K8S资源管理总结及dashboard创建

K8S核心资源管理方法：

陈述式管理：基于众多kubectl命令
声明式管理：基于k8s资源配置清单
GUI式管理：基于K8S仪表盘（dashboard）

K8S四种核心的附件

CNI网络插件：如果集群足够小，其实不需要网络插件，只需要改iptables规则，增加几条路由就可以了。

在恰当的时候，用恰当的技术，解决恰当的问题。

CNI网络插件
- flannel（在100台机器的规模内）
- 三种常用工作模式
  - NAT
  - VxLAN
- 优化SNAT规则（集群内容器通信，能获取到具体的容器IP，而不是宿主机IP）
K8S的服务发现
- 集群网络：clusterIP
- Service资源：Service Name
- CoreDNS软件：实现了Service Name和Cluster IP的自动关联
K8S的服务暴露
- Ingress资源：专用于暴露7层应用到K8S集群外的一种核心资源（http/https）
- ingress controller：一个简化版的nginx（调度流量）+go脚本（动态识别yaml）
- Traefik软件：实现了ingress控制器的一个软件
GUI图形化管理插件

开始安装dashboard

在运维主机上hdss7-200

[root@hdss7-200 k8s-yaml]# docker pull k8scn/kubernetes-dashboard-amd64:v1.8.3
[root@hdss7-200 k8s-yaml]# docker images | grep dashboard
k8scn/kubernetes-dashboard-amd64   v1.8.3     fcac9aa03fd6     2 years ago         102MB
[root@hdss7-200 k8s-yaml]# docker tag fcac9aa03fd6 harbor.od.com/public/dashboard.od.com:v1.8.3
[root@hdss7-200 k8s-yaml]# docker push !$

rbac.yaml

apiVersion: v1
kind: ServiceAccount
metadata:
  labels:
    k8s-app: kubernetes-dashboard
    addonmanager.kubernetes.io/mode: Reconcile
  name: kubernetes-dashboard-admin
  namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: kubernetes-dashboard-admin
  namespace: kube-system
  labels:
    k8s-app: kubernetes-dashboard
    addonmanager.kubernetes.io/mode: Reconcile
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: cluster-admin
subjects:
- kind: ServiceAccount
  name: kubernetes-dashboard-admin
  namespace: kube-system

dp.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: kubernetes-dashboard
  namespace: kube-system
  labels:
    k8s-app: kubernetes-dashboard
    kubernetes.io/cluster-service: "true"
    addonmanager.kubernetes.io/mode: Reconcile
spec:
  selector:
    matchLabels:
      k8s-app: kubernetes-dashboard
  template:
    metadata:
      labels:
        k8s-app: kubernetes-dashboard
      annotations:
        scheduler.alpha.kubernetes.io/critical-pod: ''
    spec:
      priorityClassName: system-cluster-critical
      containers:
      - name: kubernetes-dashboard
        image: harbor.od.com/public/dashboard:v1.8.3
        resources:
          limits:
            cpu: 100m
            memory: 300Mi
          requests:
            cpu: 50m
            memory: 100Mi
        ports:
        - containerPort: 8443
          protocol: TCP
        args:
          # PLATFORM-SPECIFIC ARGS HERE
          - --auto-generate-certificates
        volumeMounts:
        - name: tmp-volume
          mountPath: /tmp
        livenessProbe:
          httpGet:
            scheme: HTTPS
            path: /
            port: 8443
          initialDelaySeconds: 30
          timeoutSeconds: 30
      volumes:
      - name: tmp-volume
        emptyDir: {}
      serviceAccountName: kubernetes-dashboard-admin
      tolerations:
      - key: "CriticalAddonsOnly"
        operator: "Exists"

          - --auto-generate-certificates
          # 自动生成证书
          livenessProbe:
          # 容器存活性探针
          # 容器就绪性探针
          # 目标是判定容器在K8S容器编排环境下是否正常启动，或者运行的过程中是否有异常退出
          # 就绪性探针
          # 容器被拉起来之后，先用就绪性探针去探测它，直到它满足我的要求，我认定它为就绪状态，就是running状态
            port: 8443
            # 监听8443是否存在，存在则说明容器是正常状态

svc.yaml

apiVersion: v1
kind: Service
metadata:
  name: kubernetes-dashboard
  namespace: kube-system
  labels:
    k8s-app: kubernetes-dashboard
    kubernetes.io/cluster-service: "true"
    addonmanager.kubernetes.io/mode: Reconcile
spec:
  selector:
    k8s-app: kubernetes-dashboard
  ports:
  - port: 443
    targetPort: 8443

ingress.yaml

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: kubernetes-dashboard
  namespace: kube-system
  annotations:
    kubernetes.io/ingress.class: traefik
spec:
  rules:
  - host: dashboard.od.com
    http:
      paths:
      - backend:
          serviceName: kubernetes-dashboard
          servicePort: 443

创建资源

[root@hdss7-22 ~]# kubectl apply -f http://k8s-yaml.od.com/dashboard/rbac.yaml
serviceaccount/kubernetes-dashboard-admin created
clusterrolebinding.rbac.authorization.k8s.io/kubernetes-dashboard-admin created

[root@hdss7-22 ~]# kubectl apply -f http://k8s-yaml.od.com/dashboard/dp.yaml
deployment.apps/kubernetes-dashboard created

[root@hdss7-22 ~]# kubectl apply -f http://k8s-yaml.od.com/dashboard/svc.yaml
service/kubernetes-dashboard created

[root@hdss7-22 ~]# kubectl apply -f http://k8s-yaml.od.com/dashboard/ingress.yaml
ingress.extensions/kubernetes-dashboard created

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