Kubernets二进制安装(15)之安装部署coredns

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在运维主机上(mfyxw50.mfyxw.com)准备Coredns镜像文件，以docker镜像文件的方式部署到Kubernetes集群中去。

1.下载coredns镜像

[root@mfyxw50 ~]# docker pull coredns/coredns:1.6.9 [root@mfyxw50 ~]# docker tag faac9e62c0d6 harbor.od.com/public/coredns:v1.6.9

2.将打好标签的coredns上传到私有仓库

[root@mfyxw50 ~]# docker login harbor.od.com [root@mfyxw50 ~]# docker push harbor.od.com/public/coredns:v1.6.9

3.登录harbor.od.com查看是否上传成功

登录到https://harbor.od.com，使用用户名：admin 密码：Harbor12345来查看coredns是否上传成功

4.提供coredns的yaml文件(通过http方式访问，给nginx提供配置文件)

在运维主机(mfyxw50.mfyxw.com)执行

[root@mfyxw50 ~]# cat > /etc/nginx/conf.d/k8s-yaml.od.com.conf << EOF server { listen 80; server_name k8s-yaml.od.com; location / { autoindex on; default_type text/plain; root /data/k8s-yaml; } } EOF

5.创建k8s-yaml目录并重启nginx服务

在运维主机(mfyxw50.mfyxw.com)上执行如下命令

以后所有的资源配置清单统一放置在运维主机的/data/k8s-yaml目录下即可

[root@mfyxw50 ~]# mkdir -p /data/k8s-yaml/coredns [root@mfyxw50 ~]# /usr/sbin/nginx -s reload

6.在DNS的od配置文件添加记录

在DNS服务器(mfyxw10.mfyxw.com)主机上执行如下命令

[root@mfyxw10 ~]# cat > /var/named/od.com.zone << EOF \$ORIGIN od.com. \$TTL 600 ; 10 minutes @ IN SOA dns.od.com. dnsadmin.od.com. ( ;序号请加1，表示比之前版本要新 2020031304 ; serial 10800 ; refresh (3 hours) 900 ; retry (15 minutes) 604800 ; expire (1 week) 86400 ; minimum (1 day) ) NS dns.od.com. \$TTL 60 ; 1 minute dns A 192.168.80.10 harbor A 192.168.80.50 ;添加harbor记录 k8s-yaml A 192.168.80.50 EOF

7.重启DNS服务

在DNS服务器(mfyxw10.mfyxw.com)主机执行如下命令

[root@mfyxw10 ~]# systemctl restart named [root@mfyxw10 ~]# ping k8s-yaml.od.com

8.访问k8s-yaml.od.com/coredns

9.为coredns提供yaml文件

在运维主机(mfyxw50.mfyxw.com)上执行

rbac.yaml文件内容如下：

[root@mfyxw50 ~]# cat > /data/k8s-yaml/coredns/rbac.yaml << EOF apiVersion: v1 kind: ServiceAccount metadata: name: coredns namespace: kube-system labels: kubernetes.io/cluster-service: "true" addonmanager.kubernetes.io/mode: Reconcile --- apiVersion: rbac.authorization.k8s.io/v1 kind: ClusterRole metadata: labels: kubernetes.io/bootstrapping: rbac-defaults addonmanager.kubernetes.io/mode: Reconcile name: system:coredns rules: - apiGroups: - "" resources: - endpoints - services - pods - namespaces verbs: - list - watch --- apiVersion: rbac.authorization.k8s.io/v1 kind: ClusterRoleBinding metadata: annotations: rbac.authorization.kubernetes.io/autoupdate: "true" labels: kubernetes.io/bootstrapping: rbac-defaults addonmanager.kubernetes.io/mode: EnsureExists name: system:coredns roleRef: apiGroup: rbac.authorization.k8s.io kind: ClusterRole name: system:coredns subjects: - kind: ServiceAccount name: coredns namespace: kube-system EOF

configMap.yaml文件内容如下：

[root@mfyxw50 ~]# cat > /data/k8s-yaml/coredns/configMap.yaml << EOF apiVersion: v1 kind: ConfigMap metadata: name: coredns namespace: kube-system data: Corefile: | .:53 { errors log health ready kubernetes cluster.local 172.16.0.0/16 forward . 192.168.80.10 cache 30 loop reload loadbalance } EOF

deployment.yaml文件内容如下：

[root@mfyxw50 ~]# cat > /data/k8s-yaml/coredns/deployment.yaml << EOF apiVersion: apps/v1 kind: Deployment metadata: name: coredns namespace: kube-system labels: k8s-app: coredns kubernetes.io/name: "CoreDNS" spec: replicas: 1 selector: matchLabels: k8s-app: coredns template: metadata: labels: k8s-app: coredns spec: priorityClassName: system-cluster-critical serviceAccountName: coredns containers: - name: coredns image: harbor.od.com/public/coredns:v1.6.9 args: - -conf - /etc/coredns/Corefile volumeMounts: - name: config-volume mountPath: /etc/coredns ports: - containerPort: 53 name: dns protocol: UDP - containerPort: 53 name: dns-tcp protocol: TCP - containerPort: 9153 name: metrics protocol: TCP livenessProbe: httpGet: path: /health port: 8080 scheme: HTTP initialDelaySeconds: 60 timeoutSeconds: 5 successThreshold: 1 failureThreshold: 5 dnsPolicy: Default volumes: - name: config-volume configMap: name: coredns items: - key: Corefile path: Corefile EOF

svc.yaml文件内容如下：

[root@mfyxw50 ~]# cat > /data/k8s-yaml/coredns/svc.yaml << EOF apiVersion: v1 kind: Service metadata: name: coredns namespace: kube-system labels: k8s-app: coredns kubernetes.io/cluster-service: "true" kubernetes.io/name: "CoreDNS" spec: selector: k8s-app: coredns clusterIP: 172.16.0.2 ports: - name: dns port: 53 protocol: UDP - name: dns-tcp port: 53 - name: metrics port: 9153 protocol: TCP EOF

10.执行coredns的yaml文件

在master主机(mfyxw30.mfyxw.com或mfyxw40.mfyxw.com)任意一台执行

[root@mfyxw30 ~]# kubectl apply -f http://k8s-yaml.od.com/coredns/rbac.yaml [root@mfyxw30 ~]# kubectl apply -f http://k8s-yaml.od.com/coredns/configMap.yaml [root@mfyxw30 ~]# kubectl apply -f http://k8s-yaml.od.com/coredns/deployment.yaml [root@mfyxw30 ~]# kubectl apply -f http://k8s-yaml.od.com/coredns/svc.yaml

11.在宿主机执行dig命令查询(宿主机查询)

在master主机(mfyxw30.mfyxw.com或mfyxw40.mfyxw.com)任意一台执行

[root@mfyxw30 ~]# kubectl get svc [root@mfyxw30 ~]# dig -t A nginx-ds.default.svc.cluster.local. @172.16.0.2 +short [root@mfyxw30 ~]# dig -t A kubernetes.default.svc.cluster.local. @172.16.0.2 +short

12.使用curl来访问

在master主机(mfyxw30.mfyxw.com或mfyxw40.mfyxw.com)任意一台执行

[root@mfyxw30 ~]# curl nginx-ds.default [root@mfyxw30 ~]# curl nginx-ds.default.svc.cluster.local

在集群外面(宿主机上)curl是无法访问到

进入容器里面curl是否能正常访问到呢？

[root@mfyxw30 ~]# kubectl get svc [root@mfyxw30 ~]# kubectl get pod [root@mfyxw30 ~]# kubectl exec -it nginx-ns-8sgh4 -- /bin/bash root@nginx-ns-8sgh4:/# curl nginx-ds.default.svc.cluster.local