k8s快速入门

1.快速创建k8s集群

点击教程菜单 1. Create a Cluster -> Interactive Tutorial - Creating a Cluster

note：通过 Kubernetes 的命令行工具 kubectl 远程管理集群

minikube start 创建集群

kubectl cluster-info 查看集群信息

Kubernetes master is running at https://172.17.0.15:8443

KubeDNS is running at https://172.17.0.15:8443/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy

kubectl get nodes 查看节点信息

NAME STATUS ROLES AGE VERSION

minikube Ready master 2m53s v1.13.3

2.部署应用

kubectl run kubernetes-bootcamp --image=docker.io/jocatalin/kubernetes-bootcamp:v1 --port=8080

显示信息

kubectl run --generator=deployment/apps.v1 is DEPRECATED and will be removed in a future version. Use kubectl run --generator=run-pod/v1 or kubectl create instead.

deployment.apps/kubernetes-bootcamp created

这里我们通过 kubectl run 部署了一个应用，命名为 kubernetes-bootcamp --image 指定Docker 镜像 --port 设置应用对外服务的端口

3.访问应用

默认情况下，所有 Pod只能在集群内部访问。为了能够从外部访问应用，我们需要将容器的 8080 端口映射到节点的端口。

kubectl expose deployment/kubernetes-bootcamp --type="NodePort" --port 8080

显示信息

service/kubernetes-bootcamp exposed

查看services及对应的映射端口

kubectl get services

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

kubernetes ClusterIP 10.96.0.1 443/TCP 9m47s

kubernetes-bootcamp NodePort 10.105.140.245 8080:31048/TCP 82s

kubernetes 是默认的 service，暂时不用考虑。kubernetes-bootcamp 是我们应用的 service，8080 端口已经映射到 host01 的 31048 端口，端口号是随机分配的

通过curl命令进行访问

curl host01:30393

Hello Kubernetes bootcamp! | Running on: kubernetes-bootcamp-6c5cfd894b-ccqz7 | v=1

4.Scale 应用

默认情况下应用只会运行一个副本，可以通过 kubectl get deployments查看副本数。

kubectl get deployments

NAME READY UP-TO-DATE AVAILABLE AGE

kubernetes-bootcamp 1/1 1 1 2m

增加副本个数

kubectl scale deployments/kubernetes-bootcamp --replicas=3

deployment.extensions/kubernetes-bootcamp scaled

$ kubectl get deployments

NAME READY UP-TO-DATE AVAILABLE AGE

kubernetes-bootcamp 3/3 3 3 2m34s

减少副本个数

$ kubectl scale deployments/kubernetes-bootcamp --replicas=1

deployment.extensions/kubernetes-bootcamp scaled

$ kubectl get deployments

NAME READY UP-TO-DATE AVAILABLE AGE

kubernetes-bootcamp 1/1 1 1 3m51s

$ kubectl get pods

NAME READY STATUS RESTARTS AGE

kubernetes-bootcamp-6c5cfd894b-9cn54 1/1 Running 0 41s

kubernetes-bootcamp-6c5cfd894b-ccqz7 1/1 Running 0 4m44s

kubernetes-bootcamp-6c5cfd894b-gnhgz 1/1 Running 0 41s

$ kubectl scale deployments/kubernetes-bootcamp --replicas=1

deployment.extensions/kubernetes-bootcamp scaled

$ kubectl get pods

NAME READY STATUS RESTARTS AGE

kubernetes-bootcamp-6c5cfd894b-9cn54 1/1 Terminating 0 57s

kubernetes-bootcamp-6c5cfd894b-ccqz7 1/1 Running 0 5m

kubernetes-bootcamp-6c5cfd894b-gnhgz 1/1 Terminating 0 57s

4.滚动更新

当前应用使用的 image 版本为 v1，执行如下命令将其升级到 v2：

$ kubectl set image deployments/kubernetes-bootcamp kubernetes-bootcamp=jocatalin/kubernetes-bootcamp:v2

deployment.extensions/kubernetes-bootcamp image updated

$ kubectl get pods

NAME READY STATUS RESTARTS AGE

kubernetes-bootcamp-5bf4d5689b-4k5lb 1/1 Running 0 3s

kubernetes-bootcamp-5bf4d5689b-b9szr 1/1 Running 0 4s

kubernetes-bootcamp-5bf4d5689b-sxxs5 1/1 Running 0 4s

kubernetes-bootcamp-5bf4d5689b-zftkx 1/1 Running 0 3s

kubernetes-bootcamp-6c5cfd894b-ccqz7 1/1 Terminating 0 6m25s

kubernetes-bootcamp-6c5cfd894b-r4mtd 1/1 Terminating 0 6s

kubernetes-bootcamp-6c5cfd894b-r6txw 1/1 Terminating 0 6s

kubernetes-bootcamp-6c5cfd894b-vnbd6 1/1 Terminating 0 6s

$ curl host01:30393

Hello Kubernetes bootcamp! | Running on: kubernetes-bootcamp-5bf4d5689b-zftkx | v=2

通过 kubectl get pods 可以观察滚动更新的过程：v1 的 Pod 被逐个删除，同时启动了新的 v2 Pod。更新完成后访问新版本应用。

如果要回退到 v1 版本也很容易，执行 kubectl rollout undo 命令：

$ kubectl rollout undo deployments/kubernetes-bootcamp

deployment.extensions/kubernetes-bootcamp rolled back

$ curl host01:30393

Hello Kubernetes bootcamp! | Running on: kubernetes-bootcamp-6c5cfd894b-pq7kv | v=1

原文出处：https://www.cnblogs.com/i-dandan/p/10907997.html