Kubernetes DNS在Kubernetes 1.2中失败

我正在尝试在Centos 7上的Kubernetes 1.2中设置DNS支持。根据调查，有两种方法可以做到这一点。第一种适用于“受支持的kubernetes群集设置”，包括设置环境变量：

ENABLE_CLUSTER_DNS="${KUBE_ENABLE_CLUSTER_DNS:-true}"
DNS_SERVER_IP="10.0.0.10"
DNS_DOMAIN="cluster.local"
DNS_REPLICAS=1

我将这些设置添加到/etc/kubernetes/config并重新启动，但没有任何效果，因此要么我没有受支持的kubernetes集群设置（这是什么？），要么需要其他东西来设置其环境

第二种方法需要更多的手动设置。它向kubelets添加了两个标志，我通过更新/etc/kubernetes/kubelets将其设置为包括：

KUBELET_ARGS="--cluster-dns=10.0.0.10 --cluster-domain=cluster.local"

并使用

systemctl restart kubelet

重新启动kubelet。然后需要启动一个复制控制器和一个服务。上面引用的doc页面为此提供了两个模板文件，需要进行一些编辑，既可以用于本地更改（我的Kubernetes API服务器侦听主机名的实际IP地址，而不是127.0.0.1，因此需要添加--kube主url设置），也可以删除一些Salt依赖项。执行此操作时，replication controller成功启动了四个容器，但kube2sky容器在完成初始化大约一分钟后终止：

[david@centos dns]$ kubectl --server="http://centos:8080" --namespace="kube-system" logs -f kube-dns-v11-t7nlb -c kube2sky
I0325 20:58:18.516905       1 kube2sky.go:462] Etcd server found: http://127.0.0.1:4001
I0325 20:58:19.518337       1 kube2sky.go:529] Using http://192.168.87.159:8080 for kubernetes master
I0325 20:58:19.518364       1 kube2sky.go:530] Using kubernetes API v1
I0325 20:58:19.518468       1 kube2sky.go:598] Waiting for service: default/kubernetes
I0325 20:58:19.533597       1 kube2sky.go:660] Successfully added DNS record for Kubernetes service.
F0325 20:59:25.698507       1 kube2sky.go:625] Received signal terminated

我已确定终止由healthz容器在报告后完成：

2016/03/25 21:00:35 Client ip 172.17.42.1:58939 requesting /healthz probe servicing cmd nslookup kubernetes.default.svc.cluster.local 127.0.0.1 >/dev/null
2016/03/25 21:00:35 Healthz probe error: Result of last exec: nslookup: can't resolve 'kubernetes.default.svc.cluster.local', at 2016-03-25 21:00:35.608106622 +0000 UTC, error exit status 1

除此之外，所有其他日志看起来都很正常。但是，有一个异常情况：在创建复制控制器时必须指定--validate=false，否则该命令会收到以下消息：

error validating "skydns-rc.yaml": error validating data: [found invalid field successThreshold for v1.Probe, found invalid field failureThreshold for v1.Probe]; if you choose to ignore these errors, turn validation off with --validate=false

这有关系吗？这些参数直接来自Kubernetes文档。如果没有，需要什么来运行它

以下是我使用的skydns-rc.yaml：

apiVersion: v1
kind: ReplicationController
metadata:
  name: kube-dns-v11
  namespace: kube-system
  labels:
    k8s-app: kube-dns
    version: v11
    kubernetes.io/cluster-service: "true"
spec:
  replicas: 1
  selector:
    k8s-app: kube-dns
    version: v11
  template:
    metadata:
      labels:
        k8s-app: kube-dns
        version: v11
        kubernetes.io/cluster-service: "true"
    spec:
      containers:
      - name: etcd
        image: gcr.io/google_containers/etcd-amd64:2.2.1
        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:
            cpu: 100m
            memory: 500Mi
          requests:
            cpu: 100m
            memory: 50Mi
        command:
        - /usr/local/bin/etcd
        - -data-dir
        - /var/etcd/data
        - -listen-client-urls
        - http://127.0.0.1:2379,http://127.0.0.1:4001
        - -advertise-client-urls
        - http://127.0.0.1:2379,http://127.0.0.1:4001
        - -initial-cluster-token
        - skydns-etcd
        volumeMounts:
        - name: etcd-storage
          mountPath: /var/etcd/data
      - name: kube2sky
        image: gcr.io/google_containers/kube2sky:1.14
        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:
            cpu: 100m
            # Kube2sky watches all pods.
            memory: 200Mi
          requests:
            cpu: 100m
            memory: 50Mi
        livenessProbe:
          httpGet:
            path: /healthz
            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: 30
          timeoutSeconds: 5
        args:
        # command = "/kube2sky"
        - --domain="cluster.local"
        - --kube-master-url=http://192.168.87.159:8080
      - name: skydns
        image: gcr.io/google_containers/skydns:2015-10-13-8c72f8c
        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:
            cpu: 100m
            memory: 200Mi
          requests:
            cpu: 100m
            memory: 50Mi
        args:
        # command = "/skydns"
        - -machines=http://127.0.0.1:4001
        - -addr=0.0.0.0:53
        - -ns-rotate=false
        - -domain="cluster.local"
        ports:
        - containerPort: 53
          name: dns
          protocol: UDP
        - containerPort: 53
          name: dns-tcp
          protocol: TCP
      - name: healthz
        image: gcr.io/google_containers/exechealthz:1.0
        resources:
          # keep request = limit to keep this container in guaranteed class
          limits:
            cpu: 10m
            memory: 20Mi
          requests:
            cpu: 10m
            memory: 20Mi
        args:
        - -cmd=nslookup kubernetes.default.svc.cluster.local 127.0.0.1 >/dev/null
        - -port=8080
        ports:
        - containerPort: 8080
          protocol: TCP
      volumes:
      - name: etcd-storage
        emptyDir: {}
      dnsPolicy: Default  # Don't use cluster DNS.

和skydns-svc.yaml：

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:  "10.0.0.10"
  ports:
  - name: dns
    port: 53
    protocol: UDP
  - name: dns-tcp
    port: 53
    protocol: TCP

---

我刚刚注释掉了

skydns rc.yaml

中包含

successThreshold

和

failureurreshold

值的行，然后重新运行kubectl命令

kubectl create -f skydns-rc.yaml
kubectl create -f skydns-svc.yaml

---

谢谢你的建议。不幸的是，这没有什么区别。服务集群IP范围的价值是什么？确保您的DNS IP与您在其中指定的值位于同一网络中。这就是问题所在！谢谢，我也有同样的问题。我在哪里可以找到服务群集IP范围？如果我在本地ubuntu机器上运行，我应该将其设置为什么？查看

cluster/ubuntu/config default.sh

。如果您的Ubuntu机器有一个典型的192.168.1.0/24网络，请将

服务\u集群\u IP\u范围的值设置为192.168.254.0/24或类似的不与主网络重叠的值。然后选择
DNS\u SERVER\u IP
的值在该范围内，192.168.254.10。