kubernetes 配置kubedns

一、下载镜像
[root@k8s_master ~]# docker pull ist0ne/kubedns-amd64
[root@k8s_master ~]# docker pull ist0ne/k8s-dns-dnsmasq-amd64
[root@k8s_master ~]# docker pull ist0ne/dnsmasq-metrics-amd64
[root@k8s_master ~]# docker pull ist0ne/exechealthz-amd64

二、下载配置文件
通过https://rawgit.com这个地址加速下载,下载为skydns-rc.yaml和skydns-svc.yaml文件名

wget https://rawgit.com/kubernetes/kubernetes/release-1.5/cluster/addons/dns/skydns-rc.yaml.sed -O skydns-rc.yaml
wget https://rawgit.com/kubernetes/kubernetes/release-1.5/cluster/addons/dns/skydns-svc.yaml.sed -O skydns-svc.yaml

三、修改配置文件:
修改skydns-rc.yaml,其中images修改成,步骤一已下载的镜像,domain修改

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: kube-dns
  namespace: kube-system
  labels:
    k8s-app: kube-dns
    kubernetes.io/cluster-service: "true"
spec:
  #指定副本数
  replicas: 1
  # 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:
    rollingUpdate:
      maxSurge: 10%
      maxUnavailable: 0
  selector:
    matchLabels:
      k8s-app: kube-dns
  template:
    metadata:
      labels:
        k8s-app: kube-dns
      annotations:
        scheduler.alpha.kubernetes.io/critical-pod: ''
        scheduler.alpha.kubernetes.io/tolerations: '[{"key":"CriticalAddonsOnly", "operator":"Exists"}]'
    spec:
      containers:
      - name: kubedns
        image: docker.io/ist0ne/kubedns-amd64:latest
        resources:
          # TODO: Set memory limits when we've profiled the container for large
          # clusters, then set request = limit to keep this container in
          # guaranteed class. Currently, this container falls into the
          # "burstable" category so the kubelet doesn't backoff from restarting it.
          limits:
            memory: 170Mi
          requests:
            cpu: 100m
            memory: 70Mi
        livenessProbe:
          httpGet:
            path: /healthz-kubedns
            port: 8080
            scheme: HTTP
          initialDelaySeconds: 60
          timeoutSeconds: 5
          successThreshold: 1
          failureThreshold: 5
        readinessProbe:
          httpGet:
            path: /readiness
            port: 8081
            scheme: HTTP
          # we poll on pod startup for the Kubernetes master service and
          # only setup the /readiness HTTP server once that's available.
          initialDelaySeconds: 3
          timeoutSeconds: 5
        args:
        #指定一级域名
        - --domain=huangzai.com.
        - --dns-port=10053
        - --config-map=kube-dns
        #增加kube-master-url,指向k8s_master地址
        - --kube-master-url=http://192.168.3.216:8080
        # This should be set to v=2 only after the new image (cut from 1.5) has
        # been released, otherwise we will flood the logs.
        - --v=0
        env:
        - name: PROMETHEUS_PORT
          value: "10055"
        ports:
        - containerPort: 10053
          name: dns-local
          protocol: UDP
        - containerPort: 10053
          name: dns-tcp-local
          protocol: TCP
        - containerPort: 10055
          name: metrics
          protocol: TCP
      - name: dnsmasq
        image: docker.io/ist0ne/k8s-dns-dnsmasq-amd64:latest
        livenessProbe:
          httpGet:
            path: /healthz-dnsmasq
            port: 8080
            scheme: HTTP
          initialDelaySeconds: 60
          timeoutSeconds: 5
          successThreshold: 1
          failureThreshold: 5
        args:
        - --cache-size=1000
        - --no-resolv
        - --server=127.0.0.1#10053
        #注释掉
        #- --log-facility=-
        ports:
        - containerPort: 53
          name: dns
          protocol: UDP
        - containerPort: 53
          name: dns-tcp
          protocol: TCP
        # see: https://github.com/kubernetes/kubernetes/issues/29055 for details
        resources:
          requests:
            cpu: 150m
            memory: 10Mi
      - name: dnsmasq-metrics
        image: docker.io/ist0ne/dnsmasq-metrics-amd64:latest
        livenessProbe:
          httpGet:
            path: /metrics
            port: 10054
            scheme: HTTP
          initialDelaySeconds: 60
          timeoutSeconds: 5
          successThreshold: 1
          failureThreshold: 5
        args:
        - --v=2
        - --logtostderr
        ports:
        - containerPort: 10054
          name: metrics
          protocol: TCP
        resources:
          requests:
            memory: 10Mi
      - name: healthz
        image: docker.io/ist0ne/exechealthz-amd64:latest
        resources:
          limits:
            memory: 50Mi
          requests:
            cpu: 10m
            # Note that this container shouldn't really need 50Mi of memory. The
            # limits are set higher than expected pending investigation on #29688.
            # The extra memory was stolen from the kubedns container to keep the
            # net memory requested by the pod constant.
            memory: 50Mi
        args:
        - --cmd=nslookup kubernetes.default.svc.huangzai.com 127.0.0.1 >/dev/null
        - --url=/healthz-dnsmasq
        - --cmd=nslookup kubernetes.default.svc.huangzai.com 127.0.0.1:10053 >/dev/null
        - --url=/healthz-kubedns
        - --port=8080
        - --quiet
        ports:
        - containerPort: 8080
          protocol: TCP
      dnsPolicy: Default  # Don't use cluster DNS.

修改skydns-svc.yaml,指定clusterIP,可任意。Node各pod的dns地址都会指向该DNS地址

apiVersion: v1
kind: Service
metadata:
  name: kube-dns
  namespace: kube-system
  labels:
    k8s-app: kube-dns
    kubernetes.io/cluster-service: "true"
    kubernetes.io/name: "KubeDNS"
spec:
  selector:
    k8s-app: kube-dns
  clusterIP: 10.254.0.100
  ports:
  - name: dns
    port: 53
    protocol: UDP
  - name: dns-tcp
    port: 53
    protocol: TCP

四、启动DNS
[root@k8s_master ~]# kubectl create -f skydns-rc.yaml
deployment "kube-dns" created
[root@k8s_master ~]# kubectl create -f skydns-svc.yaml
service "kube-dns" created

五、修改Node上的 /etc/kubernetes/kubelet配置,增加如下内容
[root@k8s_client1 ~]# vim /etc/kubernetes/kubelet

KUBELET_ARGS="--cluster_dns=10.254.0.100 --cluster_domain=huangzai.com"

六、重启kubelet服务
[root@k8s_client1 ~]# systemctl restart kubelet

七、增加一个pod用于测试:
[root@k8s_master yaml]# vim busybox.yaml

apiVersion: v1
kind: Pod
metadata:
  labels:
    name: busybox
    role: master
  name: busybox
spec:
  containers:
  - name: busybox
    image: docker.io/busybox:latest
    command:
    - sleep
    - "3600"

[root@k8s_master yaml]# kubectl create -f busybox.yaml
pod "busybox" created

八、进入容器,容器内部执行域名解析命令。
[root@k8s_master yaml]# kubectl exec -it busybox sh
/ # nslookup kubernetes

Server:    10.254.0.100
Address 1: 10.254.0.100 kube-dns.kube-system.svc.huangzai.com

Name:      kubernetes
Address 1: 10.254.0.1 kubernetes.default.svc.huangzai.com

正常解析,kubedns部署成功

转载于:https://blog.51cto.com/jonauil/2087312

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