ip-10-0-0-28 ~]# kubectl get pods

NAME READY STATUS RESTARTS AGE

mydeamon-dzcnl 1/1 Running 0 10m

mydeamon-m8p4c 1/1 Running 0 23m

[root@ip-10-0-0-28 ~]# kubectl get nodes

NAME STATUS ROLES AGE VERSION

i-02e7e492877aa8af4 Ready control-plane 28m v1.32.4

i-05b2188bac81487ec Ready node 12m v1.32.4

i-0d56c24033208cb64 Ready node 27m v1.32.4

Statefulsets:

Deployment and statefulset

Deployment is used for application ,statefulset used for database

For ex: Last night I had a call with mobile customer care, and I explained my issue with her and requested to resolve the issue. She asked to stay on call for some time meanwhile the call was dropped due to network issues.

Again I called to same number,but this time another person pick the call.He don’t know what the conversion we had with the first person. Again I had to repeat the details of my problem to the second person,though it is an inconvenience but it still works out

Kubernets deployment suit perfectly here.Let’s assumer you deployed your stateless application as deployment with 10 pod replicas running in multiple worker node.

If pod 1 got terminated from node 1,the new pod will gets replaced on either node2 or node1 or anywhere in the cluster

This is possible because,the stateless application pod1 hasn’t stored any data on worker node1, hence can be easily replace by new pod running on a different worker node 2. If the pod is not storing the data then we called it as STATELESS.

Stateless applications:

It can’t store the data permanently
The word STATELESS means no past data
It depends on non-persistent data means data is removed when Pod,node or cluster is stopped.
Non-persistent mainly used for logging info(ex: system log,container log etc)
In order to avoid this problem,we are using stateful application
A stateless application can be deployed as a set of identical replicas,and each repica can handle incoming requests independently without the need to coordinate with other replicas

For ex:- one worker node has two pods one is application and other one database ,if one pod db deleted

Replicaset it aware to create same node to create delete pod , it going to create another worker node

and also not past data, so we are not used for stateless application for database.

STATEFUL application:

Let’s say want to order some some products in amazon, you added some products to your shopping cart. After you added the books to you shopping cart, If forgot to switch off the stove In kitchen and you closed the web browser hurry. after some time you login the browser , the item should be there in cart

Stateful applications are applications that store data and keep tracking it.

Example of stateful applications:

ALL RDS databases(Mysql,sql)

Elastic search,kafka,mongo DB,redis etc..

Any application that stores data

To get the code for stateful application use this link:

https://github.com/devops0014/ksg-stateful-set-application.git

Application stateless whenevery scalein pod will increase, stateful side whenevery scalein or scaleup previous pod copy and create new pod

Statefulset :First pod is primary pod, remaining pod are secondary pod, primary pod only has read/write permission. remaining pod only read access

Scaledown: in deployment it will delete any pod, but where as stateful set whetevery you have create new pod that is only deleted first.(first in last out)

Deployment :

It will create POD’s with random ID’s

Scale down the Pod’s in random id’s

POD’s are stateless POD’s

We use this for application deployment

Stateful set:

It will create POD’s with sticky ID’s

Scale down the POD’s in reverse order

POD’s are stateful POD’s

We use this for database deployment

Step1:

[root@ip-10-0-0-28 ~]# vi statefulset.yaml

[root@ip-10-0-0-28 ~]# cat statefulset.yaml

---

apiVersion: apps/v1

kind: StatefulSet

metadata:

spec:

replicas: 4

selector:

matchLabels:

app: zamoto

metadata:

labels:

app: zamoto # Must match selector

spec:

containers:

- name: container2

image: shaikmustafa/dm

ports:

- containerPort: 80

As you see here , base first pod copy second will create

[root@ip-10-0-0-28 ~]# kubectl create -f statefulset.yaml

statefulset.apps/mystate created

[root@ip-10-0-0-28 ~]# kubectl get pods -w

NAME READY STATUS RESTARTS AGE

mydeamon-dzcnl 1/1 Running 0 76m

mydeamon-m8p4c 1/1 Running 0 90m

mystate-0 1/1 Running 0 8s

mystate-1 0/1 ContainerCreating 0 1s

mystate-1 1/1 Running 0 7s

mystate-2 0/1 Pending 0 0s

mystate-2 0/1 ContainerCreating 0 0s

mystate-2 1/1 Running 0 3s

mystate-3 0/1 Pending 0 0s

mystate-3 0/1 ContainerCreating 0 0s

mystate-3 1/1 Running 0 3s

Three Pods are created .

[root@ip-10-0-0-28 ~]# kubectl get pods

NAME READY STATUS RESTARTS AGE

mydeamon-dzcnl 1/1 Running 0 78m

mydeamon-m8p4c 1/1 Running 0 91m

mystate-0 1/1 Running 0 102s

mystate-1 1/1 Running 0 95s

mystate-2 1/1 Running 0 88s

mystate-3 1/1 Running 0 85s

Step2: Scaleup see create mystate4 set,

[root@ip-10-0-0-28 ~]# kubectl scale statefulset mystate --replicas=5

statefulset.apps/mystate scaled

[root@ip-10-0-0-28 ~]# kubectl scale statefulset mystate --replicas=5

statefulset.apps/mystate scaled

[root@ip-10-0-0-28 ~]# kubectl get pods -w

NAME READY STATUS RESTARTS AGE

mydeamon-dzcnl 1/1 Running 0 86m

mydeamon-m8p4c 1/1 Running 0 99m

mystate-0 1/1 Running 0 9m28s

mystate-1 1/1 Running 0 9m21s

mystate-2 1/1 Running 0 9m14s

mystate-3 1/1 Running 0 9m11s

mystate-4 0/1 ContainerCreating 0 2s

mystate-4 1/1 Running 0 3s

[root@ip-10-0-0-28 ~]# kubectl get pods

NAME READY STATUS RESTARTS AGE

mydeamon-dzcnl 1/1 Running 0 87m

mydeamon-m8p4c 1/1 Running 0 100m

mystate-0 1/1 Running 0 10m

mystate-1 1/1 Running 0 10m

mystate-2 1/1 Running 0 10m

mystate-3 1/1 Running 0 10m

mystate-4 1/1 Running 0 63s

Step2: Scaledown see here last three was terminated, mystate-0 and mystate-1 exist

[root@ip-10-0-0-28 ~]# kubectl scale statefulset mystate --replicas=2

statefulset.apps/mystate scaled

[root@ip-10-0-0-28 ~]# kubectl get pods -w

NAME READY STATUS RESTARTS AGE

mydeamon-dzcnl 1/1 Running 0 87m

mydeamon-m8p4c 1/1 Running 0 101m

mystate-0 1/1 Running 0 11m

mystate-1 1/1 Running 0 11m

mystate-2 1/1 Terminating 0 11m

mystate-2 0/1 Completed 0 11m

[root@ip-10-0-0-28 ~]# kubectl get pods

NAME READY STATUS RESTARTS AGE

mydeamon-dzcnl 1/1 Running 0 89m

mydeamon-m8p4c 1/1 Running 0 102m

mystate-0 1/1 Running 0 12m

mystate-1 1/1 Running 0 12m

Step3: So far what we have created resource using all below is listed out

pods:

[root@ip-10-0-0-28 ~]# kubectl get all

NAME READY STATUS RESTARTS AGE

pod/mydeamon-dzcnl 1/1 Running 0 92m

pod/mydeamon-m8p4c 1/1 Running 0 106m

pod/mystate-0 1/1 Running 0 15m

pod/mystate-1 1/1 Running 0 15m

Services:

NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE

service/kubernetes ClusterIP 100.64.0.1 <none> 443/TCP 110m

Demon set:

NAME DESIRED CURRENT READY UP-TO-DATE AVAILABLE NODE SELECTOR AGE

daemonset.apps/mydeamon 2 2 2 2 2 <none> 106m

NAME READY AGE

statefulset.apps/mystate 2/2 15m

Step3: deleted,service came by default

[root@ip-10-0-0-28 ~]# kubectl delete ds mydeamon

daemonset.apps "mydeamon" deleted

[root@ip-10-0-0-28 ~]# kubectl delete statefulset mystate

statefulset.apps "mystate" deleted

[root@ip-10-0-0-28 ~]# kubectl get all

NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE

service/kubernetes ClusterIP 100.64.0.1 <none> 443/TCP 113m

Namespaces : Particular about name based cluster to display instead of showing all the pod/service/deployment, resources isolated purpose we use namspaces which means sperate one to other

in Production mini two cluster

Preprod cluster: Dev/test/uat

Prod cluster

so far we create created all resource default cluster namespaces. if you want to create which namespace your resource created.

Below command showing which namespace exists

[root@ip-10-0-0-28 ~]# kubectl get namespace

NAME STATUS AGE

default Active 119m

kube-node-lease Active 119m

kube-public Active 119m

kube-system Active 119m

[root@ip-10-0-0-28 ~]# kubectl get ns

NAME STATUS AGE

default Active 119m

kube-node-lease Active 119m

kube-public Active 119m

kube-system Active 119m

Here ,if you given command kubectl get po if you are in default namespace it will show only default namespace pos, dev namespace pod will not show.

Step1:

If you create any pod, by create by default, in default namespace only see below create one dummy pod

[root@ip-10-0-0-28 ~]# kubectl run pod-1 --image=nginx

pod/pod-1 created

[root@ip-10-0-0-28 ~]# kubectl get pod

NAME READY STATUS RESTARTS AGE

pod-1 1/1 Running 0 21s

[root@ip-10-0-0-28 ~]# kubectl describe pod-1

error: the server doesn't have a resource type "pod-1"

[root@ip-10-0-0-28 ~]# kubectl describe pod pod-1

Name: pod-1

Namespace: default

kube-public: whatevery the pods, in your cluster able to access every one.

Default:

As the name suggests, whenever we create any kubernetes object wuch as pod,replicas,etc it will create in th default namespace.

Kube-system (whet every you have installed sperate it will use this namespace for ex: metrics)

This namespace contains the kubernetes components such as kube-controller-manager,kube-scheduler,kube-dns or other controllers.

Kube-public

This namespace is used to share non-sensititve information that can be viewed by any of the members who are part of the kubernetes cluster

[root@ip-10-0-0-28 ~]# kubectl get all -n kube-system

(any scheduler information it will show)

[root@ip-10-0-0-28 ~]# kubectl get all -n kube-node-lease

No resources found in kube-node-lease namespace.

Step2: Create own namespace

[root@ip-10-0-0-28 ~]# kubectl create ns dev

namespace/dev created

[root@ip-10-0-0-28 ~]# kubectl get ns

NAME STATUS AGE

default Active 141m

dev Active 11s

kube-node-lease Active 141m

kube-public Active 141m

kube-system Active 141m

-- No resource exist for the dev namespace

[root@ip-10-0-0-28 ~]# kubectl get all -n dev

No resources found in dev namespace.

Create one pod with namespace dev

[root@ip-10-0-0-28 ~]# kubectl run pod-2 --image=nginx -n dev

pod/pod-2 created

[root@ip-10-0-0-28 ~]# kubectl get all -n dev

NAME READY STATUS RESTARTS AGE

pod/pod-2 1/1 Running 0 24s

see below default namespace dev pod is not showing, becauase it will create specified dev namespace

[root@ip-10-0-0-28 ~]# kubectl get pod

NAME READY STATUS RESTARTS AGE

pod-1 1/1 Running 0 17m

Step3: Now planning deploy the specific namespace

[root@ip-10-0-0-28 ~]# cat statefulset.yaml

---

apiVersion: apps/v1

kind: Deployment

metadata:

name: myspace

namespace: dev

spec:

replicas: 4

selector:

matchLabels:

app: zamoto

template: # Moved to top-level under spec

metadata:

labels:

app: zamoto # Must match selector

spec:

containers:

- name: container2

image: shaikmustafa/dm

ports:

- containerPort: 80

[root@ip-10-0-0-28 ~]# kubectl create -f statefulset.yaml

deployment.apps/myspace created

See here default Pods are not showing

[root@ip-10-0-0-28 ~]# kubectl get po

NAME READY STATUS RESTARTS AGE

pod-1 1/1 Running 0 25m

with namespace dev 4 replica pod showing

Deployment created in dev

[root@ip-10-0-0-28 ~]# kubectl get deployment -n dev

NAME READY UP-TO-DATE AVAILABLE AGE

myspace 4/4 4 4 2m36s

[root@ip-10-0-0-28 ~]# kubectl get po -n dev

NAME READY STATUS RESTARTS AGE

myspace-7bdfc8c57d-5qvdh 1/1 Running 0 25s

myspace-7bdfc8c57d-bvjtt 1/1 Running 0 25s

myspace-7bdfc8c57d-dpjsn 1/1 Running 0 25s

myspace-7bdfc8c57d-vh796 1/1 Running 0 25s

pod-2 1/1 Running 0 8m59s

using command prompt able give namespace

[root@ip-10-0-0-28 ~]# kubectl create -f statefulset.yaml -n dev

delete the deployment for particular name space dev

[root@ip-10-0-0-28 ~]# kubectl delete deployment myspace -n dev

deployment.apps "myspace" deleted

--no resource exist

[root@ip-10-0-0-28 ~]# kubectl get deployment

No resources found in default namespace.

-- pods also deleted automatically

[root@ip-10-0-0-28 ~]# kubectl get pods -n dev

NAME READY STATUS RESTARTS AGE

pod-2 1/1 Running 0 15m

Step4:

Service also we can create similar way

[root@ip-10-0-0-28 ~]# vi service.yaml

[root@ip-10-0-0-28 ~]# cat service.yaml

---

apiVersion: v1

kind: Service

metadata:

spec:

type: LoadBalancer

selector:

app: zamoto

ports:

- port: 80

targetPort: 80

Step5: See here service create dev namespace

[root@ip-10-0-0-28 ~]# kubectl create -f service.yaml -n dev

service/myservice created

[root@ip-10-0-0-28 ~]# kubectl get svc -n dev

NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE

myservice LoadBalancer 100.67.11.194 ac994ded082174dc5ae84c9e924446b1-69473691.eu-west-2.elb.amazonaws.com 80:30364/TCP 17s

Step6: If you want delete the namespace you need first delete the all resource of the namespace

List of resource in dev namespace

[root@ip-10-0-0-28 ~]# kubectl get all -n dev

NAME READY STATUS RESTARTS AGE

pod/myspace-7bdfc8c57d-b8swm 1/1 Running 0 19s

pod/myspace-7bdfc8c57d-brfd8 1/1 Running 0 19s

pod/myspace-7bdfc8c57d-j4tzx 1/1 Running 0 19s

pod/myspace-7bdfc8c57d-swf7j 1/1 Running 0 19s

pod/pod-2 1/1 Running 0 25m

NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE

service/myservice LoadBalancer 100.67.11.194 ac994ded082174dc5ae84c9e924446b1-69473691.eu-west-2.elb.amazonaws.com 80:30364/TCP 4m37s

NAME READY UP-TO-DATE AVAILABLE AGE

deployment.apps/myspace 4/4 4 4 19s

NAME DESIRED CURRENT READY AGE

replicaset.apps/myspace-7bdfc8c57d 4 4 4 19s

[root@ip-10-0-0-28 ~]# kubectl delete deployment myspace -n dev

deployment.apps "myspace" deleted

[root@ip-10-0-0-28 ~]# kubectl delete svc --all -n dev

service "myservice" deleted

[root@ip-10-0-0-28 ~]# kubectl delete pod --all -n dev

pod "pod-2" deleted

[root@ip-10-0-0-28 ~]# kubectl get all -n dev

No resources found in dev namespace.

namespace to delete

[root@ip-10-0-0-28 ~]# kubectl delete ns dev

namespace "dev" deleted

Switching one tablespace to another space

[root@ip-10-0-0-28 ~]# kubectl config set-context --current --namespace=kube-public

Context "kopsclstr.k8s.local" modified.

[root@ip-10-0-0-28 ~]# kubectl get po

No resources found in kube-public namespace.

[root@ip-10-0-0-28 ~]# kubectl config view

apiVersion: v1

clusters:

- cluster:

certificate-authority-data: DATA+OMITTED

server: https://api-kopsclstr-k8s-local-0kba4s-7dc9e9e90042d909.elb.eu-west-2.amazonaws.com

tls-server-name: api.internal.kopsclstr.k8s.local

contexts:

- context:

cluster: kopsclstr.k8s.local

namespace: kube-public

user: kopsclstr.k8s.local

current-context: kopsclstr.k8s.local

kind: Config

preferences: {}

users:

- name: kopsclstr.k8s.local

user:

client-certificate-data: DATA+OMITTED

client-key-data: DATA+OMITTED

[root@ip-10-0-0-28 ~]# kubectl config set-context --current --namespace=default

Context "kopsclstr.k8s.local" modified.

[root@ip-10-0-0-28 ~]# kubectl get po

NAME READY STATUS RESTARTS AGE

pod-1 1/1 Running 0 52m

[root@ip-10-0-0-28 ~]# kubectl config view

apiVersion: v1

clusters:

- cluster:

certificate-authority-data: DATA+OMITTED

server: https://api-kopsclstr-k8s-local-0kba4s-7dc9e9e90042d909.elb.eu-west-2.amazonaws.com

tls-server-name: api.internal.kopsclstr.k8s.local

contexts:

- context:

cluster: kopsclstr.k8s.local

namespace: default

user: kopsclstr.k8s.local

current-context: kopsclstr.k8s.local

kind: Config

preferences: {}

users:

- name: kopsclstr.k8s.local

user:

client-certificate-data: DATA+OMITTED

client-key-data: DATA+OMITTED

For reference:

--Thanks

Friday, August 15, 2025

Kubernetes part5

Class 89th Kubernetes Part5 August 15th

Step1: Install Kops

[root@ip-10-0-0-22 ~]# curl -Lo kops https://github.com/kubernetes/kops/releases/download/$(curl -s https://api.github.com/repos/kubernetes/kops/releases/latest | grep tag_name | cut -d '"' -f 4)/kops-linux-amd64

Install kubectl

[root@ip-10-0-0-22 ~]# kubectl version
Client Version: v1.33.4
Kustomize Version: v5.6.0
The connection to the server localhost:8080 was refused - did you specify the right host or port?

[root@ip-10-0-0-22 ~]# aws s3 ls

2025-08-16 16:58:08 ccitpublicbucket16

[root@ip-10-0-0-22 ~]# export KOPS_STATE_STORE=s3://ccitpublicbucket16

Step2: Create the cluster

[root@ip-10-0-0-22 ~]# kops create cluster --name kopsclstr.k8s.local --zones eu-west-2b,eu-west-2a --master-count 1 --master-size c7i-flex.large --master-volume-size 20 --node-count 2 --node-size t3.micro --node-volume-size=15 --image=ami-044415bb13eee2391

[root@ip-10-0-0-22 ~]#kops update cluster --name kopsclstr.k8s.local --yes --admin

Step3: Deployment file create for manifest,

[root@ip-10-0-0-22 ~]# cat manifest.yaml

---

apiVersion: apps/v1

kind: Deployment

metadata:

spec:

replicas: 2 # Fixed: lowercase and proper spacing

selector: # Proper selector definition

matchLabels:

app: zamoto

metadata:

labels:

app: zamoto # Must match selector

spec:

containers:

- name: container1

image: shaikmustafa/mygame

ports:

- containerPort: 80

[root@ip-10-0-0-22 ~]# cat service.yaml

---

apiVersion: v1

kind: Service

metadata:

spec:

type: LoadBalancer

selector:

app: zamoto

ports:

- port: 80

targetPort: 80

Step4: So far deployment

pod-->container

rc/rs -->pod-->contrainer

deploy -->rs-->pod -->container

Deployment feature: autoscaling,need to provide these information while deployment,if pod usage 60 % percentage usage pod will create, if usage is less pod will reduced

replication
Scaling(manuall,autoscaling) Autoscalimg:
desired:3
min:2
max10
Rollback to any version
no downtime

Step5: All instance created successfully.

[root@ip-10-0-0-22 ~]# kops validate cluster --wait 10m

[ec2-user@ip-10-0-0-22 ~]$ kubectl get nodes

NAME STATUS ROLES AGE VERSION

i-012484f05449c29f6 Ready control-plane 3m36s v1.32.4

i-0c9c5c020ce9ab366 Ready node 73s v1.32.4

i-0e71b4d0cc69c02c6 Ready node 85s v1.32.4

Step6: Using below command execute manifest file,

[root@ip-10-0-0-22 ~]# kubectl create -f .

deployment.apps/mydeploy created

service/myservice created

Step7: Deployment create , along with replicaset will come

[root@ip-10-0-0-22 ~]# kubectl get deploy

NAME READY UP-TO-DATE AVAILABLE AGE

mydeploy 2/2 2 2 47s

[root@ip-10-0-0-22 ~]# kubectl get rs

NAME DESIRED CURRENT READY AGE

mydeploy-77d4499fd4 2 2 2 104s

Step8: list of Pods

[root@ip-10-0-0-22 ~]# kubectl get pods

NAME READY STATUS RESTARTS AGE

mydeploy-77d4499fd4-7j2xs 1/1 Running 0 2m6s

mydeploy-77d4499fd4-kldnq 1/1 Running 0 2m6s

Step9:list of Services

[root@ip-10-0-0-22 ~]# kubectl get svc

NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE

kubernetes ClusterIP 100.64.0.1 <none> 443/TCP 6m29s

myservice LoadBalancer 100.71.88.229 a8ba63cae87274680944e81acc4a3da6-2050377277.eu-west-2.elb.amazonaws.com 80:30315/TCP 2m56s

Step10: loadbalancer opened

Step11:

[root@ip-10-0-0-22 ~]# kubectl get deploy

NAME READY UP-TO-DATE AVAILABLE AGE

mydeploy 2/2 2 2 11m

[root@ip-10-0-0-22 ~]# kubectl describe deploy

Name: mydeploy

Namespace: default

CreationTimestamp: Sun, 17 Aug 2025 13:31:01 +0000

Labels: <none>

Annotations: deployment.kubernetes.io/revision: 1

Selector: app=zamoto

Replicas: 2 desired | 2 updated | 2 total | 2 available | 0 unavailable

StrategyType: RollingUpdate

MinReadySeconds: 0

RollingUpdateStrategy: 25% max unavailable, 25% max surge

Pod Template:

Labels: app=zamoto

Containers:

container1:

Image: shaikmustafa/mygame

Port: 80/TCP

Host Port: 0/TCP

Environment: <none>

Mounts: <none>

Volumes: <none>

Node-Selectors: <none>

Tolerations: <none>

Conditions:

Type Status Reason

---- ------ ------

Available True MinimumReplicasAvailable

Progressing True NewReplicaSetAvailable

OldReplicaSets: <none>

NewReplicaSet: mydeploy-77d4499fd4 (2/2 replicas created)

Events:

Type Reason Age From Message

---- ------ ---- ---- -------

Normal ScalingReplicaSet 11m deployment-controller Scaled up replica set mydeploy-77d4499fd4 from 0 to 2

Test our features

No down time

Step12: Change the deployment file image changed

[root@ip-10-0-0-22 ~]# vi manifest.yaml

image: shaikmustafa/dm

[root@ip-10-0-0-22 ~]# kubectl apply -f manifest.yaml

Warning: resource deployments/mydeploy is missing the kubectl.kubernetes.io/last-applied-configuration annotation which is required by kubectl apply. kubectl apply should only be used on resources created declaratively by either kubectl create --save-config or kubectl apply. The missing annotation will be patched automatically.

deployment.apps/mydeploy configured

See without downtime ,deployed changed to another webpage

Step13: Though command also we can change image

[root@ip-10-0-0-22 ~]# kubectl set image deploy mydeploy container1=shaikmustafa/cycle

deployment.apps/mydeploy image updated

Step14: Below command rollout can able check ,image deployed or not

[root@ip-10-0-0-22 ~]# kubectl rollout status deploy mydeploy

deployment "mydeploy" successfully rolled out

Step15: shaikmustafa/paytm:movie

[root@ip-10-0-0-22 ~]# kubectl set image deploy mydeploy container1=shaikmustafa/paytm:movie

deployment.apps/mydeploy image updated

[root@ip-10-0-0-22 ~]# kubectl rollout status deploy mydeploy

Waiting for deployment "mydeploy" rollout to finish: 1 out of 2 new replicas have been updated...

Waiting for deployment "mydeploy" rollout to finish: 1 old replicas are pending termination...

deployment "mydeploy" successfully rolled out

[root@ip-10-0-0-22 ~]#

Step16:

Deployment -->RS 1--> 3 pods created First game

After Image updated --RS2 --> 1 pod will create after successfully deployed, remove one pod in Rs1, Same way 2 pod will create after successfully deployed , remove second pod in Rs1

Same way 3 prod will create after successfully deployed ,demote third pod,

all pods deployed into new version application.

This called this strategy in technically "rolling update strategy"

Step17: Planning to rollback the application

After change Replicateset , previous set are not delete it should be presist , you can able to rollback

previous application ,now below one is active one , now the application is paytm movie,

Planning to change Rs3 desire rollback

[root@ip-10-0-0-22 ~]# kubectl get rs

NAME DESIRED CURRENT READY AGE

mydeploy-547d4c47c7 0 0 0 50m

mydeploy-5f87bb8854 0 0 0 36m

mydeploy-77d4499fd4 0 0 0 65m

mydeploy-8565b4b985 2 2 2 30m

Undo command

Here 3 is version

[root@ip-10-0-0-22 ~]# kubectl rollout undo deployment mydeploy --to-revision=3

deployment.apps/mydeploy rolled back

[root@ip-10-0-0-22 ~]# kubectl rollout status deploy mydeploy

deployment "mydeploy" successfully rolled out

Application change to cycle

See here rs active state changed from mydeploy-8565b4b985 to mydeploy-5f87bb8854

[root@ip-10-0-0-22 ~]# kubectl get rs

NAME DESIRED CURRENT READY AGE

mydeploy-547d4c47c7 0 0 0 58m

mydeploy-5f87bb8854 2 2 2 44m

mydeploy-77d4499fd4 0 0 0 73m

mydeploy-8565b4b985 0 0 0 38m

This command will show like 1 pod i creating another pod is terminiated

-w mean watch

[root@ip-10-0-0-22 ~]# kubectl get po -w

NAME READY STATUS RESTARTS AGE

mydeploy-5f87bb8854-b9rp7 0/1 ContainerCreating 0 0s

mydeploy-5f87bb8854-mrbws 1/1 Running 0 3s

mydeploy-8565b4b985-7pv2w 1/1 Terminating 0 57s

mydeploy-8565b4b985-d4lrj 1/1 Running 0 55s

mydeploy-8565b4b985-7pv2w 0/1 Completed 0 58s

mydeploy-8565b4b985-7pv2w 0/1 Completed 0 59s

mydeploy-5f87bb8854-b9rp7 1/1 Running 0 3s

mydeploy-8565b4b985-d4lrj 1/1 Terminating 0 58s

See here i have change version 4

[root@ip-10-0-0-22 ~]# kubectl rollout undo deployment mydeploy --to-revision=4

deployment.apps/mydeploy rolled back

[root@ip-10-0-0-22 ~]# kubectl get po -w

NAME READY STATUS RESTARTS AGE

mydeploy-8565b4b985-7pv2w 1/1 Running 0 11s

mydeploy-8565b4b985-d4lrj 1/1 Running 0 9s

Planning to back to version 2 ,it should not available version 3 will change version 5

[root@ip-10-0-0-22 ~]# kubectl rollout undo deployment mydeploy --to-revision=3

error: unable to find specified revision 3 in history

[root@ip-10-0-0-22 ~]# kubectl rollout undo deployment mydeploy --to-revision=5

deployment.apps/mydeploy rolled back

Now the current application is Cycle

Step18: see here history of deployment version 3 was removed

[root@ip-10-0-0-22 ~]# kubectl rollout history deploy mydeploy

deployment.apps/mydeploy

REVISION CHANGE-CAUSE

1 <none>

2 <none>

6 <none>

7 <none>

[root@ip-10-0-0-22 ~]# kubectl rollout undo deployment mydeploy --to-revision=2

deployment.apps/mydeploy rolled back

[root@ip-10-0-0-22 ~]# kubectl get po -w

NAME READY STATUS RESTARTS AGE

mydeploy-547d4c47c7-4cmnc 1/1 Running 0 4s

mydeploy-547d4c47c7-tfp6p 0/1 ContainerCreating 0 1s

mydeploy-5f87bb8854-b9rp7 1/1 Running 0 9m29s

mydeploy-547d4c47c7-tfp6p 1/1 Running 0 2s

mydeploy-5f87bb8854-b9rp7 1/1 Terminating 0 9m31s

mydeploy-5f87bb8854-b9rp7 0/1 Completed 0 9m32s

mydeploy-5f87bb8854-b9rp7 0/1 Completed 0 9m33s

[root@ip-10-0-0-22 ~]# kubectl rollout history deploy mydeploy

deployment.apps/mydeploy

REVISION CHANGE-CAUSE

1 <none>

6 <none>

7 <none>

8 <none>

Step19: delete the pod , need to check automatically created or not

See after deleted all pod ,created pod 5 sec automatically

[root@ip-10-0-0-22 ~]# kubectl get pods

NAME READY STATUS RESTARTS AGE

mydeploy-547d4c47c7-4cmnc 1/1 Running 0 3m25s

mydeploy-547d4c47c7-tfp6p 1/1 Running 0 3m22s

[root@ip-10-0-0-22 ~]# kubectl delete pod --all

pod "mydeploy-547d4c47c7-4cmnc" deleted

pod "mydeploy-547d4c47c7-tfp6p" deleted

[root@ip-10-0-0-22 ~]# kubectl get pods

NAME READY STATUS RESTARTS AGE

mydeploy-547d4c47c7-b22bc 1/1 Running 0 5s

mydeploy-547d4c47c7-t9x4z 1/1 Running 0 5s

Step20: manually scalein , first increase the pods

[root@ip-10-0-0-22 ~]# cat manifest.yaml

---

apiVersion: apps/v1

kind: Deployment

metadata:

name: mydeploy

spec:

replicas: 4 # Fixed: lowercase and proper spacing

selector: # Proper selector definition

matchLabels:

app: zamoto

template: # Moved to top-level under spec

metadata:

labels:

app: zamoto # Must match selector

spec:

containers:

- name: container1

image: shaikmustafa/dm

ports:

- containerPort: 80

[root@ip-10-0-0-22 ~]# kubectl apply -f manifest.yaml

deployment.apps/mydeploy configured

[root@ip-10-0-0-22 ~]# kubectl get po

NAME READY STATUS RESTARTS AGE

mydeploy-547d4c47c7-b22bc 1/1 Running 0 4m45s

mydeploy-547d4c47c7-sgkc7 1/1 Running 0 9s

mydeploy-547d4c47c7-t9x4z 1/1 Running 0 4m45s

mydeploy-547d4c47c7-zstz8 1/1 Running 0 9s

Scaledown using command:

[root@ip-10-0-0-22 ~]# kubectl scale deploy mydeploy --replicas 2

deployment.apps/mydeploy scaled

[root@ip-10-0-0-22 ~]# kubectl get po

NAME READY STATUS RESTARTS AGE

mydeploy-547d4c47c7-b22bc 1/1 Running 0 5m55s

mydeploy-547d4c47c7-t9x4z 1/1 Running 0 5m55s

Step21: Auto scaling ,Prod metric

metric for the server

https://kubernetes-sigs.github.io/metrics-server/

kubectl apply -f https://github.com/kubernetes-sigs/metrics-server/releases/latest/download/high-availability.yaml

[root@ip-10-0-0-22 ~]# curl -LO https://github.com/kubernetes-sigs/metrics-server/releases/latest/download/high-availability.yaml

% Total % Received % Xferd Average Speed Time Time Time Current

Dload Upload Total Spent Left Speed

0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0

100 4871 100 4871 0 0 16938 0 --:--:-- --:--:-- --:--:-- 16938

[root@ip-10-0-0-22 ~]# sed -i 's|policy/v1beta1|policy/v1|g' high-availability.yaml

[root@ip-10-0-0-22 ~]# kubectl apply -f high-availability.yaml

serviceaccount/metrics-server unchanged

clusterrole.rbac.authorization.k8s.io/system:aggregated-metrics-reader unchanged

clusterrole.rbac.authorization.k8s.io/system:metrics-server unchanged

rolebinding.rbac.authorization.k8s.io/metrics-server-auth-reader unchanged

clusterrolebinding.rbac.authorization.k8s.io/metrics-server:system:auth-delegator unchanged

clusterrolebinding.rbac.authorization.k8s.io/system:metrics-server unchanged

service/metrics-server unchanged

deployment.apps/metrics-server configured

poddisruptionbudget.policy/metrics-server created

apiservice.apiregistration.k8s.io/v1beta1.metrics.k8s.io unchanged

Below command metric-server installed or not using below command

[root@ip-10-0-0-22 ~]# kubectl get deployment metrics-server -n kube-system

NAME READY UP-TO-DATE AVAILABLE AGE

metrics-server 2/2 2 2 5m39s

[root@ip-10-0-0-22 ~]# cat hp.yaml

apiVersion: autoscaling/v2

kind: HorizontalPodAutoscaler

metadata:

spec:

scaleTargetRef:

apiVersion: apps/v1

kind: Deployment

minReplicas: 1

maxReplicas: 5

metrics:

- type: Resource

resource:

target:

type: Utilization

averageUtilization: 50 # Target 50% CPU utilization

Deployment created ,autoscaling will work once 50 % cpu ultization, so you need give command stress to server.

[root@ip-10-0-0-22 ~]# kubectl create -f hp.yaml

horizontalpodautoscaler.autoscaling/nginx-hpa created

Step22: Go to inside the pod

[root@ip-10-0-0-22 ~]# kubectl get po

NAME READY STATUS RESTARTS AGE

mydeploy-547d4c47c7-b22bc 1/1 Running 0 25m

mydeploy-547d4c47c7-t9x4z 1/1 Running 0 25m

[root@ip-10-0-0-22 ~]# kubectl exec -it mydeploy-547d4c47c7-t9x4z -- bash

root@mydeploy-547d4c47c7-t9x4z:/#

Step23:

root@mydeploy-547d4c47c7-t9x4z:/# apt update -y

root@mydeploy-547d4c47c7-t9x4z:/# apt install stress -y

root@mydeploy-547d4c47c7-t9x4z:/# stress -c 2 400 -v

stress: FAIL: [305] (244) unrecognized option: 400

root@mydeploy-547d4c47c7-t9x4z:/# stress -c 2 -t 400 -v

stress: info: [306] dispatching hogs: 2 cpu, 0 io, 0 vm, 0 hdd

stress: dbug: [306] using backoff sleep of 6000us

stress: dbug: [306] setting timeout to 400s

stress: dbug: [306] --> hogcpu worker 2 [307] forked

stress: dbug: [306] using backoff sleep of 3000us

stress: dbug: [306] setting timeout to 400s

stress: dbug: [306] --> hogcpu worker 1 [308] forked

Step24: See below previous 2 pods only, after stress server 5 pods automatically created

See here 5 pods created

Step25: Once you cancel the stress automatically pod will reduced, it will take time

Delete the cluster:

[root@ip-10-0-0-22 ~]# export KOPS_STATE_STORE=s3://ccitpublicbucket16

[root@ip-10-0-0-22 ~]# kops delete cluster --name kopsclstr.k8s.local --yes

Deleted kubectl config for kopsclstr.k8s.local

Deleted cluster: "kopsclstr.k8s.local"

--Thanks