Question

我在kubernetes上使用DNS插件服务时收到错误。

如果我运行此命令，我看到正在重新启动kube-dns服务：

kubectl get pods --namespace=kube-system -o wide

当我获取日志时：

kubectl logs kube-dns-v9-7mi17 -c kube2sky --namespace=kube-system

我多次重复这个过程：

E0305 04:39:30.837572       1 reflector.go:136] Failed to list *api.Endpoints: Get https://10.3.0.1:443/api/v1/endpoints: dial tcp 10.3.0.1:443: i/o timeout
E0305 04:39:30.948322       1 reflector.go:136] Failed to list *api.Service: Get https://10.3.0.1:443/api/v1/services: dial tcp 10.3.0.1:443: i/o timeout
E0305 04:40:01.838219       1 reflector.go:136] Failed to list *api.Endpoints: Get https://10.3.0.1:443/api/v1/endpoints: dial tcp 10.3.0.1:443: i/o timeout
E0305 04:40:01.948954       1 reflector.go:136] Failed to list *api.Service: Get https://10.3.0.1:443/api/v1/services: dial tcp 10.3.0.1:443: i/o timeout

kubernetes服务已分配虚拟IP，但kubernetes的端点具有该服务的真实IP。 DNS服务是否应该尝试使用端点IP而不是虚拟IP来联系API服务器？

这是我用来创建DNS服务的定义：

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: 10.3.0.10
  ports:
  - name: dns
    port: 53
    protocol: UDP
  - name: dns-tcp
    port: 53
    protocol: TCP

这适用于DNS复制控制器：

apiVersion: v1
kind: ReplicationController
metadata:
  name: kube-dns-v9
  namespace: kube-system
  labels:
    k8s-app: kube-dns
    version: v9
    kubernetes.io/cluster-service: "true"
spec:
  replicas: 1
  selector:
    k8s-app: kube-dns
    version: v9
  template:
    metadata:
      labels:
        k8s-app: kube-dns
        version: v9
        kubernetes.io/cluster-service: "true"
    spec:
      containers:
      - name: etcd
        image: gcr.io/google_containers/etcd:2.0.9
        resources:
          limits:
            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:1.11
        resources:
          limits:
            cpu: 100m
            memory: 50Mi
        args:
        # command = "/kube2sky"
        - -domain=cluster.local
      - name: skydns
        image: gcr.io/google_containers/skydns:2015-03-11-001
        resources:
          limits:
            cpu: 100m
            memory: 50Mi
        args:
        # command = "/skydns"
        - -machines=http://localhost:4001
        - -addr=0.0.0.0:53
        - -domain=cluster.local.
        ports:
        - containerPort: 53
          name: dns
          protocol: UDP
        - containerPort: 53
          name: dns-tcp
          protocol: TCP
        livenessProbe:
          httpGet:
            path: /healthz
            port: 8080
            scheme: HTTP
          initialDelaySeconds: 30
          timeoutSeconds: 5
        readinessProbe:
          httpGet:
            path: /healthz
            port: 8080
            scheme: HTTP
          initialDelaySeconds: 1
          timeoutSeconds: 5
      - name: healthz
        image: gcr.io/google_containers/exechealthz:1.0
        resources:
          limits:
            cpu: 10m
            memory: 20Mi
        args:
        - -cmd=nslookup kubernetes.default.svc.cluster.local localhost >/dev/null
        - -port=8080
        ports:
        - containerPort: 8080
          protocol: TCP
      volumes:
      - name: etcd-storage
        emptyDir: {}
      dnsPolicy: Default

Answer 1

我在DNS上无法访问Kubernetes v1.6.1上的服务列表时遇到同样的问题。在github kubeadm issude thread here提到了这个问题。

我用前面提到的问题中的最新评论解决了这个问题：

2.其次，如果你的docker的版本＆gt; = 1.13，默认的FORWARD链策略是DROP，你应该将FORWARD链的默认策略设置为 ACCEPT：

sudo iptables -P FORWARD ACCEPT

Kubernetes DNS错误列出服务和端点

1 个答案: