Deploying Applications as Containers with Kubernetes

# Tải và cài đặt minikube binary

$ 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

# Khởi động cluster

$ minikube start

* minikube v1.35.0 on Fedora 42

* Automatically selected the kvm2 driver

* Creating kvm2 VM (CPUs=2, Memory=2200MB, Disk=20000MB) ...

* Preparing Kubernetes v1.31.0 on Docker 27.2.0 ...

* Done! kubectl is now configured to use "minikube"

# Kiểm tra cluster

$ minikube version

minikube version: v1.35.0

$ kubectl cluster-info

Kubernetes control plane is running at https://localhost:36355

CoreDNS is running at https://localhost:36355/api/v1/namespaces/kube-system/...

# Xem thông tin nodes

$ kubectl get nodes

NAME STATUS ROLES AGE VERSION

minikube Ready control-plane 5m v1.31.0

# Xem tất cả pods ở mọi namespace

$ kubectl get pods --all-namespaces

NAMESPACE NAME READY STATUS RESTARTS

kube-system coredns-7db6d8ff4d-x9p5t 1/1 Running 0

kube-system etcd-minikube 1/1 Running 0

kube-system kube-apiserver-minikube 1/1 Running 0

# Deploy nginx nhanh

$ kubectl create deployment nginx-demo --image=nginx:latest

deployment.apps/nginx-demo created

$ kubectl get pods

NAME READY STATUS RESTARTS AGE

nginx-demo-7d458d8d74-xk9p2 1/1 Running 0 30s

# Describe pod chi tiết

$ kubectl describe pod nginx-demo-7d458d8d74-xk9p2

Name: nginx-demo-7d458d8d74-xk9p2

Namespace: default

Node: minikube/192.168.49.2

Status: Running

IP: 10.244.0.5

# Xem logs của pod

$ kubectl logs nginx-demo-7d458d8d74-xk9p2

/docker-entrypoint.sh: /docker-entrypoint.d/ is not empty, will attempt to perform configuration

# Exec vào container

$ kubectl exec -it nginx-demo-7d458d8d74-xk9p2 -- bash

root@nginx-demo-7d458d8d74-xk9p2:/# nginx -v

nginx version: nginx/1.27.3

---

apiVersion

kind

metadata

name: nginx-deployment

namespace: default

labels:

app: nginx

spec

replicas: 3

selector:

matchLabels:

app: nginx

template:

metadata:

labels:

app: nginx

spec:

containers:

- name: nginx

image: nginx:1.27

ports:

- containerPort: 80

resources:

requests:

memory: "64Mi"

cpu: "250m"

limits:

memory: "128Mi"

cpu: "500m"

---

apiVersion

kind

metadata

name: nginx-service

spec

type: NodePort

selector:

app: nginx

ports:

- port: 80

targetPort: 80

nodePort: 30080

$ kubectl apply -f nginx-deployment.yaml

deployment.apps/nginx-deployment created

service/nginx-service created

$ kubectl get pods -l app=nginx

NAME READY STATUS RESTARTS AGE

nginx-deployment-5d9d547f98-4j2kp 1/1 Running 0 45s

nginx-deployment-5d9d547f98-7m9xz 1/1 Running 0 45s

nginx-deployment-5d9d547f98-r8qlt 1/1 Running 0 45s

$ kubectl get services

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

kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 30m

nginx-service NodePort 10.103.42.181 <none> 80:30080/TCP 45s

$ minikube service nginx-service --url

http://192.168.49.2:30080

# Scale deployment lên 5 replicas

$ kubectl scale deployment nginx-deployment --replicas=5

deployment.apps/nginx-deployment scaled

$ kubectl get pods -l app=nginx

NAME READY STATUS RESTARTS AGE

nginx-deployment-5d9d547f98-4j2kp 1/1 Running 0 5m

nginx-deployment-5d9d547f98-7m9xz 1/1 Running 0 5m

nginx-deployment-5d9d547f98-r8qlt 1/1 Running 0 5m

nginx-deployment-5d9d547f98-wk2pl 1/1 Running 0 15s

nginx-deployment-5d9d547f98-zt8mn 1/1 Running 0 15s

# Rolling update - thay đổi image version

$ kubectl set image deployment/nginx-deployment nginx=nginx:1.28

deployment.apps/nginx-deployment image updated

$ kubectl rollout status deployment/nginx-deployment

Waiting for deployment "nginx-deployment" rollout to finish: 2 out of 5 new replicas have been updated...

Waiting for deployment "nginx-deployment" rollout to finish: 3 out of 5 new replicas have been updated...

deployment "nginx-deployment" successfully rolled out

# Rollback nếu có vấn đề

$ kubectl rollout undo deployment/nginx-deployment

deployment.apps/nginx-deployment rolled back

$ kubectl rollout history deployment/nginx-deployment

deployment.apps/nginx-deployment

REVISION CHANGE-CAUSE

1 <none>

2 <none>

apiVersion

kind

metadata

name: app-config

namespace: production

data

APP_ENV: "production"

APP_PORT: "8080"

DATABASE_HOST: "db.production.svc.cluster.local"

nginx.conf: |

server {

listen 80;

root /var/www/html;

}

# Tạo namespace

$ kubectl create namespace production

namespace/production created

$ kubectl get namespaces

NAME STATUS AGE

default Active 30m

kube-system Active 30m

production Active 5s

# Apply ConfigMap

$ kubectl apply -f app-configmap.yaml

$ kubectl get configmap -n production

NAME DATA AGE

app-config 4 10s

$ kubectl describe configmap app-config -n production

# Cài đặt Helm

$ curl https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3 | bash

Downloading https://get.helm.sh/helm-v3.16.2-linux-amd64.tar.gz

helm installed into /usr/local/bin/helm

# Thêm Bitnami repo

$ helm repo add bitnami https://charts.bitnami.com/bitnami

$ helm repo update

# Cài WordPress qua Helm

$ helm install my-wordpress bitnami/wordpress \

--set wordpressUsername=admin \

--set wordpressPassword=securepass \

--namespace wordpress \

--create-namespace

NAME: my-wordpress

STATUS: deployed

# Liệt kê releases

$ helm list --all-namespaces

NAME NAMESPACE REVISION STATUS CHART

my-wordpress wordpress 1 deployed wordpress-23.0.1

# Upgrade và uninstall

$ helm upgrade my-wordpress bitnami/wordpress --set replicaCount=2

$ helm uninstall my-wordpress -n wordpress