4.kubernetes的服务发现插件-CoreDNS

1.1.部署K8S内网资源清单http服务

1.2.部署coredns

部署K8S内网资源清单http服务

在运维主机HDSS7-200.host.com上,配置一个nginx虚拟主机,用以提高k8s统一的资源配置清单访问入口

配置nginx

[root@hdss7- ~]# vi /etc/nginx/conf.d/k8s-yaml.fx.com.conf

server {

    listen       ;

    server_name  k8s-yaml.fx.com;

    location / {

        autoindex on;

        default_type text/plain;

        root /data/k8s-yaml;

    }

}

[root@hdss7- ~]# nginx -t

nginx: the configuration file /etc/nginx/nginx.conf syntax is ok

nginx: configuration file /etc/nginx/nginx.conf test is successful

[root@hdss7- ~]# nginx -s reload

[root@hdss7- ~]# cd /data

[root@hdss7- data]# mkdir k8s-yaml

[root@hdss7- data]# cd k8s-yaml/

[root@hdss7- k8s-yaml]# mkdir coredns

[root@hdss7- k8s-yaml]#

配置dns解析

[root@hdss7- ~]# vi /var/named/fx.com.zone

$ORIGIN fx.com.

$TTL         ;  minutes

@               IN SOA  dns.fx.com. dnsadmin.fx.com. (

                          ; serial

                               ; refresh ( hours)

                                 ; retry ( minutes)

                              ; expire ( week)

                               ; minimum ( day)

                         )

                        NS      dns.fx.com.

$TTL  ;  minute

dns             A       10.4.7.11

harbor          A       10.4.7.200

k8s-yaml        A       10.4.7.200

[root@hdss7- ~]# systemctl restart named

[root@hdss7- ~]# dig -t A k8s-yaml.fx.com @10.4.7.11 +short

10.4.7.200

下载coredns(docker)镜像并打包上传到harbor仓库

[root@hdss7- k8s-yaml]# docker pull coredns/coredns:1.6.

[root@hdss7- k8s-yaml]# docker tag c0f6e815079e harbor.fx.com/public/coredns:v1.6.1

[root@hdss7- k8s-yaml]# docker push harbor.fx.com/public/coredns:v1.6.1

准备资源配置清单

[root@hdss7- ~]#  mkdir -p /data/k8s-yaml/coredns && cd /data/k8s-yaml/coredns/

rbac.yaml

[root@hdss7- coredns]# vi rbac.yaml

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

configmap.yaml

[root@hdss7- coredns]# vi cm.yaml

apiVersion: v1

kind: ConfigMap

metadata:

  name: coredns

  namespace: kube-system

data:

  Corefile: |

    .: {

        errors

        log

        health

        ready

        kubernetes cluster.local 192.168.0.0/

        forward . 10.4.7.11

        cache

        loop

        reload

        loadbalance

       }

dp.yaml

[root@hdss7- coredns]# vi dp.yaml

apiVersion: apps/v1

kind: Deployment

metadata:

  name: coredns

  namespace: kube-system

  labels:

    k8s-app: coredns

    kubernetes.io/name: "CoreDNS"

spec:

  replicas:

  selector:

    matchLabels:

      k8s-app: coredns

  template:

    metadata:

      labels:

        k8s-app: coredns

    spec:

      priorityClassName: system-cluster-critical

      serviceAccountName: coredns

      containers:

      - name: coredns

        image: harbor.fx.com/public/coredns:v1.6.1

        args:

        - -conf

        - /etc/coredns/Corefile

        volumeMounts:

        - name: config-volume

          mountPath: /etc/coredns

        ports:

        - containerPort:

          name: dns

          protocol: UDP

        - containerPort:

          name: dns-tcp

          protocol: TCP

        - containerPort:

          name: metrics

          protocol: TCP

        livenessProbe:

          httpGet:

            path: /health

            port:

            scheme: HTTP

          initialDelaySeconds:

          timeoutSeconds:

          successThreshold:

          failureThreshold:

      dnsPolicy: Default

      volumes:

        - name: config-volume

          configMap:

            name: coredns

            items:

            - key: Corefile

              path: Corefile

svc.yaml

[root@hdss7- coredns]# vi svc.yaml

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: 192.168.0.2

  ports:

  - name: dns

    port:

    protocol: UDP

  - name: dns-tcp

    port:

  - name: metrics

    port:

    protocol: TCP

应用资源配置清单

[root@hdss7- ~]# kubectl apply -f http://k8s-yaml.fx.com/coredns/rbac.yaml

serviceaccount/coredns created

clusterrole.rbac.authorization.k8s.io/system:coredns created

clusterrolebinding.rbac.authorization.k8s.io/system:coredns created

[root@hdss7- ~]# kubectl apply -f http://k8s-yaml.fx.com/coredns/cm.yaml

configmap/coredns created

[root@hdss7- ~]# kubectl apply -f http://k8s-yaml.fx.com/coredns/dp.yaml

deployment.apps/coredns created

[root@hdss7- ~]# kubectl apply -f http://k8s-yaml.fx.com/coredns/svc.yaml

service/coredns created

[root@hdss7- ~]# kubectl get all -n kube-system

NAME                           READY   STATUS    RESTARTS   AGE

pod/coredns-65cb567d6f-4x5tn   /     Running             32s

NAME              TYPE        CLUSTER-IP    EXTERNAL-IP   PORT(S)                  AGE

service/coredns   ClusterIP   192.168.0.2   <none>        /UDP,/TCP,/TCP   26s

NAME                      READY   UP-TO-DATE   AVAILABLE   AGE

deployment.apps/coredns   /                            32s

NAME                                 DESIRED   CURRENT   READY   AGE

replicaset.apps/coredns-65cb567d6f                            32s

验证coredns

[root@hdss7- ~]# dig -t A www.baidu.com @192.168.0.2 +short

www.a.shifen.com.

220.181.38.150

220.181.38.149

[root@hdss7- ~]# kubectl get svc -n kube-public

NAME       TYPE        CLUSTER-IP        EXTERNAL-IP   PORT(S)   AGE

nginx-dp   ClusterIP   192.168.164.107   <none>        /TCP    28h

[root@hdss7- ~]# dig -t A nginx-dp.kube-public.svc.cluster.local. @192.168.0.2 +short

192.168.164.107

[root@hdss7- ~]# kubectl get pods -o wide

NAME             READY   STATUS    RESTARTS   AGE     IP           NODE                NOMINATED NODE   READINESS GATES

nginx-ds-ffw5x   /     Running             3h48m   172.7.22.2   hdss7-.host.com   <none>           <none>

nginx-ds-t2scb   /     Running             3h47m   172.7.21.2   hdss7-.host.com   <none>           <none>

[root@hdss7- ~]# kubectl exec -it nginx-ds-ffw5x /bin/bash

root@nginx-ds-ffw5x:/# curl nginx-dp.kube-public

<!DOCTYPE html>

<html>

<head>

<title>Welcome to nginx!</title>

<style>

    body {

        width: 35em;

        margin:  auto;

        font-family: Tahoma, Verdana, Arial, sans-serif;

    }

</style>

</head>

<body>

<h1>Welcome to nginx!</h1>

<p>If you see this page, the nginx web server is successfully installed and

working. Further configuration is required.</p>

<p>For online documentation and support please refer to

<a href="http://nginx.org/">nginx.org</a>.<br/>

Commercial support is available at

<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>

</body>

</html>

巴特西

4.kubernetes的服务发现插件-CoreDNS

下载coredns(docker)镜像并打包上传到harbor仓库

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