Kubernetes has become the standard for container orchestration, enabling developers and DevOps teams to manage containerized applications efficiently and securely. It has a vibrant ecosystem and a vast community that continues to drive innovation and adoption of cloud-native technologies.

In kubernetes series article, we will explore Kubernetes’ essential features, its role in managing containerized workloads, and its extensibility options, empowering developers to harness its full potential.

Before we introduction the environment preparation and cluster. Here will introduction the key concepts in kubernetes:

  • Pods: The smallest deployable units in Kubernetes, representing one or more containers.
  • Services: An abstraction that provides stable network endpoints to access a set of pods.
  • ReplicaSets: Ensures a specified number of identical pods are running at all times.
  • Deployments: A higher-level abstraction for managing rolling updates and rollbacks of application replicas.
  • Namespaces: A virtual cluster within a physical cluster that allows resource segregation and isolation.

Interact with EKS cluster

Setting your work instanances interact with EKS cluster:

aws eks update-kubeconfig --region $AWS_REGION --name $EKS_CLUSTER_NAME

checkout the config

cat ~/.kube/config

Test

kubectl get svc

Create namespaces

create namespaces for kubernetes arrange the resources.

$ kubectl create namespace eks-sample-app

namespace/eks-sample-app created

Deploy Application

Deploy an eks-sample-app to EKS cluster

Save fellowing to eks-sample-deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: eks-sample-linux-deployment
  namespace: eks-sample-app
  labels:
    app: eks-sample-linux-app
# setting the replicaset rule
spec:
  replicas: 3
  selector:
    matchLabels:
      app: eks-sample-linux-app
  # pod template
  template:
    metadata:
      labels:
        app: eks-sample-linux-app
    spec:
      affinity:
        nodeAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            nodeSelectorTerms:
            - matchExpressions:
              - key: kubernetes.io/arch
                operator: In
                values:
                - amd64
                - arm64
      containers:
      - name: nginx
        image: public.ecr.aws/nginx/nginx:1.23
        ports:
        - name: http
          containerPort: 80
        imagePullPolicy: IfNotPresent
      nodeSelector:
        kubernetes.io/os: linux

Deploy application

kubectl apply -f eks-sample-deployment.yaml

Create service

Create service naming, and other services can interaction by naming (also IP).

Here we create a service yaml, and in spec.type as LoadBalancer

(The Service “eks-sample-linux-service” is invalid: spec.type: Unsupported value: “LoadBalanceer”: supported values: “ClusterIP”, “ExternalName”, “LoadBalancer”, “NodePort”)

eks-sample-service.yaml

apiVersion: v1
kind: Service
metadata:
  name: eks-sample-linux-service
  namespace: eks-sample-app
  labels:
    app: eks-sample-linux-app
spec:
  type: LoadBalancer
  selector:
    app: eks-sample-linux-app
  ports:
    - protocol: TCP
      port: 80
      targetPort: 80

Apply service to cluster

kubectl apply -f eks-sample-service.yaml

If you have change the cluster.yaml, can execute the upgrade command

eksctl upgrade cluster -f cluster.yaml

Preview your Resources in Cluster

List all resource in cluster by namespace

kubectl get all -n eks-sample-app

When list cluster resource, will list the service info, we can access the service by EXTERNAL-IP

curl {EXTERNAL-IP}