我正在尝试使用分配给kube-dns服务的群集IP从dnstools容器中ping Kube-dns服务。 ping请求超时。在同一个dnstools窗格中,我尝试使用裸露的端口卷曲kube-dns服务,但也超时。
以下是kubectl get pods --all-namespaces -o wide
NAMESPACE NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE
default pod/busybox 1/1 Running 62 2d14h 192.168.1.37 kubenode <none>
default pod/dnstools 1/1 Running 0 2d13h 192.168.1.45 kubenode <none>
default pod/nginx-deploy-7c45b84548-ckqzb 1/1 Running 0 6d11h 192.168.1.5 kubenode <none>
default pod/nginx-deploy-7c45b84548-vl4kh 1/1 Running 0 6d11h 192.168.1.4 kubenode <none>
dmi pod/elastic-deploy-5d7c85b8c-btptq 1/1 Running 0 2d14h 192.168.1.39 kubenode <none>
kube-system pod/calico-node-68lc7 2/2 Running 0 6d11h 10.62.194.5 kubenode <none>
kube-system pod/calico-node-9c2jz 2/2 Running 0 6d12h 10.62.194.4 kubemaster <none>
kube-system pod/coredns-5c98db65d4-5nprd 1/1 Running 0 6d12h 192.168.0.2 kubemaster <none>
kube-system pod/coredns-5c98db65d4-5vw95 1/1 Running 0 6d12h 192.168.0.3 kubemaster <none>
kube-system pod/etcd-kubemaster 1/1 Running 0 6d12h 10.62.194.4 kubemaster <none>
kube-system pod/kube-apiserver-kubemaster 1/1 Running 0 6d12h 10.62.194.4 kubemaster <none>
kube-system pod/kube-controller-manager-kubemaster 1/1 Running 1 6d12h 10.62.194.4 kubemaster <none>
kube-system pod/kube-proxy-9hcgv 1/1 Running 0 6d11h 10.62.194.5 kubenode <none>
kube-system pod/kube-proxy-bxw9s 1/1 Running 0 6d12h 10.62.194.4 kubemaster <none>
kube-system pod/kube-scheduler-kubemaster 1/1 Running 1 6d12h 10.62.194.4 kubemaster <none>
kube-system pod/tiller-deploy-767d9b9584-5k95j 1/1 Running 0 3d9h 192.168.1.8 kubenode <none>
nginx-ingress pod/nginx-ingress-66wts 1/1 Running 0 5d17h 192.168.1.6 kubenode <none>
在上面的输出中,为什么有些Pod在192.168.0.0/24
子网中分配了IP,而另一些Pod却等于我的节点/主服务器的IP地址? (10.62.194.4是我的主服务器的IP,10.62.194.5是我的节点的IP)
这是config.yml
,我曾经使用kubeadm init --config=config.yml
初始化集群
apiServer:
certSANs:
- 10.62.194.4
extraArgs:
authorization-mode: Node,RBAC
timeoutForControlPlane: 4m0s
apiVersion: kubeadm.k8s.io/v1beta2
certificatesDir: /etc/kubernetes/pki
clusterName: dev-cluster
controllerManager: {}
dns:
type: CoreDNS
etcd:
local:
dataDir: /var/lib/etcd
imageRepository: k8s.gcr.io
kind: ClusterConfiguration
kubernetesVersion: v1.15.1
networking:
dnsDomain: cluster.local
podSubnet: 192.168.0.0/16
serviceSubnet: 10.96.0.0/12
scheduler: {}
kubectl get svc --all-namespaces -o wide
的结果
NAMESPACE NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
default service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 6d12h <none>
default service/nginx-deploy ClusterIP 10.97.5.194 <none> 80/TCP 5d17h run=nginx
dmi service/elasticsearch ClusterIP 10.107.84.159 <none> 9200/TCP,9300/TCP 2d14h app=dmi,component=elasticse
dmi service/metric-server ClusterIP 10.106.117.2 <none> 8098/TCP 2d14h app=dmi,component=metric-se
kube-system service/calico-typha ClusterIP 10.97.201.232 <none> 5473/TCP 6d12h k8s-app=calico-typha
kube-system service/kube-dns ClusterIP 10.96.0.10 <none> 53/UDP,53/TCP,9153/TCP 6d12h k8s-app=kube-dns
kube-system service/tiller-deploy ClusterIP 10.98.133.94 <none> 44134/TCP 3d9h app=helm,name=tiller
我运行的命令是kubectl exec -ti dnstools -- curl 10.96.0.10:53
答案 0 :(得分:1)
答案 1 :(得分:0)
kubernetes系统Pod被分配了主机ip,因为它们提供了不依赖于覆盖网络的底层服务(或者在calico情况下甚至提供了覆盖网络)。它们具有运行节点的ip。
一个普通的Pod使用覆盖网络,并从calico范围(而不是从它们运行的金属节点)分配IP。
您不能使用curl使用HTTP访问DNS(端口53)。您可以使用dig
来查询DNS解析器。
通过ping无法访问服务IP,因为它是一个虚拟IP,仅用作kube-proxy设置的iptables规则的路由句柄,因此TCP连接有效,但ICMP无效。
不过,您可以ping Pod IP,因为它是从覆盖网络分配的。
答案 2 :(得分:0)
在某些情况下,Elasticsearch发布的本地主机无法通过其他主机路由/访问。在这些情况下,您将必须在yml配置文件中配置Rate
,以便Elasticsearch使用和发布正确的地址。
尝试将network.publish_host配置为正确的公共地址。
答案 3 :(得分:0)
请注意,在主节点上运行的诸如api服务器,etcd之类的控制平面组件已绑定到主机网络。因此,您会看到主服务器的IP地址。
另一方面,您部署的应用程序将从pod子网范围中获取ip。这些与群集节点ip的不同
尝试以下步骤测试dns是否正常工作
部署nginx.yaml
apiVersion: v1
kind: Service
metadata:
name: nginx
labels:
app: nginx
spec:
ports:
- port: 80
name: web
clusterIP: None
selector:
app: nginx
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
name: web
labels:
app: nginx
spec:
serviceName: "nginx"
replicas: 2
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: k8s.gcr.io/nginx-slim:0.8
ports:
- containerPort: 80
name: web
volumeMounts:
- name: www
mountPath: /usr/share/nginx/html
volumes:
- name: www
emptyDir:
kuebctl create -f nginx.yaml
master $ kubectl get po
NAME READY STATUS RESTARTS AGE
web-0 1/1 Running 0 1m
web-1 1/1 Running 0 1m
master $ kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 35m
nginx ClusterIP None <none> 80/TCP 2m
master $ kubectl run -i --tty --image busybox:1.28 dns-test --restart=Never --rm
If you don't see a command prompt, try pressing enter.
/ # nslookup nginx
Server: 10.96.0.10
Address 1: 10.96.0.10 kube-dns.kube-system.svc.cluster.local
Name: nginx
Address 1: 10.40.0.1 web-0.nginx.default.svc.cluster.local
Address 2: 10.40.0.2 web-1.nginx.default.svc.cluster.local
/ #
/ # nslookup web-0.nginx
Server: 10.96.0.10
Address 1: 10.96.0.10 kube-dns.kube-system.svc.cluster.local
Name: web-0.nginx
Address 1: 10.40.0.1 web-0.nginx.default.svc.cluster.local
/ # nslookup web-0.nginx.default.svc.cluster.local
Server: 10.96.0.10
Address 1: 10.96.0.10 kube-dns.kube-system.svc.cluster.local
Name: web-0.nginx.default.svc.cluster.local
Address 1: 10.40.0.1 web-0.nginx.default.svc.cluster.local