云计算 K8S使用dashboard管理集群

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今年3月份在公司的内部k8s培训会上，开发同事表示使用dashboard的可以满足日常开发需求，例如查看pod的日志，执行exec指令，查看pod的运行状态等，但对basic认证的权限控制表示担忧。
之前介绍过在1.5.2版本上部署dashboard服务，在1.9.1版本离线部署中，也介绍过dashboard服务的RBAC配置和使用技巧。因此本文将在前文基础上完善Heapster的整合与利用token对用户权限进行控制。
dashboard的特点主要如下：
1、能够直观的看到rc、deployment、pod、services等k8s组件的运行情况和日志信息。
2、结合heapster和influxdb后，dashboard的监控图表上可以看到pod的cpu和内存消耗情况。

Heapster介绍

1、Heapster是容器集群监控和性能分析工具，支持Kubernetes和CoreOS。
2、K8S集群的HPA功能的实现就依赖于这些metric数据，HPA将Heapster作为Resource Metrics API，向其获取metric。
3、Kubernetes有个cAdvisor监控（在1.9版本里面，cAdvisor已经和kubelet整合在一起）。
在每个kubernetes Node上都会运行cAdvisor，它会收集本机以及容器的监控数据(cpu,memory,filesystem,network,uptime)。Heapster是一个收集者，Heapster可以收集Node节点上的cAdvisor数据，将每个Node上的cAdvisor的数据进行汇总，还可以按照kubernetes的资源类型来集合资源，比如Pod、Namespace，可以分别获取它们的CPU、内存、网络和磁盘的metric。默认的metric数据聚合时间间隔是1分钟。还可以把数据导入到第三方工具(如InfluxDB)。

Influxdb数据库介绍

2、Influxdb数据库的相关知识介绍，可参考文档：https://www.jianshu.com/p/d2935e99006e
2、如果对Heapster收集到的metric数据没有持久化的需求，可以不配置Influxdb数据库
3、本文Influxdb数据库的存储采用emptydir的方式实现，实际使用过程中，可以选择吧Influxdb数据库部署在k8s集群外部，或者使用其他存储方案。
4、如果有需要的话，还可以集成一个grafana做web展示。Grafana配置可参考文档：https://blog.51cto.com/ylw6006/2084403

一、获取相关镜像

需要科学上网方式获取到dashboard相关的镜像文件，仓库可纳入本地仓库统一管理

#cat/etc/systemd/system/docker.service.d/http-proxy.conf[Service]
Environment="HTTP_PROXY=http://192.168.115.2:1080"#systemctldaemon-reload#systemctlrestartdocker#dockerpullk8s.gcr.io/kubernetes-dashboard-amd64:v1.8.3#dockerpullk8s.gcr.io/heapster-influxdb-amd64:v1.3.3#dockerpullk8s.gcr.io/heapster-amd64:v1.4.2

二、准备配置文件

1、k8s-dashborad-sa.yaml文件，secrct和serviceaccount配置

#catk8s-dashborad-sa.yaml#-------------------DashboardSecret-------------------#apiVersion:v1kind:Secretmetadata:
labels:
k8s-app:kubernetes-dashboard
name:kubernetes-dashboard-certs
namespace:kube-systemtype:Opaque---#-------------------DashboardServiceAccount-------------------#apiVersion:v1kind:ServiceAccountmetadata:
labels:
k8s-app:kubernetes-dashboard
name:kubernetes-dashboard
namespace:kube-system

2、k8s-dashborad-rbac.yaml文件，配置 Role和Role Binding

#catk8s-dashborad-rbac.yaml#-------------------DashboardRole&RoleBinding-------------------#kind:RoleapiVersion:rbac.authorization.k8s.io/v1metadata:
name:kubernetes-dashboard-minimal
namespace:kube-systemrules:
#AllowDashboardtocreate'kubernetes-dashboard-key-holder'secret.-apiGroups:[""]
resources:["secrets"]
verbs:["create"]#AllowDashboardtocreate'kubernetes-dashboard-settings'configmap.-apiGroups:[""]
resources:["configmaps"]
verbs:["create"]#AllowDashboardtoget,updateanddeleteDashboardexclusivesecrets.-apiGroups:[""]
resources:["secrets"]
resourceNames:["kubernetes-dashboard-key-holder","kubernetes-dashboard-certs"]
verbs:["get","update","delete"]#AllowDashboardtogetandupdate'kubernetes-dashboard-settings'configmap.-apiGroups:[""]
resources:["configmaps"]
resourceNames:["kubernetes-dashboard-settings"]
verbs:["get","update"]#AllowDashboardtogetmetricsfromheapster.-apiGroups:[""]
resources:["services"]
resourceNames:["heapster"]
verbs:["proxy"]
-apiGroups:[""]
resources:["services/proxy"]
resourceNames:["heapster","http:heapster:","https:heapster:"]
verbs:["get"]

---apiVersion:rbac.authorization.k8s.io/v1kind:RoleBindingmetadata:
name:kubernetes-dashboard-minimal
namespace:kube-systemroleRef:
apiGroup:rbac.authorization.k8s.io
kind:Role
name:kubernetes-dashboard-minimalsubjects:-kind:ServiceAccount
name:kubernetes-dashboard
namespace:kube-system

3、k8s-dashborad-deployment.yaml配置文件，定义创建pod的模板和副本数

#catk8s-dashborad-deployment.yaml#-------------------DashboardDeployment-------------------#kind:DeploymentapiVersion:apps/v1beta2metadata:
labels:
k8s-app:kubernetes-dashboard
name:kubernetes-dashboard
namespace:kube-systemspec:
replicas:1
revisionHistoryLimit:10
selector:
matchLabels:
k8s-app:kubernetes-dashboard
template:
metadata:
labels:
k8s-app:kubernetes-dashboard
spec:
containers:
-name:kubernetes-dashboard
image:k8s.gcr.io/kubernetes-dashboard-amd64:v1.8.3
ports:
-containerPort:8443
protocol:TCP
args:
---auto-generate-certificates#UncommentthefollowinglinetomanuallyspecifyKubernetesAPIserverHost
#Ifnotspecified,DashboardwillattempttoautodiscovertheAPIserverandconnect
#toit.Uncommentonlyifthedefaultdoesnotwork.
#---apiserver-host=http://my-address:port
volumeMounts:
-name:kubernetes-dashboard-certs
mountPath:/certs#Createon-diskvolumetostoreexeclogs
-mountPath:/tmp
name:tmp-volume
livenessProbe:
httpGet:
scheme:HTTPS
path:/
port:8443
initialDelaySeconds:30
timeoutSeconds:30
volumes:
-name:kubernetes-dashboard-certs
secret:
secretName:kubernetes-dashboard-certs
-name:tmp-volume
emptyDir:{}
serviceAccountName:kubernetes-dashboard#CommentthefollowingtolerationsifDashboardmustnotbedeployedonmaster
tolerations:
-key:node-role.kubernetes.io/master
effect:NoSchedule

4、 k8s-dashborad-service.yaml配置文件，定义service

#catk8s-dashborad-service.yaml#-------------------DashboardService-------------------#kind:ServiceapiVersion:v1metadata:
labels:
k8s-app:kubernetes-dashboard
name:kubernetes-dashboard
namespace:kube-systemspec:
ports:
-port:443
targetPort:8443
nodePort:8490
type:NodePort
selector:
k8s-app:kubernetes-dashboard

三、通过配置文件创建dashboard

#kubectlcreate-f.#kubectlgetpod,deployment,svc-nkube-system

四、配置使用basic认证方式

默认情况下只支持kubeconfig和令牌认证

#echo'admin,admin,1'>/etc/kubernetes/basic_auth_file#grep'auth'/usr/lib/systemd/system/kube-apiserver.service
--authorization-mode=Node,RBAC\\
--runtime-config=rbac.authorization.k8s.io/v1alpha1\\
--enable-bootstrap-token-auth=true\\
--token-auth-file=/etc/kubernetes/token.csv\\
--basic-auth-file=/etc/kubernetes/basic_auth_file\\#grep‘basic’k8s-dashborad-deployment.yaml（配置在args下面）
---authentication-mode=basic#systemctldaemon-reload#systemctlrestartkube-apiserver#kubectlapply-fk8s-dashborad-deployment.yaml

将admin用户和cluter-admin role进行角色绑定

#curl--insecurehttps://vm1:6443-basic-uadmin:admin#kubectlcreateclusterrolebinding\\login-on-dashboard-with-cluster-admin\\
--clusterrole=cluster-admin--user=admin#curl--insecurehttps://vm1:6443-basic-uadmin:admin

五、访问测试

六、整合heapster和influxdb

在没有配置heapster和influxdb的情况下，pod的metric信息是无法获取到的，而早前版本K8S的HPA特性依赖的metric数据来源恰巧就是heapster和influxdb。

1、准备yaml配置文件

#catheapster-sa.yamlapiVersion:v1kind:ServiceAccountmetadata:
name:heapster
namespace:kube-system

#catheapster-rbac.yamlkind:ClusterRoleBindingapiVersion:rbac.authorization.k8s.io/v1beta1metadata:
name:heapsterroleRef:
apiGroup:rbac.authorization.k8s.io
kind:ClusterRole
name:system:heapstersubjects:-kind:ServiceAccount
name:heapster
namespace:kube-system

#catheapster-deployment.yamlapiVersion:extensions/v1beta1
kind:Deployment
metadata:
name:heapsternamespace:kube-system
spec:
replicas:1
template:
metadata:
labels:
task:monitoring
k8s-app:heapster
spec:
serviceAccountName:heapster
containers:
-name:heapster
image:k8s.gcr.io/heapster-amd64:v1.4.2
imagePullPolicy:IfNotPresent
command:
-/heapster
---source=kubernetes:https://kubernetes.default
---sink=influxdb:http://monitoring-influxdb.kube-system.svc:8086

#catheapster-service.yamlapiVersion:v1kind:Servicemetadata:
labels:
task:monitoring
kubernetes.io/cluster-service:'true'
kubernetes.io/name:Heapster
name:heapster
namespace:kube-systemspec:
ports:
-port:80
targetPort:8082
selector:k8s-app:heapster

#catinfluxdb-deployment.yamlapiVersion:extensions/v1beta1kind:Deploymentmetadata:
name:monitoring-influxdb
namespace:kube-systemspec:
replicas:1
template:
metadata:
labels:
task:monitoring
k8s-app:influxdb
spec:
containers:
-name:influxdb
image:k8s.gcr.io/heapster-influxdb-amd64:v1.3.3
volumeMounts:
-mountPath:/data
name:influxdb-storage
volumes:
-name:influxdb-storage
emptyDir:{}

#catinfluxdb-service.yamlapiVersion:v1kind:Servicemetadata:
labels:
task:monitoring
kubernetes.io/cluster-service:'true'
kubernetes.io/name:monitoring-influxdb
name:monitoring-influxdb
namespace:kube-systemspec:
ports:
-port:8086
targetPort:8086
selector:
k8s-app:influxdb

获取heapster中的获取支持的metrics

#kubectlrun-i--ttycurl--namespace=kube-system\\--image=registry.59iedu.com/webwurst/curl-utils/bin/sh
#curlhttp://heapster/api/v1/model/metrics#curlhttp://heapster/api/v1/model/debug/allkeys

#kubectlgetnode#kubectltopnode

当heapster和influxdb pod都正常运行的时候，在dashboard里面就可以看到CPU和内存的监控数据了。

七、配置用户权限

1、删除apiserver里面basic认证相关的配置后重启apiserver
--basic-auth-file=/etc/kubernetes/basic_auth_file

#systemctldaemon-reload#systemctlrestartkube-apiserver

2、删除clusterrolebinding

#kubectldeleteclusterrolebindinglogin-on-dashboard-with-cluster-admin

3、修改k8s-dashborad-deployment.yaml文件
去掉- --authentication-mode=basic参数

4、创建普通用户,赋予所有namespace下资源的get、watch和list权限。
这里通过clusterrole和culsterrolebinding赋予所有namespace相关资源的get、watch、list权限，实际应用环境建议使用创建role和rolebinding指定特定的namespace相关资源权限，各资源权限的赋予规则遵循最小权限原则。

#catrbac-yang.yamlkind:ClusterRoleapiVersion:rbac.authorization.k8s.io/v1metadata:
name:role-yangrules:-apiGroups:[""]
resources:["*"]
verbs:["get","watch","list"]
-apiGroups:["storage.k8s.io"]
resources:["*"]
verbs:["get","watch","list"]
-apiGroups:["rbac.authorization.k8s.io"]
resources:["*"]
verbs:["get","watch","list"]
-apiGroups:["batch"]
resources:["*"]
verbs:["get","watch","list"]
-apiGroups:["apps"]
resources:["*"]
verbs:["get","watch","list"]
-apiGroups:["extensions"]
resources:["*"]
verbs:["get","watch","list"]
---kind:ClusterRoleBindingapiVersion:rbac.authorization.k8s.io/v1metadata:
name:role-bind-yangsubjects:-kind:ServiceAccount
name:yang
namespace:kube-systemroleRef:
kind:ClusterRole
name:role-yang
apiGroup:rbac.authorization.k8s.io

#kubectlcreatesayang-nkube-system#kubectlcreate-frbac-yang.yaml#kubectl-nkube-systemdescribesecret$(kubectl-nkube-systemgetsecret|grepyang|awk'{print$1}')

5、测试普通用户的权限




6、创建super用户admin

#kubectlcreatesaadmin-nkube-system#catrbac-admin.yamlapiVersion:rbac.authorization.k8s.io/v1beta1
kind:ClusterRoleBinding
metadata:
name:admin
roleRef:
apiGroup:rbac.authorization.k8s.io
kind:ClusterRole
name:cluster-admin
subjects:
-kind:ServiceAccount
name:admin
namespace:kube-system#kubectlcreate-frbac-admin.yaml#kubectl-nkube-systemdescribesecret$(kubectl-nkube-systemgetsecret|grepadmin|awk'{print$1}')

使用admin用户的token登陆后继承cluster-admin的权限

参考：
https://github.com/kubernetes/dashboard/wiki/Creating-sample-user
https://github.com/kubernetes/dashboard/wiki/Access-control
https://github.com/kubernetes/heapster/blob/master/docs/model.md

本文标题：K8S使用dashboard管理集群
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