1. k8s的yaml文件到底有多复杂

Kubernetes创建、更新、删除资源等操作时均可以使用json或yaml文件进行操作，更新和删除可以依赖之前的文件进行更改，但是创建具有多变形，往往编辑起来比较复杂，容器出错，而且k8s的配置项实在太多，稍微不注意就会犯错。要写好一个yaml文件，你需要了解yaml的语法，需要掌握k8s的各种配置，对于一个k8s的初学者而言，这将是一件很难的事情。

 

比如我们看一个同时创建一个Deployment、Service、Ingress的yaml文件内容：

---

apiVersion: v1

kind: Service

metadata:

  labels:

    app: test-yaml

  name: test-yaml

  namespace: freeswitch

spec:

  ports:

  - name: container-1-web-1

    port: 8080

    protocol: TCP

    targetPort: 8080

  selector:

    app: test-yaml

  sessionAffinity: None

  type: ClusterIP

---

apiVersion: networking.k8s.io/v1beta1

kind: Ingress

metadata:

  creationTimestamp: null

  name: test-yaml

spec:

  rules:

  - host: test.com

    http:

      paths:

      - backend:

          serviceName: test-yaml

          servicePort: 8080

        path: /

---

apiVersion: apps/v1

kind: Deployment

metadata:

  labels:

    app: test-yaml

  name: test-yaml

  namespace: freeswitch

spec:

  replicas: 3

  selector:

    matchLabels:

      app: test-yaml

  strategy:

    rollingUpdate:

      maxSurge: 1

      maxUnavailable: 0

    type: RollingUpdate

  template:

    metadata:

      annotations:

        info: test for yaml

      labels:

        app: test-yaml

    spec:

      affinity:

        podAntiAffinity:

          preferredDuringSchedulingIgnoredDuringExecution:

          - podAffinityTerm:

              labelSelector:

                matchExpressions:

                - key: app

                  operator: In

                  values:

                  - test-yaml

              topologyKey: kubernetes.io/hostname

            weight: 100

      containers:

      - env:

        - name: TZ

          value: Asia/Shanghai

        - name: LANG

          value: C.UTF-8

        image: nginx

        imagePullPolicy: Always

        lifecycle: {}

        livenessProbe:

          failureThreshold: 2

          initialDelaySeconds: 30

          periodSeconds: 10

          successThreshold: 1

          tcpSocket:

            port: 8080

          timeoutSeconds: 2

        name: test-yaml

        ports:

        - containerPort: 8080

          name: web

          protocol: TCP

        readinessProbe:

          failureThreshold: 2

          initialDelaySeconds: 30

          periodSeconds: 10

          successThreshold: 1

          tcpSocket:

            port: 8080

          timeoutSeconds: 2

        resources:

          limits:

            cpu: 195m

            memory: 375Mi

          requests:

            cpu: 10m

            memory: 10Mi

        securityContext:

          allowPrivilegeEscalation: false

          capabilities: {}

          privileged: false

          procMount: Default

          readOnlyRootFilesystem: false

          runAsNonRoot: false

        volumeMounts:

        - mountPath: /usr/share/zoneinfo/Asia/Shanghai

          name: tz-config

        - mountPath: /etc/localtime

          name: tz-config

        - mountPath: /etc/timezone

          name: timezone

      dnsPolicy: ClusterFirst

      hostAliases:

      - hostnames:

        - www.baidu.com

        ip: 114.114.114.114

      imagePullSecrets:

      - name: myregistrykey

      - name: myregistrykey2

      restartPolicy: Always

      securityContext: {}

      volumes:

      - hostPath:

          path: /usr/share/zoneinfo/Asia/Shanghai

          type: ""

        name: tz-config

      - hostPath:

          path: /etc/timezone

          type: ""

        name: timezone

这是一个包含了Service、Ingress、Deployment比较常用并且没有用到高级功能的yaml配置，就已经有上百行，如果是在添加了一些高级配置或者是Deployment中的容器不止一个，这个yaml会更大，就会造成一种视觉上疲劳，更改起来也比较麻烦而且非常容易出错。

 

2. 基于图形化的方式自动生成yaml

 

2.1 k8s图形化管理工具Ratel安装

 

本次采用Ratel自动生成yaml文件，Ratel安装文档：https://github.com/dotbalo/ratel-doc/blob/master/cluster/Install.md请添加链接描述

 

2.2 使用Ratel创建生成yaml文件

 

2.2.1 基本配置

 

安装完成后，可以生成、创建管理常用的k8s核心资源，比如创建一个Deployment：

点击Deployment -- 创建如图所示：

 

之后可以填写一些基本的配置信息，比如Deployment名称、副本数、标签信息等，当然也可以点击必须/尽量部署至不同宿主机进行Pod亲和力的配置

 

同时也可添加一些复杂的配置，比如内核配置、容忍配置、节点亲和力快捷配置：

 

2.2.2 亲和力配置

 

基本配置编译完成以后，点击NEXT，下一个配置亲和力配置，如果上一页使用了亲和力快捷键，这边会自动生成亲和力配置，你可以再次编辑或者添加、删除：

 

2.2.3 存储配置

 

亲和力配置完成以后，可以点击NEXT进行存储配置，目前支持volume和projectedVolume配置，volume支持configMap、Secret、HostPath、PVC、NFS、Empty等常用类型的配置：

 

2.2.4 容器配置

 

接下来是容器配置，支持常用的容器配置，当然也可以添加多个容器：

 

稍微复制一点的配置：

 

2.2.4 初始化容器配置

 

初始化容器和容器配置类似

 

2.2.5 Service和Ingress配置

 

创建Deployment时可以一键添加Service和Ingress，添加Service时会自动读取容器的端口配置，添加Ingress时会自动读取Service配置

 

2.2.6 创建资源或生成yaml文件

 

上述配置完成以后，可以选择创建资源或生成yaml文件，假如点击生成yaml文件，会自动生成Service、Ingress、Deployment的yaml文件，可以直接拿着使用：

 

生成的内容如下：

---

apiVersion: v1

kind: Service

metadata:

  creationTimestamp: null

  labels:

    app: test-yaml

  name: test-yaml

  namespace: default

spec:

  ports:

  - name: container-1-web-1

    port: 8080

    protocol: TCP

    targetPort: 8080

  selector:

    app: test-yaml

  sessionAffinity: None

  type: ClusterIP

status:

  loadBalancer: {}

---

apiVersion: networking.k8s.io/v1beta1

kind: Ingress

metadata:

  creationTimestamp: null

  name: test-yaml

spec:

  rules:

  - host: test.com

    http:

      paths:

      - backend:

          serviceName: test-yaml

          servicePort: 8080

        path: /

status:

  loadBalancer: {}

---

apiVersion: apps/v1

kind: Deployment

metadata:

  creationTimestamp: null

  labels:

    app: test-yaml

  name: test-yaml

  namespace: default

spec:

  replicas: 3

  selector:

    matchLabels:

      app: test-yaml

  strategy:

    rollingUpdate:

      maxSurge: 1

      maxUnavailable: 0

    type: RollingUpdate

  template:

    metadata:

      creationTimestamp: null

      labels:

        app: test-yaml

    spec:

      affinity:

        nodeAffinity:

          preferredDuringSchedulingIgnoredDuringExecution:

          - preference:

              matchExpressions:

              - key: loki

                operator: In

                values:

                - "true"

            weight: 100

          requiredDuringSchedulingIgnoredDuringExecution:

            nodeSelectorTerms:

            - matchExpressions:

              - key: master

                operator: NotIn

                values:

                - "true"

        podAntiAffinity:

          requiredDuringSchedulingIgnoredDuringExecution:

          - labelSelector:

              matchExpressions:

              - key: app

                operator: In

                values:

                - test-yaml

            topologyKey: kubernetes.io/hostname

      containers:

      - args:

        - '*.jar --server.port=80'

        command:

        - java -jar

        env:

        - name: TZ

          value: Asia/Shanghai

        - name: LANG

          value: C.UTF-8

        - name: POD_IP

          valueFrom:

            fieldRef:

              fieldPath: status.podIP

        envFrom:

        - configMapRef:

            name: testcm

        image: nginx

        imagePullPolicy: IfNotPresent

        lifecycle:

          postStart:

            exec:

              command:

              - echo "start"

          preStop:

            exec:

              command:

              - sleep 30

        livenessProbe:

          failureThreshold: 2

          initialDelaySeconds: 30

          periodSeconds: 10

          successThreshold: 1

          tcpSocket:

            port: 8080

          timeoutSeconds: 2

        name: test-yaml

        ports:

        - containerPort: 8080

          name: web

          protocol: TCP

        readinessProbe:

          failureThreshold: 2

          httpGet:

            httpHeaders:

            - name: a

              value: b

            path: /

            port: 8080

            scheme: HTTP

          initialDelaySeconds: 30

          periodSeconds: 10

          successThreshold: 1

          timeoutSeconds: 2

        resources:

          limits:

            cpu: 493m

            memory: 622Mi

          requests:

            cpu: 10m

            memory: 10Mi

        securityContext:

          allowPrivilegeEscalation: false

          capabilities: {}

          privileged: false

          procMount: Default

          readOnlyRootFilesystem: false

          runAsNonRoot: false

        volumeMounts:

        - mountPath: /usr/share/zoneinfo/Asia/Shanghai

          name: tz-config

        - mountPath: /etc/localtime

          name: tz-config

        - mountPath: /etc/timezone

          name: timezone

        - mountPath: /mnt

          name: nfs-test

      dnsPolicy: ClusterFirst

      initContainers:

      - args:

        - init

        command:

        - echo

        env:

        - name: TZ

          value: Asia/Shanghai

        - name: LANG

          value: C.UTF-8

        image: nignx-init

        imagePullPolicy: Always

        name: init

        resources:

          limits:

            cpu: 351m

            memory: 258Mi

          requests:

            cpu: 10m

            memory: 10Mi

        securityContext:

          allowPrivilegeEscalation: false

          capabilities: {}

          privileged: false

          procMount: Default

          readOnlyRootFilesystem: false

          runAsNonRoot: false

        volumeMounts:

        - mountPath: /usr/share/zoneinfo/Asia/Shanghai

          name: tz-config

        - mountPath: /etc/localtime

          name: tz-config

        - mountPath: /etc/timezone

          name: timezone

      nodeSelector:

        ratel: "true"

      restartPolicy: Always

      securityContext:

        sysctls:

        - name: net.core.somaxconn

          value: "16384"

        - name: net.ipv4.tcp_max_syn_backlog

          value: "16384"

      tolerations:

      - effect: NoSchedule

        key: node-role.kubernetes.io/master

        operator: Exists

      volumes:

      - name: projected-test

        projected:

          defaultMode: 420

          sources:

          - downwardAPI:

              items:

              - fieldRef:

                  fieldPath: metadata.name

                path: /opt/x

      - hostPath:

          path: /usr/share/zoneinfo/Asia/Shanghai

          type: ""

        name: tz-config

      - hostPath:

          path: /etc/timezone

          type: ""

        name: timezone

      - name: nfs-test

        nfs:

          path: /data/nfs

          server: 1.1.1.1

status: {}

这个yaml比之前的稍复杂，并且添加了一些高级配置，手动编写的还是比较麻烦的，所以用Ratel自动生成还是比较方便的，并且不会出错。

 

3. 其他资源文件自动生成

 

目前支持了很多资源文件的自动生成，比如：Deployment、StatefulSet、DaemonSet、Service、Ingress、CronJob、Secret、ConfigMap、PV、PVC等，可以大大减少我们的工作量和k8s的复杂度。

 

 

如果想要系统的学习k8s，可以专注下k8s的课程：

51CTO

 

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