kubernetes实战练习1（2）-阿里云开发者社区

kubernetes实战练习1（2）

2022-12-13 194

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简介： kubernetes实战练习1（2）

3. 使用 Kubectl 启动容器

在此场景中，您将学习如何使用 Kubectl 创建和启动部署、复制控制器并通过服务公开它们，而无需编写yaml定义。

3.1 启动集群

$ minikube start --wait=false
* minikube v1.8.1 on Ubuntu 18.04
* Using the none driver based on user configuration
* Running on localhost (CPUs=2, Memory=2460MB, Disk=145651MB) ...
* OS release is Ubuntu 18.04.4 LTS
* Preparing Kubernetes v1.17.3 on Docker 19.03.6 ...
  - kubelet.resolv-conf=/run/systemd/resolve/resolv.conf
* Launching Kubernetes ... 
* Enabling addons: default-storageclass, storage-provisioner
* Configuring local host environment ...
* Done! kubectl is now configured to use "minikube"
$ kubectl get nodes
NAME       STATUS   ROLES    AGE     VERSION
minikube   Ready    master   2m13s   v1.17.3

3.2 Kubectl 运行

启动一个基于 Docker 镜像katacoda/docker-http-server:latest的容器

$ kubectl run http --image=katacoda/docker-http-server:latest --replicas=1
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/http created
$ kubectl get deployments
NAME   READY   UP-TO-DATE   AVAILABLE   AGE
http   1/1     1            1           25s
$ kubectl describe deployment http
Name:                   http
Namespace:              default
CreationTimestamp:      Sun, 07 Nov 2021 04:53:59 +0000
Labels:                 run=http
Annotations:            deployment.kubernetes.io/revision: 1
Selector:               run=http
Replicas:               1 desired | 1 updated | 1 total | 1 available | 0 unavailable
StrategyType:           RollingUpdate
MinReadySeconds:        0
RollingUpdateStrategy:  25% max unavailable, 25% max surge
Pod Template:
  Labels:  run=http
  Containers:
   http:
    Image:        katacoda/docker-http-server:latest
    Port:         <none>
    Host Port:    <none>
    Environment:  <none>
    Mounts:       <none>
  Volumes:        <none>
Conditions:
  Type           Status  Reason
  ----           ------  ------
  Available      True    MinimumReplicasAvailable
  Progressing    True    NewReplicaSetAvailable
OldReplicaSets:  <none>
NewReplicaSet:   http-774bb756bb (1/1 replicas created)
Events:
  Type    Reason             Age   From                   Message
  ----    ------             ----  ----                   -------
  Normal  ScalingReplicaSet  31s   deployment-controller  Scaled up replica set http-774bb756bb to 1

3.3 Kubectl 暴露

创建部署后，我们可以使用kubectl创建一个服务，该服务在特定端口上公开Pod。

通过kubectl 暴露新部署的http部署。该命令允许您定义服务的不同参数以及如何公开部署。

使用下面的命令暴露主机8000上的容器端口80绑定到主机的external-ip。

$ kubectl expose deployment http --external-ip="172.17.0.34" --port=8000 --target-port=80
service/http exposed
$ curl http://172.17.0.34:8000
<h1>This request was processed by host: http-774bb756bb-thlz6</h1>

3.4 Kubectl 运行和公开

使用kubectl run可以创建部署并将其公开为单个命令。

$ kubectl run httpexposed --image=katacoda/docker-http-server:latest --replicas=1 --port=80 --hostport=8001
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/httpexposed created
$ curl http://172.17.0.34:8001
<h1>This request was processed by host: httpexposed-68cb8c8d4-7jxl5</h1>
$ kubectl get svc
NAME         TYPE        CLUSTER-IP    EXTERNAL-IP   PORT(S)    AGE
http         ClusterIP   10.99.57.91   172.17.0.34   8000/TCP   5m26s
kubernetes   ClusterIP   10.96.0.1     <none>        443/TCP    21m
$ docker ps | grep httpexposed
305d27b7ef0a        katacoda/docker-http-server   "/app"                   About a minute ago   Up About a minute                          k8s_httpexposed_httpexposed-68cb8c8d4-7jxl5_default_d8535fb7-f2d9-4a50-a4b3-abc5d3166f2e_0
928f66157451        k8s.gcr.io/pause:3.1          "/pause"                 About a minute ago   Up About a minute   0.0.0.0:8001->80/tcp   k8s_POD_httpexposed-68cb8c8d4-7jxl5_default_d8535fb7-f2d9-4a50-a4b3-abc5d3166f2e_0

您应该能够使用它访问它 curl http://172.17.0.34:8001

在幕后，这通过 Docker 端口映射公开了 Pod。因此，您不会看到使用列出的服务kubectl get svc

要查找您可以使用的详细信息 docker ps | grep httpexposed

运行上面的命令，你会注意到端口暴露在 Pod 上，而不是 http 容器本身。Pause 容器负责为 Pod 定义网络。Pod 中的其他容器共享相同的网络命名空间。这提高了网络性能并允许多个容器通过同一网络接口进行通信。

3.5 扩展容器

随着我们的部署运行，我们现在可以使用kubectl来扩展副本的数量。

扩展部署将请求 Kubernetes 启动额外的 Pod。然后，这些 Pod 将使用公开的服务自动进行负载平衡。

kubectl scale命令允许我们调整为特定部署或复制控制器运行的Pod数量。

$ kubectl scale --replicas=3 deployment http
deployment.apps/http scaled

列出所有 pod，您应该会看到三个正在运行的http部署

$ kubectl get pods
NAME                          READY   STATUS    RESTARTS   AGE
http-774bb756bb-b79wn         1/1     Running   0          34s
http-774bb756bb-bspt4         1/1     Running   0          34s
http-774bb756bb-thlz6         1/1     Running   0          12m
httpexposed-68cb8c8d4-7jxl5   1/1     Running   0          4m34s

一旦每个 Pod 启动，它就会被添加到负载均衡器服务中。通过描述服务，您可以查看包含的端点和关联的 Pod。

$ kubectl describe svc http
Name:              http
Namespace:         default
Labels:            run=http
Annotations:       <none>
Selector:          run=http
Type:              ClusterIP
IP:                10.99.57.91
External IPs:      172.17.0.34
Port:              <unset>  8000/TCP
TargetPort:        80/TCP
Endpoints:         172.18.0.4:80,172.18.0.6:80,172.18.0.7:80
Session Affinity:  None
Events:            <none>

向服务发出请求将请求在不同的节点中处理请求。

$ curl http://172.17.0.34:8000
<h1>This request was processed by host: http-774bb756bb-thlz6</h1>

4. YAML 部署容器

在此场景中，您将学习如何使用 Kubectl 创建和启动部署、复制控制器，并通过编写yaml定义通过服务公开它们。

YAML 定义定义了计划部署的 Kubernetes 对象。可以更新对象并将其重新部署到集群以更改配置。

4.1 创建deployment

deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: webapp1
spec:
  replicas: 1
  selector:
    matchLabels:
      app: webapp1
  template:
    metadata:
      labels:
        app: webapp1
    spec:
      containers:
      - name: webapp1
        image: katacoda/docker-http-server:latest
        ports:
        - containerPort: 80

$ kubectl create -f deployment.yaml
deployment.apps/webapp1 created
$ kubectl get deployment
NAME      READY   UP-TO-DATE   AVAILABLE   AGE
webapp1   1/1     1            1           29s
$ kubectl describe deployment webapp1
Name:                   webapp1
Namespace:              default
CreationTimestamp:      Sun, 07 Nov 2021 10:05:15 +0000
Labels:                 <none>
Annotations:            deployment.kubernetes.io/revision: 1
Selector:               app=webapp1
Replicas:               1 desired | 1 updated | 1 total | 1 available | 0 unavailable
StrategyType:           RollingUpdate
MinReadySeconds:        0
RollingUpdateStrategy:  25% max unavailable, 25% max surge
Pod Template:
  Labels:  app=webapp1
  Containers:
   webapp1:
    Image:        katacoda/docker-http-server:latest
    Port:         80/TCP
    Host Port:    0/TCP
    Environment:  <none>
    Mounts:       <none>
  Volumes:        <none>
Conditions:
  Type           Status  Reason
  ----           ------  ------
  Available      True    MinimumReplicasAvailable
  Progressing    True    NewReplicaSetAvailable
OldReplicaSets:  <none>
NewReplicaSet:   webapp1-6b54fb89d9 (1/1 replicas created)
Events:
  Type    Reason             Age   From                   Message
  ----    ------             ----  ----                   -------
  Normal  ScalingReplicaSet  32s   deployment-controller  Scaled up replica set webapp1-6b54fb89d9 to 1

4.2 创建服务

Kubernetes 具有强大的网络功能，可以控制应用程序的通信方式。这些网络配置也可以通过 YAML 进行控制。

service.yaml

apiVersion: v1
kind: Service
metadata:
  name: webapp1-svc
  labels:
    app: webapp1
spec:
  type: NodePort
  ports:
  - port: 80
    nodePort: 30080
  selector:
    app: webapp1

$ kubectl create -f service.yaml
service/webapp1-svc created
$ kubectl get svc
NAME          TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE
kubernetes    ClusterIP   10.96.0.1        <none>        443/TCP        3m3s
webapp1-svc   NodePort    10.107.139.217   <none>        80:30080/TCP   2s
$ kubectl describe svc webapp1-svc
Name:                     webapp1-svc
Namespace:                default
Labels:                   app=webapp1
Annotations:              <none>
Selector:                 app=webapp1
Type:                     NodePort
IP:                       10.107.139.217
Port:                     <unset>  80/TCP
TargetPort:               80/TCP
NodePort:                 <unset>  30080/TCP
Endpoints:                172.18.0.4:80
Session Affinity:         None
External Traffic Policy:  Cluster
Events:                   <none>
$ curl host01:30080
<h1>This request was processed by host: webapp1-6b54fb89d9-hfc88</h1>

4.3 扩容

更改replicas: 4

$ kubectl apply -f deployment.yaml
deployment.apps/webapp1 configured
$ kubectl get deployment
NAME      READY   UP-TO-DATE   AVAILABLE   AGE
webapp1   1/4     4            1           4m27s
$ kubectl get pods
NAME                       READY   STATUS    RESTARTS   AGE
webapp1-6b54fb89d9-hfc88   1/1     Running   0          4m31s
webapp1-6b54fb89d9-j9gdt   1/1     Running   0          6s
webapp1-6b54fb89d9-w7j2w   1/1     Running   0          6s
webapp1-6b54fb89d9-xczm7   1/1     Running   0          6s
$ curl host01:30080
<h1>This request was processed by host: webapp1-6b54fb89d9-hfc88</h1>

kubernetes实战练习1（2）

3. 使用 Kubectl 启动容器

3.1 启动集群

3.2 Kubectl 运行

3.3 Kubectl 暴露

3.4 Kubectl 运行和公开

3.5 扩展容器

4. YAML 部署容器

4.1 创建deployment

4.2 创建服务

4.3 扩容

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