Kubernetes-dns

kubernetes中的dns主要用于服务发现，当创建service后可以通过service名称进行通信，例如：

下图的service创建后，其他pod就可以通过域名c.codeus解析出这个service下pod的ip

搭建dns需要下面三个镜像

docker pull registry.cn-hangzhou.aliyuncs.com/inspur_research/k8s-dns-sidecar-amd64:1.14.5

docker pull registry.cn-hangzhou.aliyuncs.com/wonders/k8s-dns-kube-dns-amd64:1.14.5

docker pull registry.cn-hangzhou.aliyuncs.com/inspur_research/k8s-dns-dnsmasq-nanny-amd64:1.14.5

创建kubedns-controller.yaml

# cat 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

imagePullSecrets:

- name: registry-key

containers:

- name: kubedns

image: registry.cn-hangzhou.aliyuncs.com/wonders/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

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: registry.cn-hangzhou.aliyuncs.com/inspur_research/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

- --no-negcache

- --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: registry.cn-hangzhou.aliyuncs.com/inspur_research/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

创建kubedns-svc.yaml

下面的 clusterIP: 10.0.0.2配置为自定义配置，跟集群ip处于同一个网段，通过以下命令查看集群ip后自定义

# kubectl get svc

NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE

kubernetes ClusterIP 10.0.0.1 <none> 443/TCP 34d

# cat 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: 10.0.0.2

ports:

- name: dns

port: 53

protocol: UDP

- name: dns-tcp

port: 53

protocol: TCP

创建kubedns-cm.yaml

# cat kubedns-cm.yaml

apiVersion: v1

kind: ConfigMap

metadata:

name: kube-dns

namespace: kube-system

labels:

addonmanager.kubernetes.io/mode: EnsureExists

创建kubedns-sa.yaml

# cat 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

启动

kubectl create -f kubedns-controller.yaml --validate=false

kubectl create -f kubedns-cm.yaml

kubectl create -f kubedns-sa.yaml

kubectl create -f kubedns-svc.yaml

成功后重启已经启动的容器，容器中的dns配置会自动指向dns-pod的ip

dns-pod中的dns指向是所在宿主机的dns配置

可通过查看容器中的cat /etc/resolv.conf查看

原文地址：https://blog.csdn.net/wangjunsheng/article/details/86095544

kubectl create -f kubedns-controller.yaml --validate=false

kubectl create -f kubedns-cm.yaml

kubectl create -f kubedns-sa.yaml

kubectl create -f kubedns-svc.yaml

---------------------

作者：乃不知有汉

来源：CSDN

原文：https://blog.csdn.net/wangjunsheng/article/details/86095544