Kubernetes part2
Class 86th Kubernetes Part1 August 11th
1.Self managed cluster (everything managed by self master server,worker node ,data..etc)
example of using tools
1.minikube (single node cluster) remain all them multi node cluster
2.kops
3.kubeadm
4.k3d
-->2CPUs or more
-->2GB of free memory
-->20 GB of free disk space
-->Internet connection
-->Container or virtual machine manager, such as: Docker
Practical :
Step1: Create one Ec2 instance amazon linux , t3.small 2 VCPU,2 memory 20 GB lunched ,we will try mini 2 gb required.
https://minikube.sigs.k8s.io/docs/start/?arch=%2Fwindows%2Fx86-64%2Fstable%2F.exe+download
Step2:
[ec2-user@ip-10-0-2-53 ~]$ sudo -i [root@ip-10-0-2-53 ~]# 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 % Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0 0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0 100 126M 100 126M 0 0 96.7M 0 0:00:01 0:00:01 --:--:-- 127M rm: remove regular file 'minikube-linux-amd64'? yes [root@ip-10-0-2-53 ~]# minikube version minikube version: v1.36.0 commit: f8f52f5de11fc6ad8244afac475e1d0f96841df1-dirty
Step3: need to install docker
[root@ip-10-0-2-53 ~]# yum install docker -y[root@ip-10-0-2-53 ~]# systemctl start docker● docker.service - Docker Application Container Engine Loaded: loaded (/usr/lib/systemd/system/docker.service; disabled; preset: disabled) Active: active (running) since Wed 2025-08-13 15:20:40 UTC; 19s ago TriggeredBy: ● docker.socketStep4: docker --force with out my permission it will start[root@ip-10-0-2-53 ~]# minikube start --driver=docker --force * minikube v1.36.0 on Amazon 2023.8.20250808 (xen/amd64) ! minikube skips various validations when --force is supplied; this may lead to unexpected behavior * Using the docker driver based on user configuration* kubectl not found. If you need it, try: 'minikube kubectl -- get pods -A' * Done! kubectl is now configured to use "minikube" cluster and "default" namespace bydefault
Step5: minikube status
[root@ip-10-0-2-53 ~]# minikube status
minikube
type: Control Plane
host: Running
kubelet: Running
apiserver: Running
kubeconfig: ConfiguredStep6: git CLI tool git ,docker CLI docker only ,Kubernetes CLI kubectl (add/delete)For Kubernete clusture to communicate, kubectl CLI tool will help Installation kubectl https://kubernetes.io/docs/tasks/tools/install-kubectl-linux/[root@ip-10-0-2-53 ~]# curl -LO "https://dl.k8s.io/release/$(curl -L -s https://dl.k8s.io/release/stable.txt)/bin/linux/amd64/kubectl"
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 138 100 138 0 0 1197 0 --:--:-- --:--:-- --:--:-- 1200
100 57.3M 100 57.3M 0 0 127M 0 --:--:-- --:--:-- --:--:-- 127M
[root@ip-10-0-2-53 ~]#
Step7: We got one kubectl file ,for give execute permission to the file
[root@ip-10-0-2-53 ~]# ls -lrt
total 58724
-rw-r--r--. 1 root root 60129464 Aug 13 19:34 kubectl
[root@ip-10-0-2-53 ~]# chmod -x kubectl
[root@ip-10-0-2-53 ~]# mv kubectl /usr/local/bin/
[root@ip-10-0-2-53 ~]# sudo chmod 777 /usr/local/bin/kubectl
[root@ip-10-0-2-53 ~]# kubectl version
Client Version: v1.33.3
Kustomize Version: v5.6.0
Server Version: v1.33.1
Pod (inside container, inside container application),pod is smallest portion
Note:
Kubernetes will not deploy the containers directly on worker nodes.
Kubernetes has a object called POD which contains containers . Lets learn about PODS
if you want see all the resource in Kubernetes give this command , these are Kubernetes object
smallest object is in Kubernetes pod , one pod has one container or multiple container
We always work with pods only
[root@ip-10-0-2-53 ~]# kubectl api-resources
Step1: list of pods to see the command
[root@ip-10-0-2-53 ~]# kubectl get pods
No resources found in default namespace.
or
[root@ip-10-0-2-53 ~]# kubectl get po
No resources found in default namespace.
if required you can put aliase in bash_profile
Imperative Way :
Create the pod in imperative way ,below one 1 pod has 1 container is running
[root@ip-10-0-2-53 ~]# kubectl run pod-1 --image=nginx
pod/pod-1 created
[root@ip-10-0-2-53 ~]# kubectl get po
NAME READY STATUS RESTARTS AGE
pod-1 1/1 Running 0 17s
Step2: to get the pod ip ,we can know how many pod and node cluster ,here we used single node cluster
[root@ip-10-0-2-53 ~]# kubectl get po -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
pod-1 1/1 Running 0 119s 10.244.0.3 minikube <none> If you want see yaml format [root@ip-10-0-2-53 ~]# kubectl get po -o yamlIf you want see json format [root@ip-10-0-2-53 ~]# kubectl get po -o jsonStep3: Creating some more pods [root@ip-10-0-2-53 ~]# kubectl run mypod --image=httpd
pod/mypod created
[root@ip-10-0-2-53 ~]# kubectl get po -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
mypod 1/1 Running 0 10s 10.244.0.4 minikube <none> <none>
pod-1 1/1 Running 0 7m39s 10.244.0.3 minikube <none> <none>
Declarative Way : manifest fileWrite file for pod creation apiVersion , V should be capital letter , here multiple thingmultiple version there (deployment,pod,rba), we can that using the kubectl api-resources commandStep1: Metadata is information about data ,mycontainer container name ,nginx port 80[root@ip-10-0-2-53 ~]# vi manifest.yaml [root@ip-10-0-2-53 ~]# cat manifest.yaml --- apiVersion: v1 kind: Pod metadata: name: newpod1 spec: containers: - name: mycontainer image: nginx ports: - containerPort: 80 [root@ip-10-0-2-53 ~]# kubectl create -f manifest.yaml pod/newpod1 createdStep4: new pod created
[root@ip-10-0-2-53 ~]# kubectl get po -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
mypod 1/1 Running 0 19m 10.244.0.4 minikube <none> <none>
newpod1 1/1 Running 0 64s 10.244.0.5 minikube <none> <none>
pod-1 1/1 Running 0 27m 10.244.0.3 minikube <none> <none>
Step5: if you want details of the pod give below command , you will get complete information about the detail ,if any pod not working ,we have to check first this command only.
[root@ip-10-0-2-53 ~]# kubectl describe pod newpod1
Name: newpod1
Namespace: default
Priority: 0
Service Account: default
Node: minikube/192.168.49.2
Start Time: Wed, 13 Aug 2025 20:23:23 +0000
Labels: <none>
Annotations: <none>
Status: Running
IP: 10.244.0.5
IPs:
IP: 10.244.0.5
Containers:
mycontainer:
Container ID: docker://299b8337f2320bcfa6abc75abf077fda16e1c192b26c2db69a43c6071375456a
Image: nginx
Image ID: docker-pullable://nginx@sha256:3ab4ed065a1437cbbd45e65617b1285bdf6523c6bf56a121e00df41720e09a89
Port: 80/TCP
Host Port: 0/TCP
State: Running
Started: Wed, 13 Aug 2025 20:23:25 +0000
Ready: True
Restart Count: 0
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-pgtgr (ro)
Conditions:
Type Status
PodReadyToStartContainers True
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
kube-api-access-pgtgr:
Type: Projected (a volume that contains injected data from multiple sources)
TokenExpirationSeconds: 3607
ConfigMapName: kube-root-ca.crt
Optional: false
DownwardAPI: true
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 3m default-scheduler Successfully assigned default/newpod1 to minikube
Normal Pulling 2m59s kubelet Pulling image "nginx"
Normal Pulled 2m58s kubelet Successfully pulled image "nginx" in 1.036s (1.036s including waiting). Image size: 192237226 bytes.
Normal Created 2m58s kubelet Created container: mycontainer
Normal Started 2m58s kubelet Started container mycontainer
See above all event we can see
Step6: delete the pod using below command
[root@ip-10-0-2-53 ~]# kubectl delete pod mypod
pod "mypod" deleted
[root@ip-10-0-2-53 ~]# kubectl get po
NAME READY STATUS RESTARTS AGE
newpod1 1/1 Running 0 7m57s
pod-1 1/1 Running 0 33m
To delete all pods
[root@ip-10-0-2-53 ~]# kubectl delete pod --all
pod "newpod1" deleted
pod "pod-1" deleted
[root@ip-10-0-2-53 ~]# kubectl get po
No resources found in default namespace.
Label :
Step1:
Pod Labelling
Whenever we create the pod ,we should expose the pod so the application in the pod container able access internet or out side
For expose the pod ,we use services
[root@ip-10-0-2-53 ~]# vi manifest.yaml
[root@ip-10-0-2-53 ~]# cat manifest.yaml
---
apiVersion: v1
kind: Pod
metadata:
name: newpod1
labels:
app: swiggy
spec:
containers:
- name: container-1
image: nginx
ports:
- containerPort: 80
[root@ip-10-0-2-53 ~]# kubectl create -f manifest.yaml
pod/newpod1 created
Pod created succesfully
[root@ip-10-0-2-53 ~]# kubectl get po
NAME READY STATUS RESTARTS AGE
newpod1 1/1 Running 0 30s
Step2: We can create one po and container
[root@ip-10-0-2-53 ~]# vi manifest.yaml
[root@ip-10-0-2-53 ~]# cat manifest.yaml
---
apiVersion: v1
kind: Pod
metadata:
name: newpod2
labels:
app: uber
spec:
containers:
- name: container-1
image: nginx
ports:
- containerPort: 80
[root@ip-10-0-2-53 ~]# kubectl create -f manifest.yaml
pod/newpod2 created
[root@ip-10-0-2-53 ~]# vi manifest.yaml
[root@ip-10-0-2-53 ~]# cat manifest.yaml
---
apiVersion: v1
kind: Pod
metadata:
name: newpod3
labels:
app: zomato
spec:
containers:
- name: container-1
image: nginx
ports:
- containerPort: 80
[root@ip-10-0-2-53 ~]# kubectl create -f manifest.yaml
pod/newpod3 created
[root@ip-10-0-2-53 ~]# cat manifest.yaml
---
apiVersion: v1
kind: Pod
metadata:
name: newpod4
labels:
app: uber
spec:
containers:
- name: container-1
image: nginx
ports:
- containerPort: 80
[root@ip-10-0-2-53 ~]# kubectl create -f manifest.yaml
pod/newpod4 created
[root@ip-10-0-2-53 ~]# kubectl get po --show-labels
NAME READY STATUS RESTARTS AGE LABELS
newpod1 1/1 Running 0 8m7s app=swiggy
newpod2 1/1 Running 0 5m app=uber
newpod3 1/1 Running 0 3m21s app=zomato
newpod4 1/1 Running 0 95s app=uber
Step3: if you want get only uber label pods using below command
[root@ip-10-0-2-53 ~]# kubectl get po -l app=uber
NAME READY STATUS RESTARTS AGE
newpod2 1/1 Running 0 6m28s
newpod4 1/1 Running 0 3m3s
[root@ip-10-0-2-53 ~]# kubectl get po -l app=zomato
NAME READY STATUS RESTARTS AGE
newpod3 1/1 Running 0 4m59s
Single base select is called equality based selector
Step4: multiple label to select
[root@ip-10-0-2-53 ~]# kubectl get po -l 'app in(zomato,uber)'
NAME READY STATUS RESTARTS AGE
newpod2 1/1 Running 0 10m
newpod3 1/1 Running 0 9m17s
newpod4 1/1 Running 0 7m31s
We can called set based sector
Step5: i have create one po newpod5 lable not exist ,we can attache the label
[root@ip-10-0-2-53 ~]# kubectl run newpod5 --image=nginx
pod/newpod5 created
[root@ip-10-0-2-53 ~]# kubectl get po --show-labels
NAME READY STATUS RESTARTS AGE LABELS
newpod1 1/1 Running 0 17m app=swiggy
newpod2 1/1 Running 0 14m app=uber
newpod3 1/1 Running 0 12m app=zomato
newpod4 1/1 Running 0 10m app=uber
newpod5 1/1 Running 0 7s run=newpod5
Step6:
[root@ip-10-0-2-53 ~]# kubectl label pod newpod5 app=swiggy
pod/newpod5 labeled
[root@ip-10-0-2-53 ~]# kubectl get po --show-labels
NAME READY STATUS RESTARTS AGE LABELS
newpod1 1/1 Running 0 19m app=swiggy
newpod2 1/1 Running 0 16m app=uber
newpod3 1/1 Running 0 14m app=zomato
newpod4 1/1 Running 0 13m app=uber
newpod5 1/1 Running 0 2m21s app=swiggy,run=newpod5
[root@ip-10-0-2-53 ~]# kubectl label pod newpod2 env=dev
pod/newpod2 labeled
[root@ip-10-0-2-53 ~]# kubectl get po --show-labels
NAME READY STATUS RESTARTS AGE LABELS
newpod1 1/1 Running 0 21m app=swiggy
newpod2 1/1 Running 0 18m app=uber,env=dev
newpod3 1/1 Running 0 16m app=zomato
newpod4 1/1 Running 0 14m app=uber
newpod5 1/1 Running 0 3m51s app=swiggy,run=newpod5
[root@ip-10-0-2-53 ~]# kubectl get po -l app=swiggy
NAME READY STATUS RESTARTS AGE
newpod1 1/1 Running 0 22m
newpod5 1/1 Running 0 5m10s
[root@ip-10-0-2-53 ~]# kubectl get po -l app!=swiggy
NAME READY STATUS RESTARTS AGE
newpod2 1/1 Running 0 19m
newpod3 1/1 Running 0 17m
newpod4 1/1 Running 0 16m
Node selector -->we need inform prior, which worker node pod going to be created
Worker node we have make it label , and master node will decided based on label create the pod
Reference Document:
https://mustafa-k8s.hashnode.dev/essential-kubernetes-pod-concepts-for-beginners-to-master
https://mustafa-k8s.hashnode.dev/labels-selectors-and-node-selectors
--Thanks
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