K8s - Hello Minikube

0 - 创建cluster

启动 Minikube 并创建一个集群
minikube start命令将创建并配置一台虚拟机，使其运行单节点 Kubernetes 集群，并且配置 kubectl 安装，以便使其能与 Kubernetes 集群正确通信。

[anliven@anliven ~]$ minikube start
* minikube v1.14.0 on Centos 7.8.2003 (vbox/amd64)
* Using the docker driver based on existing profile
* Starting control plane node minikube in cluster minikube
* Restarting existing docker container for "minikube" ...
* Preparing Kubernetes v1.19.2 on Docker 19.03.8 ...
* Verifying Kubernetes components...
* Enabled addons: default-storageclass, storage-provisioner
* Done! kubectl is now configured to use "minikube" by default
[anliven@anliven ~]$

1 - 创建 Deployment

Kubernetes Pod 是由一个或多个 为了管理和联网而绑定在一起的容器构成的组。
Kubernetes Deployment 检查 Pod 的健康状况，并在 Pod 中的容器终止的情况下重新启动新的容器。
Deployment 是管理 Pod 创建和扩展的推荐方法。

使用名为 echoserver（一个简单的 HTTP 服务器。） 的镜像创建一个 Kubernetes Deployment

[anliven@anliven ~]$ kubectl create deployment hello-node --image=k8s.gcr.io/echoserver:1.4    # 创建管理 Pod 的 Deployment, Pod 根据提供的 Docker 镜像运行 Container
deployment.apps/hello-node created
[anliven@anliven ~]$
[anliven@anliven ~]$ kubectl get deployments    # 查看 Deployment
NAME         READY   UP-TO-DATE   AVAILABLE   AGE
hello-node   1/1     1            1           36s
[anliven@anliven ~]$ 
[anliven@anliven ~]$ kubectl get pods    # 查看 Pod
NAME                          READY   STATUS    RESTARTS   AGE
hello-node-7567d9fdc9-prltr   1/1     Running   0          51s
[anliven@anliven ~]$
[anliven@anliven ~]$ kubectl get events    # 查看集群事件
LAST SEEN   TYPE     REASON                    OBJECT                             MESSAGE
73s         Normal   Scheduled                 pod/hello-node-7567d9fdc9-prltr    Successfully assigned default/hello-node-7567d9fdc9-prltr to minikube
71s         Normal   Pulling                   pod/hello-node-7567d9fdc9-prltr    Pulling image "k8s.gcr.io/echoserver:1.4"
43s         Normal   Pulled                    pod/hello-node-7567d9fdc9-prltr    Successfully pulled image "k8s.gcr.io/echoserver:1.4" in 28.355837001s
43s         Normal   Created                   pod/hello-node-7567d9fdc9-prltr    Created container echoserver
43s         Normal   Started                   pod/hello-node-7567d9fdc9-prltr    Started container echoserver
73s         Normal   SuccessfulCreate          replicaset/hello-node-7567d9fdc9   Created pod: hello-node-7567d9fdc9-prltr
73s         Normal   ScalingReplicaSet         deployment/hello-node              Scaled up replica set hello-node-7567d9fdc9 to 1
35m         Normal   Starting                  node/minikube                      Starting kubelet.
35m         Normal   NodeHasSufficientMemory   node/minikube                      Node minikube status is now: NodeHasSufficientMemory
35m         Normal   NodeHasNoDiskPressure     node/minikube                      Node minikube status is now: NodeHasNoDiskPressure
35m         Normal   NodeHasSufficientPID      node/minikube                      Node minikube status is now: NodeHasSufficientPID
35m         Normal   NodeAllocatableEnforced   node/minikube                      Updated Node Allocatable limit across pods
35m         Normal   Starting                  node/minikube                      Starting kube-proxy.
35m         Normal   RegisteredNode            node/minikube                      Node minikube event: Registered Node minikube in Controller
[anliven@anliven ~]$
[anliven@anliven ~]$ kubectl config view    # 查看 kubectl 配置
apiVersion: v1
clusters:
- cluster:
    certificate-authority: /home/anliven/.minikube/ca.crt
    server: https://192.168.49.2:8443
  name: minikube
contexts:
- context:
    cluster: minikube
    user: minikube
  name: minikube
current-context: minikube
kind: Config
preferences: {}
users:
- name: minikube
  user:
    client-certificate: /home/anliven/.minikube/profiles/minikube/client.crt
    client-key: /home/anliven/.minikube/profiles/minikube/client.key
[anliven@anliven ~]$

2 - 创建 Service

默认情况下，Pod 只能通过 Kubernetes 集群中的内部 IP 地址访问。
要使得容器可以从 Kubernetes 虚拟网络的外部访问，必须将 Pod 暴露为 Kubernetes Service。

[anliven@anliven ~]$ kubectl expose deployment hello-node --type=LoadBalancer --port=8080    # 将 Pod 暴露给公网， --type=LoadBalancer 标志表明将 Service 暴露到集群外部
service/hello-node exposed
[anliven@anliven ~]$
[anliven@anliven ~]$ kubectl get services    # 查看创建的 Service
NAME         TYPE           CLUSTER-IP       EXTERNAL-IP   PORT(S)          AGE
hello-node   LoadBalancer   10.109.212.214   <pending>     8080:32765/TCP   15s
kubernetes   ClusterIP      10.96.0.1        <none>        443/TCP          5h31m
[anliven@anliven ~]$
[anliven@anliven ~]$ minikube service list
|----------------------|---------------------------|--------------|---------------------------|
|      NAMESPACE       |           NAME            | TARGET PORT  |            URL            |
|----------------------|---------------------------|--------------|---------------------------|
| default              | hello-node                |         8080 | http://192.168.49.2:32765 |
| default              | kubernetes                | No node port |
| kube-system          | kube-dns                  | No node port |
| kubernetes-dashboard | dashboard-metrics-scraper | No node port |
| kubernetes-dashboard | kubernetes-dashboard      | No node port |
|----------------------|---------------------------|--------------|---------------------------|
[anliven@anliven ~]$

运行minikube service hello-node命令： 在 Minikube 上，LoadBalancer 使得服务可以通过命令 minikube service 访问。

3 - 启用插件

Minikube 有一组内置的 插件， 可以在本地 Kubernetes 环境中启用、禁用和打开。

[anliven@anliven ~]$ minikube addons list    # 列出当前支持的插件
|-----------------------------|----------|--------------|
|         ADDON NAME          | PROFILE  |    STATUS    |
|-----------------------------|----------|--------------|
| ambassador                  | minikube | disabled     |
| csi-hostpath-driver         | minikube | disabled     |
| dashboard                   | minikube | enabled ✅   |
| default-storageclass        | minikube | enabled ✅   |
| efk                         | minikube | disabled     |
| freshpod                    | minikube | disabled     |
| gcp-auth                    | minikube | disabled     |
| gvisor                      | minikube | disabled     |
| helm-tiller                 | minikube | disabled     |
| ingress                     | minikube | disabled     |
| ingress-dns                 | minikube | disabled     |
| istio                       | minikube | disabled     |
| istio-provisioner           | minikube | disabled     |
| kubevirt                    | minikube | disabled     |
| logviewer                   | minikube | disabled     |
| metallb                     | minikube | disabled     |
| metrics-server              | minikube | disabled     |
| nvidia-driver-installer     | minikube | disabled     |
| nvidia-gpu-device-plugin    | minikube | disabled     |
| olm                         | minikube | disabled     |
| pod-security-policy         | minikube | disabled     |
| registry                    | minikube | disabled     |
| registry-aliases            | minikube | disabled     |
| registry-creds              | minikube | disabled     |
| storage-provisioner         | minikube | enabled ✅   |
| storage-provisioner-gluster | minikube | disabled     |
| volumesnapshots             | minikube | disabled     |
|-----------------------------|----------|--------------|
[anliven@anliven ~]$
[anliven@anliven ~]$ minikube addons enable metrics-server    # 启用插件
* The 'metrics-server' addon is enabled
[anliven@anliven ~]$
[anliven@anliven ~]$ minikube addons list |grep metrics    # 查看状态
| metrics-server              | minikube | enabled ✅   |
[anliven@anliven ~]$
[anliven@anliven ~]$ kubectl get pod,svc -n kube-system    # 查看创建的 Pod 和 Service
NAME                                   READY   STATUS    RESTARTS   AGE
pod/coredns-f9fd979d6-vzcjl            1/1     Running   1          6h1m
pod/etcd-minikube                      1/1     Running   1          6h1m
pod/kube-apiserver-minikube            1/1     Running   1          6h1m
pod/kube-controller-manager-minikube   1/1     Running   1          6h1m
pod/kube-proxy-c7hwx                   1/1     Running   1          6h1m
pod/kube-scheduler-minikube            1/1     Running   1          6h1m
pod/metrics-server-d9b576748-5mh9l     1/1     Running   0          40s    # 刚刚创建的metrics-server
pod/storage-provisioner                1/1     Running   2          6h1m

NAME                     TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)                  AGE
service/kube-dns         ClusterIP   10.96.0.10       <none>        53/UDP,53/TCP,9153/TCP   6h1m
service/metrics-server   ClusterIP   10.103.101.207   <none>        443/TCP                  40s    # 刚刚创建的metrics-server
[anliven@anliven ~]$
[anliven@anliven ~]$ minikube addons disable  metrics-server    # 禁用插件
* "The 'metrics-server' addon is disabled
[anliven@anliven ~]$
[anliven@anliven ~]$ minikube addons list |grep metrics    # 查看状态
| metrics-server              | minikube | disabled     |
[anliven@anliven ~]$
[anliven@anliven ~]$ kubectl get pod,svc -n kube-system
NAME                                   READY   STATUS    RESTARTS   AGE
pod/coredns-f9fd979d6-vzcjl            1/1     Running   1          6h4m
pod/etcd-minikube                      1/1     Running   1          6h4m
pod/kube-apiserver-minikube            1/1     Running   1          6h4m
pod/kube-controller-manager-minikube   1/1     Running   1          6h4m
pod/kube-proxy-c7hwx                   1/1     Running   1          6h4m
pod/kube-scheduler-minikube            1/1     Running   1          6h4m
pod/storage-provisioner                1/1     Running   2          6h4m

NAME               TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)                  AGE
service/kube-dns   ClusterIP   10.96.0.10   <none>        53/UDP,53/TCP,9153/TCP   6h4m
[anliven@anliven ~]$

4 - 清理

清理在集群中创建的资源。

[anliven@anliven ~]$ kubectl get service    # 查看Service
NAME         TYPE           CLUSTER-IP       EXTERNAL-IP   PORT(S)          AGE
hello-node   LoadBalancer   10.109.212.214   <pending>     8080:32765/TCP   50m
kubernetes   ClusterIP      10.96.0.1        <none>        443/TCP          6h21m
[anliven@anliven ~]$
[anliven@anliven ~]$ kubectl get deployment    # 查看deployment
NAME         READY   UP-TO-DATE   AVAILABLE   AGE
hello-node   1/1     1            1           85m
[anliven@anliven ~]$
[anliven@anliven ~]$
[anliven@anliven ~]$ kubectl delete service hello-node    # 清除服务
service "hello-node" deleted
[anliven@anliven ~]$
[anliven@anliven ~]$ kubectl get service
NAME         TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
kubernetes   ClusterIP   10.96.0.1    <none>        443/TCP   6h22m
[anliven@anliven ~]$
[anliven@anliven ~]$ kubectl delete deployment hello-node    # 清除deployment
deployment.apps "hello-node" deleted
[anliven@anliven ~]$
[anliven@anliven ~]$ kubectl get deployment
No resources found in default namespace.
[anliven@anliven ~]$

停止和删除Minikube 集群

[anliven@anliven ~]$ docker ps -a |grep minikube    # 查看Minikube 集群状态
3e7356dd380b        gcr.io/k8s-minikube/kicbase:v0.0.13                                     "/usr/local/bin/entr…"   5 minutes ago       Up 41 seconds              127.0.0.1:32787->22/tcp, 127.0.0.1:32786->2376/tcp, 127.0.0.1:32785->5000/tcp, 127.0.0.1:32784->8443/tcp   minikube
[anliven@anliven ~]$
[anliven@anliven ~]$ minikube stop    # 停止Minikube 集群
* Stopping node "minikube"  ...
* Powering off "minikube" via SSH ...
* 1 nodes stopped.
[anliven@anliven ~]$
[anliven@anliven ~]$ docker ps -a |grep minikube
3e7356dd380b        gcr.io/k8s-minikube/kicbase:v0.0.13                                     "/usr/local/bin/entr…"   7 minutes ago       Exited (130) 4 seconds ago                       minikube
[anliven@anliven ~]$
[anliven@anliven ~]$ minikube status
minikube
type: Control Plane
host: Stopped
kubelet: Stopped
apiserver: Stopped
kubeconfig: Stopped

[anliven@anliven ~]$
[anliven@anliven ~]$ minikube delete    # 删除 Minikube 集群
* Deleting "minikube" in docker ...
* Deleting container "minikube" ...
* Removing /home/anliven/.minikube/machines/minikube ...
* Removed all traces of the "minikube" cluster.
[anliven@anliven ~]$
[anliven@anliven ~]$ docker ps -a |grep minikube
[anliven@anliven ~]$
[anliven@anliven ~]$ docker images |grep k8s    # 查看Minikube 集群的镜像
gcr.io/k8s-minikube/kicbase                                         v0.0.13             90f1294ff9ac        2 weeks ago         800MB
[anliven@anliven ~]$

5 - 参考消息

• https://kubernetes.io/docs/tutorials/hello-minikube/
• https://kubernetes.io/docs/setup/learning-environment/minikube/#quickstart