如果没有特殊指明，所有操作均在 zhaoyixin-k8s-01 节点上执行。
插件是集群的附件组件，丰富和完善了集群的功能。
1.部署 coredns 插件
下载和配置 coredns
cd /opt/k8s/work
git clone https://github.com/coredns/deployment.git
mv deployment coredns-deployment
创建 coredns
cd /opt/k8s/work/coredns-deployment/kubernetes
source /opt/k8s/bin/environment.sh
./deploy.sh -i ${CLUSTER_DNS_SVC_IP} -d ${CLUSTER_DNS_DOMAIN} | kubectl apply -f -
检查 coredns 功能
$ kubectl get all -n kube-system -l k8s-app=kube-dns
NAME READY STATUS RESTARTS AGE
pod/coredns-59c6ddbf5d-fs4nh 1/1 Running 0 44s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/kube-dns ClusterIP 10.254.0.2 <none> 53/UDP,53/TCP,9153/TCP 44s
NAME READY UP-TO-DATE AVAILABLE AGE
deployment.apps/coredns 1/1 1 1 44s
NAME DESIRED CURRENT READY AGE
replicaset.apps/coredns-59c6ddbf5d 1 1 1 45s
新建一个 Deployment：
cd /opt/k8s/work
cat > my-nginx.yaml <<EOF
apiVersion: apps/v1
kind: Deployment
metadata:
name: my-nginx
spec:
replicas: 2
selector:
matchLabels:
run: my-nginx
template:
metadata:
labels:
run: my-nginx
spec:
containers:
- name: my-nginx
image: nginx:1.7.9
ports:
- containerPort: 80
EOF
kubectl create -f my-nginx.yaml
expose 该 Deployment，生成 my-nginx 服务：
$ kubectl expose deploy my-nginx
service/my-nginx exposed
$ kubectl get services my-nginx -o wide
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
my-nginx ClusterIP 10.254.239.51 <none> 80/TCP 14s run=my-nginx
创建另一个 Pod，查看 /etc/resolv.conf 是否包含 kubelet 配置的 --cluster-dns 和 --cluster-domain，是否能够将服务 my-nginx 解析到上面显示的 Cluster IP 10.254.239.51
cd /opt/k8s/work
cat > dnsutils-ds.yml <<EOF
apiVersion: v1
kind: Service
metadata:
name: dnsutils-ds
labels:
app: dnsutils-ds
spec:
type: NodePort
selector:
app: dnsutils-ds
ports:
- name: http
port: 80
targetPort: 80
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: dnsutils-ds
labels:
addonmanager.kubernetes.io/mode: Reconcile
spec:
selector:
matchLabels:
app: dnsutils-ds
template:
metadata:
labels:
app: dnsutils-ds
spec:
containers:
- name: my-dnsutils
image: tutum/dnsutils:latest
command:
- sleep
- "3600"
ports:
- containerPort: 80
EOF
kubectl create -f dnsutils-ds.yml
$ kubectl get pods -lapp=dnsutils-ds -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
dnsutils-ds-45nbv 1/1 Running 0 2m16s 172.30.219.4 zhaoyixin-k8s-02 <none> <none>
dnsutils-ds-ghc6l 1/1 Running 0 2m16s 172.30.180.67 zhaoyixin-k8s-01 <none> <none>
dnsutils-ds-jgwvg 1/1 Running 0 2m16s 172.30.200.4 zhaoyixin-k8s-03 <none> <none>
$ kubectl -it exec dnsutils-ds-45nbv cat /etc/resolv.conf
search default.svc.cluster.local svc.cluster.local cluster.local openstacklocal
nameserver 10.254.0.2
options ndots:5
$ kubectl -it exec dnsutils-ds-45nbv nslookup kubernetes
Server: 10.254.0.2
Address: 10.254.0.2#53
Name: kubernetes.default.svc.cluster.local
Address: 10.254.0.1
$ kubectl -it exec dnsutils-ds-45nbv nslookup www.baidu.com
Server: 10.254.0.2
Address: 10.254.0.2#53
Non-authoritative answer:
www.baidu.com canonical name = www.a.shifen.com.
Name: www.a.shifen.com
Address: 163.177.151.110
Name: www.a.shifen.com
Address: 163.177.151.109
$ kubectl -it exec dnsutils-ds-45nbv nslookup www.baidu.com.
Server: 10.254.0.2
Address: 10.254.0.2#53
Non-authoritative answer:
www.baidu.com canonical name = www.a.shifen.com.
Name: www.a.shifen.com
Address: 163.177.151.109
Name: www.a.shifen.com
Address: 163.177.151.110
$ kubectl -it exec dnsutils-ds-45nbv nslookup my-nginx
Server: 10.254.0.2
Address: 10.254.0.2#53
Name: my-nginx.default.svc.cluster.local
Address: 10.254.239.51
可以看到，pod 中将服务 my-nginx 正确得解析到了 Cluster IP 10.254.239.51 上。
2.部署 Dashboard 插件
下载和修改配置文件
cd /opt/k8s/work
wget https://raw.githubusercontent.com/kubernetes/dashboard/v2.0.0-rc4/aio/deploy/recommended.yaml
mv recommended.yaml dashboard-recommended.yaml
执行所有定义文件
cd /opt/k8s/work
kubectl apply -f dashboard-recommended.yaml
查看运行状态
$ kubectl get pods -n kubernetes-dashboard
NAME READY STATUS RESTARTS AGE
dashboard-metrics-scraper-7b8b58dc8b-l2vrq 1/1 Running 0 5m39s
kubernetes-dashboard-6cfc8c4c9-gvp7n 1/1 Running 0 5m41s
访问 dashboard
从 1.7 开始，dashboard 只允许通过 https 访问，如果使用 kube proxy 则必须监听 localhost 或 127.0.0.1。对于 NodePort 没有这个限制，但是仅建议在开发环境中使用。对于不满足这些条件的登录访问，在登录成功后浏览器不跳转，始终停在登录界面。
通过 port forward 访问 dashboard
启动端口转发：
[root@zhaoyixin-k8s-01 work] kubectl port-forward -n kubernetes-dashboard svc/kubernetes-dashboard 14443:443 --address 0.0.0.0
浏览器访问 URL：https://192.168.16.8:14443
创建登录 Dashboard 的 token 和 kubeconfig 配置文件
dashboard 默认只支持 token 认证（不支持 client 证书认证），所以如果使用 Kubeconfig 文件，需要将 token 写入到该文件。
创建登录 token
kubectl create sa dashboard-admin -n kube-system
kubectl create clusterrolebinding dashboard-admin --clusterrole=cluster-admin --serviceaccount=kube-system:dashboard-admin
ADMIN_SECRET=$(kubectl get secrets -n kube-system | grep dashboard-admin | awk '{print $1}')
DASHBOARD_LOGIN_TOKEN=$(kubectl describe secret -n kube-system ${ADMIN_SECRET} | grep -E '^token' | awk '{print $2}')
echo ${DASHBOARD_LOGIN_TOKEN}
使用输出的 token 登录 Dashboard。
创建使用 token 的 KubeConfig 文件
source /opt/k8s/bin/environment.sh
# 设置集群参数
kubectl config set-cluster kubernetes
--certificate-authority=/etc/kubernetes/cert/ca.pem
--embed-certs=true
--server=${KUBE_APISERVER}
--kubeconfig=dashboard.kubeconfig
# 设置客户端认证参数，使用上面创建的 Token
kubectl config set-credentials dashboard_user
--token=${DASHBOARD_LOGIN_TOKEN}
--kubeconfig=dashboard.kubeconfig
# 设置上下文参数
kubectl config set-context default
--cluster=kubernetes
--user=dashboard_user
--kubeconfig=dashboard.kubeconfig
# 设置默认上下文
kubectl config use-context default --kubeconfig=dashboard.kubeconfig
用生成的 dashboard.kubeconfig 登录 Dashboard。