K8s Dashboard和coredns安裝及經常使用命令

一.部署Web UI（Dashboard）
1.解壓包，進入目錄
包就在以前的master部署組件裏
這裏裏面kubernetes-server-linux-amd64.tar.gz

2.執行yaml文件

查看啓動的pod，沒在默認命名空間，在kube-system下

注：
其中dashboard-controller.yaml這個裏面的dashboard鏡像是國外的，若是慢，能夠換成國內的鏡像地址 image: registry.cn-hangzhou.aliyuncs.com/google_containers/kubernetes-dashboard-amd64:v1.10.0

3.建立Dashboard服務

4.查看啓動的Dashboard服務

外網訪問的是端口是44721

5.設置登錄令牌，訪問web界面
建立用戶訪問，綁定集羣管理員，使用它產生的密鑰

建立帳戶產生的token

查看token

複製token到頁面上便可

二.coredns的安裝
安裝coredns的yaml文檔能夠在kubernetes的github上找到https://github.com/kubernetes/kubernetes/edit/master/cluster/addons/dns/coredns/coredns.yaml.sed

[root@master ~]# vim coredns.yaml

# Warning: This is a file generated from the base underscore template file: coredns.yaml.base

apiVersion: v1
kind: ServiceAccount
metadata:
name: coredns
namespace: kube-system
labels:
kubernetes.io/cluster-service: "true"
addonmanager.kubernetes.io/mode: Reconcile

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
labels:
kubernetes.io/bootstrapping: rbac-defaults
addonmanager.kubernetes.io/mode: Reconcile
name: system:coredns
rules:

• apiGroups:
  • ""
    resources:
  • endpoints
  • services
  • pods
  • namespaces
    verbs:
  • list
  • watch
• apiGroups:
  • ""
    resources:
  • nodes
    verbs:

  • get

    apiVersion: rbac.authorization.k8s.io/v1
    kind: ClusterRoleBinding
    metadata:
    annotations:
    rbac.authorization.kubernetes.io/autoupdate: "true"
    labels:
    kubernetes.io/bootstrapping: rbac-defaults
    addonmanager.kubernetes.io/mode: EnsureExists
    name: system:coredns
    roleRef:
    apiGroup: rbac.authorization.k8s.io
    kind: ClusterRole
    name: system:coredns
    subjects:

• kind: ServiceAccount
  name: coredns
  namespace: kube-system

  apiVersion: v1
  kind: ConfigMap
  metadata:
  name: coredns
  namespace: kube-system
  labels:
  addonmanager.kubernetes.io/mode: EnsureExists
  data:
  Corefile: |
  .:53 {
  errors
  health
  kubernetes cluster.local in-addr.arpa ip6.arpa {
  pods insecure
  upstream
  fallthrough in-addr.arpa ip6.arpa
  }
  prometheus :9153
  proxy . /etc/resolv.conf
  cache 30
  loop
  reload
  loadbalance
  }

  apiVersion: extensions/v1beta1
  kind: Deployment
  metadata:
  name: coredns
  namespace: kube-system
  labels:
  k8s-app: kube-dns
  kubernetes.io/cluster-service: "true"
  addonmanager.kubernetes.io/mode: Reconcile
  kubernetes.io/name: "CoreDNS"
  spec:

  replicas: not specified here:

  # 1. In order to make Addon Manager do not reconcile this replicas parameter.
      # 2. Default is 1.
           # 3. Will be tuned in real time if DNS horizontal auto-scaling is turned on.

  strategy:
  type: RollingUpdate
  rollingUpdate:
  maxUnavailable: 1
  selector:
  matchLabels:
  k8s-app: kube-dns
  template:
  metadata:
  labels:
  k8s-app: kube-dns
  annotations:
  seccomp.security.alpha.kubernetes.io/pod: 'docker/default'
  spec:
  serviceAccountName: coredns
  tolerations:

  • key: "CriticalAddonsOnly"
    operator: "Exists"
    containers:
    • name: coredns
      image: coredns/coredns:1.2.6
      imagePullPolicy: IfNotPresent
      resources:
      limits:
      memory: 170Mi
      requests:
      cpu: 100m
      memory: 70Mi
      args: [ "-conf", "/etc/coredns/Corefile" ]
      volumeMounts:
  • name: config-volume
    mountPath: /etc/coredns
    readOnly: true
    ports:
  • containerPort: 53
    name: dns
    protocol: UDP
  • containerPort: 53
    name: dns-tcp
    protocol: TCP
  • containerPort: 9153
    name: metrics
    protocol: TCP
    livenessProbe:
    httpGet:
    path: /health
    port: 8080
    scheme: HTTP
    initialDelaySeconds: 60
    timeoutSeconds: 5
    successThreshold: 1
    failureThreshold: 5
    securityContext:
    allowPrivilegeEscalation: false
    capabilities:
    add:
    • NET_BIND_SERVICE
      drop:
    • all
      readOnlyRootFilesystem: true
      dnsPolicy: Default
      volumes:
  • name: config-volume
    configMap:
    name: coredns
    items:

    • key: Corefile
      path: Corefile

      apiVersion: v1
      kind: Service
      metadata:
      name: kube-dns
      namespace: kube-system
      annotations:
      prometheus.io/port: "9153"
      prometheus.io/scrape: "true"
      labels:
      k8s-app: kube-dns
      kubernetes.io/cluster-service: "true"
      addonmanager.kubernetes.io/mode: Reconcile
      kubernetes.io/name: "CoreDNS"
      spec:
      selector:
      k8s-app: kube-dns
      clusterIP: 10.0.0.2
      ports:

      • name: dns
        port: 53
        protocol: UDP
      • name: dns-tcp
        port: 53
        protocol: TCP

1.部署coredns

2.查看部署dns結果
[root@master ~]# kubectl get pods -n kube-system

3.測試能夠解析到集羣裏的服務

不一樣命名空間解析
後面加上命名空間.svc.cluster.local

三.kubectl管理工具

1.刪除
先刪除控制器，再刪服務

[root@master ~]# kubectl delete deployment.apps/nginx
[root@master ~]# kubectl delete service/nginx

2.在默認命名空間下建立nginx容器
[root@master ~]# kubectl run nginx --image=nginx --replicas=3 --labels="app=nignx-example" --image=nginx:1.10 --port=80
查看pod
[root@master ~]# kubectl get all

3.查看pod的詳細信息describe
[root@master ~]# kubectl describe pod/nginx-7cfb59d88d-nmtp9

下面還有事件，能夠用於排錯

4.查看pod和service
[root@master ~]# kubectl get pod
[root@master ~]# kubectl get svc

5.顯示標籤
[root@master ~]# kubectl get pods --show-labels

注：設置標籤的好處，到時候pod多了，能夠指定pod的標籤查找

6.查詢pod的詳細信息
[root@master ~]# kubectl get pods -o wide

7.查看控制用到的那些鏡像
[root@master ~]# kubectl get deployment -o wide

8.啓動發佈服務
[root@master ~]# kubectl expose deployment nginx --port=88 --type=NodePort --target-port=80 --name=nginx-service

expose暴露服務
--port=88 外部ba暴露端口
type=NodePort 使用節點端口訪問應用
--target-port=80 內部端口
--name=nginx-service 服務名稱

經過集羣ip加外部暴露端口能夠在任意節點訪問應用

或者經過node端口和節點地址地址訪問

四.故障排查
1.查看pod詳細信息
kubectl describe 容器pod id

2.查看pod日誌
kubectl log 容器pod id

3.進入到pod查看狀況
kubectl exec -it pod id bash

五.更新鏡像
kubectl set --help 這個命令更新設置容器的設置
1.更新鏡像版本

將以前的nginx1.10跟新爲nginx1.11版本

這個過程是將以前的1.10版本的3個鏡像刪除，在建立3個1.11版本的鏡像

查看剛建立的pod詳細信息，已經變成nginx:1.11
[root@master ~]# kubectl describe pod nginx-799f6b8cfc-khbvf

2.還有另外一種的辦法更新鏡像，直接編輯控制器資源文件
[root@master ~]# kubectl edit deploy/nginx

查看新建立的pod信息顯示image是nginx:1.12

3.能夠查看版本歷史
[root@master ~]# kubectl rollout status deploy/nginx
[root@master ~]# kubectl rollout history deploy/nginx
再次升級爲nginx:1.13

更新完成

history能夠查看以前的記錄

4.回滾狀態
如今版本是nginx:1.13,假設這個版本有問題，要根據history回滾到以前的版本

[root@master ~]# kubectl rollout undo deployment.apps/nginx
[root@master ~]# kubectl rollout status deploy/nginx

查看版本歷史，少了第三個版本，已經回滾到nginx:1.12了

查看新pod詳細信息已是1.12了

六.擴容副本scale
因爲高併發業務須要將後端pod擴展爲5個（如今爲3個）
[root@master ~]# kubectl scale deployment.apps/nginx --replicas=5

業務下來了還能夠縮容