k8s基于etcd的CoreDNS动态域名解析

土小帽

下载coredns yaml部署脚本
注意：如果已经部署coredns可忽略

1. wget https://github.com/coredns/deployment/raw/master/kubernetes/coredns.yaml.sed
   
2. wget https://github.com/coredns/deployment/raw/master/kubernetes/deploy.sh
   
3. chmod +x deploy.sh

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重新打coredns镜像
想将dns记录存在etcd中，如果内部https，etcd必须打证书，应此coredns必须带证书，将k8s相关证书打入coredns

1. mkdir /root/coredns
   
2. docker pull coredns/coredns:1.3.1
   
3. cp /etc/kubernetes/ssl/kubernetes .
   
4. cp /etc/kubernetes/ssl/k8s-root-ca.pem .

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Dockerfile

1. FROM coredns/coredns:1.3.1
   
2. ADD ./*.pem /

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Makefile

1. VERSION=1.3.1-etcd
   
2. REGISTRY=hub.linuxeye.com
   
3. NAME=coredns
   
4. build-image:
   
5.         docker build -f Dockerfile -t $(REGISTRY)/library/$(NAME):$(VERSION) .
   
6.         docker push $(REGISTRY)/library/$(NAME):$(VERSION)

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build、推送镜像

1. make build-image

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替换image地址
vi coredns.yaml.sed

修改image镜像：hub.linuxeye.com/library/coredns:1.3.1-etcd

如果之前已经部署了coredns，修改coredns yaml镜像地址

kube-dns替换为coredns
注意：如果已经部署coredns可忽略

在k8s master节点执行，其中：172.22.0.2为 dns server ip

1. ./deploy.sh -i 172.22.0.2 | kubectl apply -f -

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etcd存入hosts记录
注意：如果coredns是1.2.0以前版本，使用的是etcdv2 API版本，1.2.0及之后版本，使用etcdv3 API版本etcd V2:

1. #设置key
   
2. etcdctl --ca-file=/etc/kubernetes/ssl/k8s-root-ca.pem --cert-file=/etc/kubernetes/ssl/kubernetes.pem --key-file=/etc/kubernetes/ssl/kubernetes-key.pem set /mydomain/kafka11 '{"Host":"10.50.1.11"}'
   
3. etcdctl --ca-file=/etc/kubernetes/ssl/k8s-root-ca.pem --cert-file=/etc/kubernetes/ssl/kubernetes.pem --key-file=/etc/kubernetes/ssl/kubernetes-key.pem set /mydomain/kafka12 '{"Host":"10.50.1.12"}'
   
4. etcdctl --ca-file=/etc/kubernetes/ssl/k8s-root-ca.pem --cert-file=/etc/kubernetes/ssl/kubernetes.pem --key-file=/etc/kubernetes/ssl/kubernetes-key.pem set /mydomain/kafka13 '{"Host":"10.50.1.13"}'
   
5. #验证获取key
   
6. etcdctl --ca-file=/etc/kubernetes/ssl/k8s-root-ca.pem --cert-file=/etc/kubernetes/ssl/kubernetes.pem --key-file=/etc/kubernetes/ssl/kubernetes-key.pem set /mydomain/kafka11
   
7. etcdctl --ca-file=/etc/kubernetes/ssl/k8s-root-ca.pem --cert-file=/etc/kubernetes/ssl/kubernetes.pem --key-file=/etc/kubernetes/ssl/kubernetes-key.pem set /mydomain/kafka12
   
8. etcdctl --ca-file=/etc/kubernetes/ssl/k8s-root-ca.pem --cert-file=/etc/kubernetes/ssl/kubernetes.pem --key-file=/etc/kubernetes/ssl/kubernetes-key.pem set /mydomain/kafka13

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etcd V3

1. #设置key
   
2. ETCDCTL_API=3 etcdctl --ca-file=/etc/kubernetes/ssl/k8s-root-ca.pem --cert-file=/etc/kubernetes/ssl/kubernetes.pem --key-file=/etc/kubernetes/ssl/kubernetes-key.pem put /mydomain/kafka11 '{"Host":"10.50.1.11"}'
   
3. ETCDCTL_API=3 etcdctl --ca-file=/etc/kubernetes/ssl/k8s-root-ca.pem --cert-file=/etc/kubernetes/ssl/kubernetes.pem --key-file=/etc/kubernetes/ssl/kubernetes-key.pem put /mydomain/kafka12 '{"Host":"10.50.1.12"}'
   
4. ETCDCTL_API=3 etcdctl --ca-file=/etc/kubernetes/ssl/k8s-root-ca.pem --cert-file=/etc/kubernetes/ssl/kubernetes.pem --key-file=/etc/kubernetes/ssl/kubernetes-key.pem put /mydomain/kafka13 '{"Host":"10.50.1.13"}'
   
5. #验证获取key
   
6. ETCDCTL_API=3 etcdctl --ca-file=/etc/kubernetes/ssl/k8s-root-ca.pem --cert-file=/etc/kubernetes/ssl/kubernetes.pem --key-file=/etc/kubernetes/ssl/kubernetes-key.pem set /mydomain/kafka11
   
7. ETCDCTL_API=3 etcdctl --ca-file=/etc/kubernetes/ssl/k8s-root-ca.pem --cert-file=/etc/kubernetes/ssl/kubernetes.pem --key-file=/etc/kubernetes/ssl/kubernetes-key.pem set /mydomain/kafka12
   
8. ETCDCTL_API=3 etcdctl --ca-file=/etc/kubernetes/ssl/k8s-root-ca.pem --cert-file=/etc/kubernetes/ssl/kubernetes.pem --key-file=/etc/kubernetes/ssl/kubernetes-key.pem set /mydomain/kafka13

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修改配置字典
命名空间kube-system coredns：

1. .:53 {
   
2.     errors
   
3.     health
   
4.     kubernetes cluster.local in-addr.arpa ip6.arpa {
   
5.       pods insecure
   
6.       upstream
   
7.       fallthrough in-addr.arpa ip6.arpa
   
8.     }
   
9.     prometheus :9153
   
10.     cache 30
    
11.     reload
    
12.     proxy . /etc/resolv.conf {
    
13.       except kafka11 kafka12 kafka13
    
14.     }
    
15.     etcd kafka11 kafka12 kafka13 {
    
16.       stubzones
    
17.       path /mydomain
    
18.       endpoint https://10.1.1.6:2379 https://10.1.1.7:2379 https://10.1.1.8:2379
    
19.       tls /kubernetes.pem /kubernetes-key.pem /k8s-root-ca.pem
    
20.     }
    
21. }
    

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