1.6 DNS 服务
目前常用的 dns 组件有 kube-dns 和 coredns 两个，用于解析 k8s 集群中 service name 所对应得到 IP 地址。
早期版本有 skyDNS（已经废弃），后来被 kube-dns 取代，在1.18.0版本以后已经废弃，现在使用 coredns。
在kubeasz项目中准备目录
[root@k8s-master1 ~]# cd /etc/kubeasz/
[root@k8s-master1 /etc/kubeasz]# mkdir manifests/dns/{kube-dns,coredns} -pv
mkdir: created directory 'manifests/dns'
mkdir: created directory 'manifests/dns/kube-dns'
mkdir: created directory 'manifests/dns/coredns'
[root@k8s-master1 /etc/kubeasz]# 1.6.1 部署 coredns
github 项目地址：
https://github.com/coredns/coredns # 项目地址
https://github.com/coredns/deployment # 克隆项目
https://github.com/coredns/deployment/tree/master/kubernetes # 部署教程部署 coredns
# 准备文件
[root@k8s-master1 /etc/kubeasz]# cd manifests/dns/coredns/
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]# ll
total 3912
drwxr-xr-x 2 root root 4096 Nov 14 15:04 ./
drwxr-xr-x 4 root root 4096 Nov 14 15:04 ../
-rw-r--r-- 1 root root 3983872 Feb 26 2021 busybox-online.tar.gz
-rw-r--r-- 1 root root 286 Nov 9 22:47 busybox.yaml
-rw-r--r-- 1 root root 4542 Nov 9 20:52 waluna-coredns.yml
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]#
# 查看镜像
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]# grep image waluna-coredns.yml
#image: coredns/coredns:1.8.6
image: harbor.waluna.top/baseimages/coredns:v1.8.6
imagePullPolicy: IfNotPresent
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]#
# 拉取镜像并打标签上传至本地harbor
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]# docker pull coredns/coredns:1.8.6
1.8.6: Pulling from coredns/coredns
d92bdee79785: Pull complete
6e1b7c06e42d: Pull complete
Digest: sha256:5b6ec0d6de9baaf3e92d0f66cd96a25b9edbce8716f5f15dcd1a616b3abd590e
Status: Downloaded newer image for coredns/coredns:1.8.6
docker.io/coredns/coredns:1.8.6
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]# docker tag coredns/coredns:1.8.6 harbor.waluna.top/baseimages/coredns:v1.8.6
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]# docker push harbor.waluna.top/baseimages/coredns:v1.8.6
The push refers to repository [harbor.waluna.top/baseimages/coredns]
80e4a2390030: Pushed
256bc5c338a6: Pushed
v1.8.6: digest: sha256:8916c89e1538ea3941b58847e448a2c6d940c01b8e716b20423d2d8b189d3972 size: 739
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]#
# 修改镜像地址
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]# vim waluna.coredns.yml
......
containers:
- name: coredns
#image: coredns/coredns:1.8.6
image: harbor.waluna.top/baseimages/coredns:v1.8.6
......
# 安装coredns
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]# kubectl apply -f waluna-coredns.yml
serviceaccount/coredns created
clusterrole.rbac.authorization.k8s.io/system:coredns created
clusterrolebinding.rbac.authorization.k8s.io/system:coredns created
configmap/coredns created
deployment.apps/coredns created
service/kube-dns created
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]#
# 查看pod
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]# kubectl get pod -A|grep coredns
kube-system coredns-597578ff46-x2s95 1/1 Running 0 10s
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]#
# 验证dns
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]# kubectl exec net-test1 -- ping baidu.com -c1
PING baidu.com (220.181.38.148): 56 data bytes
64 bytes from 220.181.38.148: seq=0 ttl=127 time=18.889 ms
--- baidu.com ping statistics ---
1 packets transmitted, 1 packets received, 0% packet loss
round-trip min/avg/max = 18.889/18.889/18.889 ms
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]# 1.6.2 域名解析测试
下面使用 busybox 进行测试
# 准备busybox镜像
[root@k8s-master1 ~]# cd /etc/kubeasz/manifests/dns/coredns
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]# ll busybox-online.tar.gz
-rw-r--r-- 1 root root 3983872 Feb 26 2021 busybox-online.tar.gz
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]# docker load -i busybox-online.tar.gz
6a749002dd6a: Loading layer [==================================================>] 1.338MB/1.338MB
5f70bf18a086: Loading layer [==================================================>] 1.024kB/1.024kB
1692ded805c8: Loading layer [==================================================>] 2.629MB/2.629MB
Loaded image: quay.io/prometheus/busybox:latest
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]# docker tag quay.io/prometheus/busybox:latest harbor.waluna.top/baseimages/busybox:latest
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]# docker push harbor.waluna.top/baseimages/busybox:latest
The push refers to repository [harbor.waluna.top/baseimages/busybox]
1692ded805c8: Pushed
5f70bf18a086: Pushed
6a749002dd6a: Pushed
latest: digest: sha256:51ffe0b73b49d0e7045f7037fb9f8360604121533d90881c08ad3a21a5e18843 size: 943
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]#
# 创建pod
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]# kubectl apply -f busybox.yaml
pod/busybox createdpod/busybox created
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]#
# 域名测试
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]# kubectl get svc -A
NAMESPACE NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
default kubernetes ClusterIP 10.20.0.1 <none> 443/TCP 19m
kube-system kube-dns ClusterIP 10.20.0.2 <none> 53/UDP,53/TCP,9153/TCP 7m53s
kubernetes-dashboard dashboard-metrics-scraper ClusterIP 10.20.164.123 <none> 8000/TCP 11m
kubernetes-dashboard kubernetes-dashboard NodePort 10.20.242.83 <none> 443:30002/TCP 11m
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]# kubectl get pod -A
NAMESPACE NAME READY STATUS RESTARTS AGE
default busybox 1/1 Running 0 66s
default net-test1 1/1 Running 1 15m
default net-test2 1/1 Running 1 15m
default net-test3 1/1 Running 1 15m
default net-test4 1/1 Running 1 15m
default net-test5 1/1 Running 1 15m
default net-test6 1/1 Running 1 15m
kube-system coredns-597578ff46-x2s95 1/1 Running 1 8m41s
kube-system kube-flannel-ds-amd64-2np97 1/1 Running 1 17m
kube-system kube-flannel-ds-amd64-45brr 1/1 Running 1 17m
kube-system kube-flannel-ds-amd64-7gglf 1/1 Running 1 17m
kube-system kube-flannel-ds-amd64-j2wf9 1/1 Running 1 17m
kube-system kube-flannel-ds-amd64-k4bcl 1/1 Running 1 17m
kube-system kube-flannel-ds-amd64-s8rkq 1/1 Running 1 17m
kubernetes-dashboard dashboard-metrics-scraper-5b8df6cd57-jmznl 1/1 Running 1 12m
kubernetes-dashboard kubernetes-dashboard-56dc757f5f-8sv8d 1/1 Running 2 12m
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]#
# 重启机器dns不通的话需要删除pod重建就好了
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]# kubectl delete pod coredns-597578ff46-x2s95 -n kube-system
pod "coredns-597578ff46-x2s95" deleted
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]# kubectl exec busybox nslookup baidu.com
kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl exec [POD] -- [COMMAND] instead.
Server: 10.20.0.2
Address 1: 10.20.0.2 kube-dns.kube-system.svc.waluna.local
Name: baidu.com
Address 1: 220.181.38.148
Address 2: 220.181.38.251
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]# kubectl exec busybox nslookup kubernetes
kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl exec [POD] -- [COMMAND] instead.
Server: 10.20.0.2
Address 1: 10.20.0.2 kube-dns.kube-system.svc.waluna.local
Name: kubernetes
Address 1: 10.20.0.1 kubernetes.default.svc.waluna.local
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]# kubectl exec busybox nslookup kubernetes.default.svc.waluna.local
kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl exec [POD] -- [COMMAND] instead.
Server: 10.20.0.2
Address 1: 10.20.0.2 kube-dns.kube-system.svc.waluna.local
Name: kubernetes.default.svc.waluna.local
Address 1: 10.20.0.1 kubernetes.default.svc.waluna.local
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]# kubectl exec busybox nslookup kubernetes.default.svc.waluna.local
kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl exec [POD] -- [COMMAND] instead.
Server: 10.20.0.2
Address 1: 10.20.0.2 kube-dns.kube-system.svc.waluna.local
Name: kubernetes.default.svc.waluna.local
Address 1: 10.20.0.1 kubernetes.default.svc.waluna.local
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]# kubectl exec busybox nslookup kube-dns.kube-system.svc.waluna.local
kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl exec [POD] -- [COMMAND] instead.
Server: 10.20.0.2
Address 1: 10.20.0.2 kube-dns.kube-system.svc.waluna.local
Name: kube-dns.kube-system.svc.waluna.local
Address 1: 10.20.0.2 kube-dns.kube-system.svc.waluna.local
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]# kubectl exec busybox nslookup dashboard-metrics-scraper.kubernetes-dashboard.svc.waluna.local
kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl exec [POD] -- [COMMAND] instead.
Server: 10.20.0.2
Address 1: 10.20.0.2 kube-dns.kube-system.svc.waluna.local
Name: dashboard-metrics-scraper.kubernetes-dashboard.svc.waluna.local
Address 1: 10.20.164.123 dashboard-metrics-scraper.kubernetes-dashboard.svc.waluna.local
[root@k8s-master1 /etc/kubeasz/manifests/dns/coredns]# 打包 kubeasz 项目，方便后期使用
[root@k8s-master1 /etc/kubeasz]# cd /etc/
[root@k8s-master1 /etc]# tar czvf kubeasz-v3.1.1.tar.gz kubeasz/
[root@k8s-master1 /etc]# sz kubeasz-v3.1.1.tar.gz
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