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
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