基础环境
基本的k8s集群，安装部署可参考我的文章。
部署kubedns步骤
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准备镜像
# kingdragon 是我的docker hub仓库，你可以换成自己的仓库，并准备相应的镜像 kingdragon/k8s-dns-dnsmasq-nanny-amd64:1.14.5 kingdragon/k8s-dns-kube-dns-amd64:1.14.5 kingdragon/k8s-dns-sidecar-amd64:1.14.5 -
准备yaml文件
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kubedns-cm.yaml
apiVersion: v1 kind: ConfigMap metadata: name: kube-dns namespace: kube-system labels: addonmanager.kubernetes.io/mode: EnsureExists -
kubedns-controller.yaml
apiVersion: extensions/v1beta1 kind: Deployment metadata: name: kube-dns namespace: kube-system labels: k8s-app: kube-dns kubernetes.io/cluster-service: "true" addonmanager.kubernetes.io/mode: Reconcile 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: 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: '' spec: tolerations: - key: "CriticalAddonsOnly" operator: "Exists" volumes: - name: kube-dns-config configMap: name: kube-dns optional: true containers: - name: kubedns image: kingdragon/k8s-dns-kube-dns-amd64:1.14.5 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: /healthcheck/kubedns port: 10054 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: - --domain=cluster.local. - --dns-port=10053 - --config-dir=/kube-dns-config - --v=2 #__PILLAR__FEDERATIONS__DOMAIN__MAP__ 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 volumeMounts: - name: kube-dns-config mountPath: /kube-dns-config - name: dnsmasq image: kingdragon/k8s-dns-dnsmasq-nanny-amd64:1.14.5 livenessProbe: httpGet: path: /healthcheck/dnsmasq port: 10054 scheme: HTTP initialDelaySeconds: 60 timeoutSeconds: 5 successThreshold: 1 failureThreshold: 5 args: - -v=2 - -logtostderr - -configDir=/etc/k8s/dns/dnsmasq-nanny - -restartDnsmasq=true - -- - -k - --cache-size=1000 - --log-facility=- - --server=/cluster.local./127.0.0.1#10053 - --server=/in-addr.arpa/127.0.0.1#10053 - --server=/ip6.arpa/127.0.0.1#10053 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: 20Mi volumeMounts: - name: kube-dns-config mountPath: /etc/k8s/dns/dnsmasq-nanny - name: sidecar image: kingdragon/k8s-dns-sidecar-amd64:1.14.5 livenessProbe: httpGet: path: /metrics port: 10054 scheme: HTTP initialDelaySeconds: 60 timeoutSeconds: 5 successThreshold: 1 failureThreshold: 5 args: - --v=2 - --logtostderr - --probe=kubedns,127.0.0.1:10053,kubernetes.default.svc.cluster.local.,5,A - --probe=dnsmasq,127.0.0.1:53,kubernetes.default.svc.cluster.local.,5,A ports: - containerPort: 10054 name: metrics protocol: TCP resources: requests: memory: 20Mi cpu: 10m dnsPolicy: Default # Don't use cluster DNS. serviceAccountName: kube-dns补充：
1、改镜像地址为你自己的镜像仓库。
2、cluster.local.为集群的域名，参见你配置集群时的cluster.domin参数的值。 -
kubedns-sa.yaml
apiVersion: v1 kind: ServiceAccount metadata: name: kube-dns namespace: kube-system labels: kubernetes.io/cluster-service: "true" addonmanager.kubernetes.io/mode: Reconcile -
kubedns-svc.yaml
apiVersion: v1 kind: Service metadata: name: kube-dns namespace: kube-system labels: k8s-app: kube-dns kubernetes.io/cluster-service: "true" addonmanager.kubernetes.io/mode: Reconcile kubernetes.io/name: "KubeDNS" spec: selector: k8s-app: kube-dns clusterIP: 10.254.0.2 ports: - name: dns port: 53 protocol: UDP - name: dns-tcp port: 53 protocol: TCP补充：
clusterIP: 10.254.0.2 即明确指定了 kube-dns Service IP，这个 IP 需要和 kubelet 的 --cluster-dns 参数值一致。
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部署kubedns
# 路径可以不一样 $ pwd /root/kubedns $ ls *.yaml kubedns-cm.yaml kubedns-controller.yaml kubedns-sa.yaml kubedns-svc.yaml $ kubectl create -f . -
校验
$ cat >> my-nginx.yaml << EOF apiVersion: extensions/v1beta1 kind: Deployment metadata: name: my-nginx spec: replicas: 2 template: metadata: labels: run: my-nginx spec: containers: - name: my-nginx image: harbor-001.jimmysong.io/library/nginx:1.9 ports: - containerPort: 80 EOF $ kubectl create -f my-nginx.yaml # Export 该 Deployment, 生成 my-nginx 服务 $ kubectl expose deploy my-nginx $ kubectl get services --all-namespaces |grep my-nginx # 创建另一个 Pod，查看 `/etc/resolv.conf` 是否包含 `kubelet` 配置的 `--cluster-dns` 和 `--cluster-domain`，是否能够将服务 `my-nginx` 解析到 Cluster IP `10.254.179.239`。 $ kubectl create -f nginx-pod.yaml $ kubectl exec nginx -i -t -- /bin/bash root@nginx:/# cat /etc/resolv.conf nameserver 10.254.0.2 search default.svc.cluster.local. svc.cluster.local. cluster.local. jimmysong.io options ndots:5 root@nginx:/# ping my-nginx PING my-nginx.default.svc.cluster.local (10.254.179.239): 56 data bytes 76 bytes from 119.147.223.109: Destination Net Unreachable ^C--- my-nginx.default.svc.cluster.local ping statistics --- root@nginx:/# ping kubernetes PING kubernetes.default.svc.cluster.local (10.254.0.1): 56 data bytes ^C--- kubernetes.default.svc.cluster.local ping statistics --- 11 packets transmitted, 0 packets received, 100% packet loss root@nginx:/# ping kube-dns.kube-system.svc.cluster.local PING kube-dns.kube-system.svc.cluster.local (10.254.0.2): 56 data bytes ^C--- kube-dns.kube-system.svc.cluster.local ping statistics --- 6 packets transmitted, 0 packets received, 100% packet loss