4-Kubernetes基础实战操作与配置

[TOC]

基础示例

####

2.使用port-forward访问集群中的应用程序

描述:在实际进行Debug时使用 kubectl port-forward 访问 Kubernetes 集群中的 Redis Server进行调试;

Step1.分别为Redis创建Deployment和Service Deployment

cat > redis-master-deployment.yaml<<'END'
apiVersion: apps/v1
kind: Deployment
metadata:
  name: redis-master-deployment
  labels:
    app: redis
spec:
  selector:
    matchLabels:
      app: redis
      role: master
      tier: backend
  replicas: 1
  template:
    metadata:
      labels:
        app: redis
        role: master
        tier: backend
    spec:
      containers:
      - name: master
        image: redis
        resources:
          requests:
            cpu: 100m
            memory: 100Mi
        ports:
        - containerPort: 6379
END

Service

cat > redis-master-service.yaml<<'END'
apiVersion: v1
kind: Service
metadata:
  name: redis-master-service
  labels:
    app: redis
    role: master
    tier: backend
spec:
  ports:
  - port: 6379
    targetPort: 6379
  selector:
    app: redis
    role: master
    tier: backend
END

Step2.执行apply命令以创建 Redis Deployment与Service:

kubectl apply -f redis-master-deployment.yaml
# deployment.apps/redis-master-deployment created

kubectl apply -f redis-master-service.yaml
# service/redis-master-service created

Step3.分别查看deployment与service部署情况:

kubectl get pods
# NAME                                       READY   STATUS    RESTARTS   AGE
# redis-master-deployment-7d557b94bb-bzw2v   1/1     Running   0          3m2s

#查看 Deployment状态
kubectl get deployment
# NAME                      READY   UP-TO-DATE   AVAILABLE   AGE
# redis-master-deployment   1/1     1            1           3m49s

# 查看 ReplicaSet(副本) 状态
kubectl get rs
# NAME                                 DESIRED   CURRENT   READY   AGE
# redis-master-deployment-7d557b94bb   1         1         1       4m46s

# 检查 Service 创建结果
kubectl get svc -o wide | grep redis
# redis-master-service   ClusterIP   10.99.192.159   <none>        6379/TCP   9m27s   app=redis,role=master,tier=backend

# 验证 Redis Service已经运行并监听了 6379 端口
kubectl get pods redis-master-deployment-7d557b94bb-bzw2v --template='{{(index (index .spec.containers 0).ports 0).containerPort}}{{"n"}}'
# 6379

Step4.使用kubectl port-forward 命令转发本地端口到Pod的端口,用户可以使用资源的名称来进行端口转发

#(1)下面的命令中的任意一行，都可以实现端口转发的效果：
kubectl port-forward redis-master-deployment-7d557b94bb-bzw2v 7000:6379
kubectl port-forward pods/redis-master-deployment-7d557b94bb-bzw2v 7000:6379 # kubectl get pods 获取资源名称
kubectl port-forward deployment/redis-master-deployment 7000:6379 # kubectl get deployments 获取资源名称
kubectl port-forward svc/redis-master-service 7000:6379 # kubectl get svc 获取资源名称
kubectl port-forward rs/redis-master-deployment-7d557b94bb 7000:6379 # kubectl get rs 获取资源名称

#(2)以上命令的输出结果类似：
[[email protected] ~]$ kubectl port-forward --address 127.0.0.1,10.10.107.191  redis-master-deployment-7d557b94bb-bzw2v 7000:6379
# Forwarding from 127.0.0.1:7000 -> 6379
# Handling connection for 7000 (连接到此端口反应)
redis-cli -h 10.10.107.191 -p 7000
# 10.10.107.191:7000> ping
# PONG

Step5.总结本机 7000 端口的连接被转发到集群中 Redis Server 所在 Pod 的 6379 端口。利用该命令可以方便开发或者运维人员进行Debug调试;

注意事项:

1) 由于已知的限制，目前的端口转发仅适用于 TCP 协议。在 issue 47862 中正在跟踪对 UDP 协议的支持。

cat <<EOF | kubectl apply -f -
apiVersion: v1
kind: Pod
metadata:
 name: alpine-app
spec:
 containers:
name: alpine-app
image: alpine
args:
 
sleep
“100000”
EOF
pod/alpine-app created
 k get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
alpine-app 1/1 Running 0 116s 10.100.37.194 worker-02