K8S在开发测试环境落地问题处理之内网DNS解析

思路:
1.获取K8S容器云中所有namespace下的所有Service，然后制定规则如所有的web服务以完整的域名作为服务名，比如我们的api.abc.com那么服务名就是api-abc-com，然后把kube-system过滤掉
2.根据上述获取到的namespace、域名、ClusterIP写入到对应文件夹下的DNS配置文件,如果存在则删除再增加，如果不存在则自动添加
3.将各个命名空间的DNS配置文件进行加载

#!/bin/bash
svc=$(kubectl get svc --all-namespaces|awk ‘/-/ && NR!=1 && !/kube-system/ {print $1,$2,$4}‘|sed ‘s#-#.#g‘)
echo "$svc"|while read line
do
        namespace=`echo $line|awk ‘{print $1}‘`
        [ -d $namespace ] || mkdir -p ${namespace}
        [ -f ${namespace}/dns ] || touch ${namespace}/dns
        domain=`echo $line|awk ‘{print $2}‘`
        dns_record=`echo $line|awk ‘{print $2"="$3}‘`
        [ `grep ${dns_record} ${namespace}/dns|wc -l` ] && sed -i "/${domain}/d" ${namespace}/dns && echo ${dns_record}>>${namespace}/dns
        names=`cat ${namespace}/dns | grep -v ‘^#|^//‘ | tr ‘\n‘ ‘,‘|sed ‘s/,$//g‘`
        sed "s#{namespace}#${namespace}#g" ~/yaml/dns/deploy.yaml | sed "s#{names}#${names}#g"|kubectl apply -f -
done

查看DNS的deploy-svc.yaml

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: dns
  namespace: {namespace}
spec:
  selector:
    matchLabels:
      name: dns
  replicas: 1
  template:
    metadata:
      labels:
        name: dns
    spec:
      containers:
      - name: bind
        image: cytopia/bind
        ports:
        - containerPort: 53
          protocol: TCP
          name: dnstcp
        - containerPort: 53
          protocol: UDP
          name: dnsudp
        env:
        - name: EXTRA_HOSTS
          value: "{names}"
        - name: DNS_FORWARDER
          value: "114.114.114.144,8.8.4.4"   #此处为外网的DNS服务器
---

apiVersion: v1
kind: Service
metadata:
  name: dns
  namespace: {namespace}
  labels:
    name: dns
spec:
  ports:
  - protocol: TCP
    port: 53
    targetPort: 53
    name: dnstcp
  - protocol: UDP
    port: 53
    targetPort: 53
    name: dnsudp
  selector:
    name: dns

K8S在开发测试环境落地问题处理之内网DNS解析

原文：http://blog.51cto.com/fengwan/2309976