1.常用命令

1.1基础

• 执行/更新配置

kubectl apply -f <file.yml>

• 列表查看
  -o wide 可以查看详细信息

kubectl get <type> [-n <namespace-name>] <name> [-o wide] [-w]

参数	作用
n	指定namespace，默认是default
o	指定展示方式，wide意思是宽表
w	类似tail命令中的f参数，跟随变更

• 查看详情

kubectl describe <type> <name>

• 删除
  注意删除控制器的时候默认删除关联的Pod，可以通过添加命令–cascade=false表示不删除

kubectl delete <type> <name> [--cascade=false] [-l label.key=label.value]

参数	功能说明
cascade	是否删除控制器关联的Pod，true表示删除，默认true
l	依据标签执行，后面跟的是标签的key和value

• 给节点添加标签

kubectl label nodes <node-name> {key=value}

key=value，key是标签的key，value是标签的value

• 查看节点标签

kubectl label node <node-name> --list=true

1.2 Deployment控制器

• 查看deployment控制器

kubectl get deployments

• 删除deployment控制器

kubectl delete deployments <deployments-name> [--cascade=false]

• 版本升级
  建议修改配置文件，使用apply命令更新
• 回滚至前一版

kubectl rollout undo deployment/<deployment-name>

• 查看历史版本

kubectl rollout history deployment/<deployment-name> [--to-revision=1]

参数	功能说明
to-revision	回滚到指定版本，值是版本序号

• 更新到指定版本

kubectl rollout history deployment/<deployment-name> [--revision=1]

参数	功能说明
revision	查看指定版本的详细信息，值是版本序号

• 扩缩容

kubectl scale deployment <deployment-name> --replicas=4

参数	功能说明
replicas	副本数量

1.3 Pod

• 查看Pod

kubectl get pod -o wide

• 删除Pod

kubectl delete pod <pod-name>

• 查看Pod版本号

kubectl get pods -o custom-columns=Name:metadata.name,Image:spec.containers[0].image

1.4 ReplicaSet控制器

• 查看ReplicaSet控制器

kubectl get rs

• 删除

kubectl delete replicasets <rs-name> [--cascade=false]

1.5 HPA控制器

• 这个需要先启动deployment控制器，再启动响应的hpa控制器。
• 查看所有

kubectl get hpa <hpa-name> -o wide

• 删除

kubectl delete hpa <hpa-name>

1.6 节点调度

• 当节点处于不可调度状态时执行

kubectl uncordon <node-name>

2. 配置举例

2.1 简单Demo

• 使用Deployment控制器
• Pod数量为2
• nginx开放端口80
• 设置调度要求，调度在标签有dev的节点上。
• 设置调度要求，调度到指定节点。
• 调度一般是对设备的物理属性有要求，比如mysql容器等等。

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
spec:
  replicas: 2 #指定Pod数量为2
  selector:
    matchLabels:
        app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      #nodeSelector:
        #env: dev # 节点调度到开发环境
      #nodeName: master #指定调度节点为master
      containers:
      - name: nginx
        image: nginx:1.12
        ports:
        - containerPort: 80 #开放端口

2.2 设置版本更新策略

• 使用Deployment控制器
• 版本更新策略为滚动更新

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
spec:
  replicas: 2
  minReadySeconds: 2  # 这里需要估一个比较合理的值，从容器启动到应用正常提供服务
  strategy:  # k8s 默认的 strategy 就是 RollingUpdate， 这里写明出来可以调节细节参数
    #type: Recreate
    type: RollingUpdate
    rollingUpdate:
      maxSurge: 1  # 更新时允许最大激增的容器数，默认 replicas 的 1/4 向上取整
      maxUnavailable: 0  # 更新时允许最大 unavailable 容器数，默认 replicas 的 1/4 向下取整
  selector:
    matchLabels:
        app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.20
        ports:
        - containerPort: 80

2.3 简单的HPA控制器

• 控制CPU核数
• pod配置内存要求

HPA控制器

apiVersion: autoscaling/v2beta2
kind: HorizontalPodAutoscaler
metadata:
  name: cpu-nginx-demo
spec:
  minReplicas: 1  #最小pod数量
  maxReplicas: 10 #最大pod数量
  scaleTargetRef:   # 指定要控制的nginx信息
    apiVersion: apps/v1
    kind: Deployment
    name: nginx-demo
  metrics:  # 指定内存的一个配置
  - type: Resource
    resource:
      name: memory
      target:
        type: Utilization
        averageUtilization: 10  #当整体的资源利用率超过这个百分比的时候，会进行扩容

pod

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-demo
spec:
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.12
        ports:
        - containerPort: 80
        resources:
          requests:
            memory: 50Mi
            cpu: 50m
          limits:
            memory: 100Mi
            cpu: 100m

2.4 emptyDir Demo

• Pod中定义一个html位置，容器匹配对应位置。
• 多容器可以读取同一位置中的文件。
• 重启Pod后数据消失。

apiVersion: apps/v1
kind: Deployment
metadata:
  name: vol-emptydir-deploy
spec:
  replicas: 1
  selector:
    matchLabels:
        app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      volumes:    #定义存储卷
        - name: html    #定义存储卷的名称
          emptyDir: {}    #定义存储卷的类型
      containers:
      - name: nginx
        image: nginx:1.12
        ports:
        - containerPort: 80
        volumeMounts:    #在容器中定义挂载存储卷的名和路径
        - name: html
          mountPath: /usr/share/nginx/html

2.5 hostpath Demo

• Pod中定义一个html位置，容器匹配对应位置。
• 重启Pod后数据不会消失。

apiVersion: apps/v1
kind: Deployment
metadata:
  name: vol-hostpath-deploy
spec:
  replicas: 1
  selector:
    matchLabels:
        app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      volumes:    #定义存储卷
      - name: html # 定义存储名称
        hostPath:  # 定义存储类型
          path: /tmp/k8s/data/volumn # 宿主机存储路径
          type: DirectoryOrCreate     # 不存在路径创建路径
      containers:
      - name: nginx
        image: nginx:1.12
        ports:
        - containerPort: 80
        volumeMounts:    #在容器中定义挂载存储卷的名和路径
        - name: html
          mountPath: /usr/share/nginx/html

3. 组件安装

3.1 配套HPA控制器的Metrics-server

• 下载资源清单

wget https://github.com/kubernetes-sigs/metrics-server/releases/latest/download/components.yaml

• 变更镜像地址

image: bitnami/metrics-server:0.6.2

• 跳过证书校验

--kubelet-insecure-tls

• 最终文件

apiVersion: v1
kind: ServiceAccount
metadata:
  labels:
    k8s-app: metrics-server
  name: metrics-server
  namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  labels:
    k8s-app: metrics-server
    rbac.authorization.k8s.io/aggregate-to-admin: "true"
    rbac.authorization.k8s.io/aggregate-to-edit: "true"
    rbac.authorization.k8s.io/aggregate-to-view: "true"
  name: system:aggregated-metrics-reader
rules:
- apiGroups:
  - metrics.k8s.io
  resources:
  - pods
  - nodes
  verbs:
  - get
  - list
  - watch
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  labels:
    k8s-app: metrics-server
  name: system:metrics-server
rules:
- apiGroups:
  - ""
  resources:
  - nodes/metrics
  verbs:
  - get
- apiGroups:
  - ""
  resources:
  - pods
  - nodes
  verbs:
  - get
  - list
  - watch
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  labels:
    k8s-app: metrics-server
  name: metrics-server-auth-reader
  namespace: kube-system
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: extension-apiserver-authentication-reader
subjects:
- kind: ServiceAccount
  name: metrics-server
  namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  labels:
    k8s-app: metrics-server
  name: metrics-server:system:auth-delegator
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: system:auth-delegator
subjects:
- kind: ServiceAccount
  name: metrics-server
  namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  labels:
    k8s-app: metrics-server
  name: system:metrics-server
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: system:metrics-server
subjects:
- kind: ServiceAccount
  name: metrics-server
  namespace: kube-system
---
apiVersion: v1
kind: Service
metadata:
  labels:
    k8s-app: metrics-server
  name: metrics-server
  namespace: kube-system
spec:
  ports:
  - name: https
    port: 443
    protocol: TCP
    targetPort: https
  selector:
    k8s-app: metrics-server
---
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    k8s-app: metrics-server
  name: metrics-server
  namespace: kube-system
spec:
  selector:
    matchLabels:
      k8s-app: metrics-server
  strategy:
    rollingUpdate:
      maxUnavailable: 0
  template:
    metadata:
      labels:
        k8s-app: metrics-server
    spec:
      containers:
      - args:
        - --cert-dir=/tmp
        - --secure-port=4443
        - --kubelet-preferred-address-types=InternalIP,ExternalIP,Hostname
        - --kubelet-use-node-status-port
        - --kubelet-insecure-tls
        - --metric-resolution=15s
        image: bitnami/metrics-server:0.6.2
        imagePullPolicy: IfNotPresent
        livenessProbe:
          failureThreshold: 3
          httpGet:
            path: /livez
            port: https
            scheme: HTTPS
          periodSeconds: 10
        name: metrics-server
        ports:
        - containerPort: 4443
          name: https
          protocol: TCP
        readinessProbe:
          failureThreshold: 3
          httpGet:
            path: /readyz
            port: https
            scheme: HTTPS
          initialDelaySeconds: 20
          periodSeconds: 10
        resources:
          requests:
            cpu: 100m
            memory: 200Mi
        securityContext:
          allowPrivilegeEscalation: false
          readOnlyRootFilesystem: true
          runAsNonRoot: true
          runAsUser: 1000
        volumeMounts:
        - mountPath: /tmp
          name: tmp-dir
      nodeSelector:
        kubernetes.io/os: linux
      priorityClassName: system-cluster-critical
      serviceAccountName: metrics-server
      volumes:
      - emptyDir: {}
        name: tmp-dir
---
apiVersion: apiregistration.k8s.io/v1
kind: APIService
metadata:
  labels:
    k8s-app: metrics-server
  name: v1beta1.metrics.k8s.io
spec:
  group: metrics.k8s.io
  groupPriorityMinimum: 100
  insecureSkipTLSVerify: true
  service:
    name: metrics-server
    namespace: kube-system
  version: v1beta1
  versionPriority: 100

• 查看指标

kubectl top node

• 查看所有指标

kubectl top pod --all-namespaces