——> 课程视频同步分享在今日头条和B站
大家好，我是博哥爱运维，在k8s上我们如何控制访问权限呢，答案就是Role-based access control (RBAC) – 基于角色（Role）的访问控制，（RBAC）是一种基于组织中用户的角色来调节控制对 计算机或网络资源的访问的方法。
在早期的K8s版本，RBAC还未出现的时候，整个K8s的安全是较为薄弱的，有了RBAC后，我们可以对K8s集群的访问人员作非常明细化的控制，控制他们能访问什么资源，以只读还是可以读写的形式来访问，目前RBAC是K8s默认的安全授权标准，所以我们非常有必要来掌握RBAC的使用，这样才有更有力的保障我们的K8s集群的安全使用，下面我们将以生产中的实际使用来大家了解及掌握RBAC的生产应用。
RBAC里面的几种资源关系图，下面将用下面的资源来演示生产中经典的RBAC应用
|--- Role --- RoleBinding只在指定namespace中生效ServiceAccount ---||--- ClusterRole --- ClusterRoleBinding不受namespace限制，在整个K8s集群中生效在我看来，RBAC在K8s上的用途主要分为两大类：
第一类是保证在K8s上运行的pod服务具有相应的集群权限，如gitlab的CI/CD，它需要能访问除自身以外其他pod，比如gitlab-runner的pod的权限，再比如gitlab-runner的pod需要拥有创建新的临时pod的权限，用以来构建CI/CD自动化流水线，这里大家没用过不懂没关系，先简单了解下就可以了，在本课程后面基于K8s及gitlab的生产实战CI/CD内容会给大家作详细实战讲解；
第二类是创建能访问K8s相应资源、拥有对应权限的kube-config配置给到使用K8s的人员，来作为连接K8s的授权凭证
第一类的实战这里先暂时以早期的helm2来作下讲解，helm是一个快捷安装K8s各类资源的管理工具，通过之前给大家讲解的，一个较为完整的服务可能会存在deployment，service，configmap，secret，ingress等资源来组合使用，大家在用的过程中可能会觉得配置使用较为麻烦，这时候helm就出现了，它把这些资源都打包封装成它自己能识别的内容，我们在安装一个服务的时候，就只需要作下简单的配置，一条命令即可完成上述众多资源的配置安装，titller相当于helm的服务端，它是需要有权限在K8s中创建各类资源的，在初始安装使用时，如果没有配置RBAC权限，我们会看到如下报错：
root@node1:~# helm install stable/mysqlError: no available release name found这时，我们可以来快速解决这个问题，创建sa关联K8s自带的最高权限的ClusterRole（生产中建议不要这样做，权限太高有安全隐患，这个就和linux的root管理帐号一样，一般都是建议通过sudo来控制帐号权限）
kubectl create serviceaccount --namespace kube-system tillerkubectl create clusterrolebinding tiller-cluster-rule --clusterrole=cluster-admin --serviceaccount=kube-system:tillerkubectl patch deploy --namespace kube-system tiller-deploy -p '{"spec":{"template":{"spec":{"serviceAccount":"tiller"}}}}'第二类，我这里就直接以我在生产中实施的完整脚本来做讲解及实战，相信会给大家带来一个全新的学习感受，并能很快掌握它们：
- 创建对指定namespace有只读权限的kube-config
#!/bin/bashexport KUBECONFIG=/root/.kube/configBASEDIR="$(dirname "$0")"folder="$BASEDIR/kube_config"echo -e "All namespaces is here: \n$(kubectl get ns|awk 'NR!=1{print $1}')"echo "endpoint server if local network you can use $(kubectl cluster-info |awk '/Kubernetes/{print $NF}')"clustername=$1endpoint=$(echo "$2" | sed -e 's,https\?://,,g')if [[ -z "$endpoint" || -z "$clustername" ]]; thenecho "Use "$(basename "$0")" CLUSTERNAME ENDPOINT";exit 1;fi# https://github.com/kubernetes/kubernetes/blob/master/CHANGELOG/CHANGELOG-1.24.md#urgent-upgrade-notesecho "---apiVersion: v1kind: ServiceAccountmetadata:name: all-readonly-${clustername}namespace: kube-system---apiVersion: v1kind: Secretmetadata:name: all-readonly-secret-sa-$clustername-usernamespace: kube-systemannotations:kubernetes.io/service-account.name: "all-readonly-${clustername}"type: kubernetes.io/service-account-token---apiVersion: rbac.authorization.k8s.io/v1kind: ClusterRolemetadata:name: all-readonly-${clustername}rules:- apiGroups:- ''resources:- configmaps- endpoints- persistentvolumes- persistentvolumeclaims- pods- replicationcontrollers- replicationcontrollers/scale- serviceaccounts- services- nodesverbs:- get- list- watch- apiGroups:- ''resources:- bindings- events- limitranges- namespaces/status- pods/log- pods/status- replicationcontrollers/status- resourcequotas- resourcequotas/statusverbs:- get- list- watch- apiGroups:- ''resources:- namespacesverbs:- get- list- watch- apiGroups:- appsresources:- controllerrevisions- daemonsets- deployments- deployments/scale- replicasets- replicasets/scale- statefulsets- statefulsets/scaleverbs:- get- list- watch- apiGroups:- autoscalingresources:- horizontalpodautoscalersverbs:- get- list- watch- apiGroups:- batchresources:- cronjobs- jobsverbs:- get- list- watch- apiGroups:- extensionsresources:- daemonsets- deployments- deployments/scale- ingresses- networkpolicies- replicasets- replicasets/scale- replicationcontrollers/scaleverbs:- get- list- watch- apiGroups:- policyresources:- poddisruptionbudgetsverbs:- get- list- watch- apiGroups:- networking.k8s.ioresources:- networkpoliciesverbs:- get- list- watch- apiGroups:- metrics.k8s.ioresources:- podsverbs:- get- list- watch- apiGroups:- storage.k8s.ioresources:- storageclassesverbs:- get- list- watch---apiVersion: rbac.authorization.k8s.io/v1kind: ClusterRoleBindingmetadata:name: all-readonly-${clustername}roleRef:apiGroup: rbac.authorization.k8s.iokind: ClusterRolename: all-readonly-${clustername}subjects:- kind: ServiceAccountname: all-readonly-${clustername}namespace: kube-system" | kubectl apply -f -mkdir -p $folder#tokenName=$(kubectl get sa all-readonly-${clustername} -n $namespace -o "jsonpath={.secrets[0].name}")tokenName="all-readonly-secret-sa-$clustername-user"token=$(kubectl get secret $tokenName -n kube-system -o "jsonpath={.data.token}" | base64 --decode)certificate=$(kubectl get secret $tokenName -n kube-system -o "jsonpath={.data['ca\.crt']}")echo "apiVersion: v1kind: Configpreferences: {}clusters:- cluster:certificate-authority-data: $certificateserver: https://$endpointname: all-readonly-${clustername}users:- name: all-readonly-${clustername}user:as-user-extra: {}client-key-data: $certificatetoken: $tokencontexts:- context:cluster: all-readonly-${clustername}user: all-readonly-${clustername}name: ${clustername}current-context: ${clustername}" > $folder/${clustername}-all-readonly.conf- 创建对指定namespace有所有权限的kube-config（在已有的namespace中创建）
#!/bin/bashexport KUBECONFIG=/root/.kube/configBASEDIR="$(dirname "$0")"folder="$BASEDIR/kube_config"echo -e "All namespaces is here: \n$(kubectl get ns|awk 'NR!=1{print $1}')"echo "endpoint server if local network you can use $(kubectl cluster-info |awk '/Kubernetes/{print $NF}')"namespace=$1endpoint=$(echo "$2" | sed -e 's,https\?://,,g')if [[ -z "$endpoint" || -z "$namespace" ]]; thenecho "Use "$(basename "$0")" NAMESPACE ENDPOINT";exit 1;fi# https://github.com/kubernetes/kubernetes/blob/master/CHANGELOG/CHANGELOG-1.24.md#urgent-upgrade-notesecho "---apiVersion: v1kind: ServiceAccountmetadata:name: $namespace-usernamespace: $namespace---apiVersion: v1kind: Secretmetadata:name: secret-sa-$namespace-usernamespace: $namespaceannotations:kubernetes.io/service-account.name: "$namespace-user"type: kubernetes.io/service-account-token---kind: RoleapiVersion: rbac.authorization.k8s.io/v1metadata:name: $namespace-user-full-accessnamespace: $namespacerules:- apiGroups: ['', 'extensions', 'apps', 'metrics.k8s.io', 'networking.k8s.io']resources: ['*']verbs: ['*']- apiGroups: ['batch']resources:- jobs- cronjobsverbs: ['*']---kind: RoleBindingapiVersion: rbac.authorization.k8s.io/v1metadata:name: $namespace-user-viewnamespace: $namespacesubjects:- kind: ServiceAccountname: $namespace-usernamespace: $namespaceroleRef:apiGroup: rbac.authorization.k8s.iokind: Rolename: $namespace-user-full-access" | kubectl apply -f -mkdir -p $folder#tokenName=$(kubectl get sa $namespace-user -n $namespace -o "jsonpath={.secrets[0].name}")tokenName="secret-sa-$namespace-user"token=$(kubectl get secret $tokenName -n $namespace -o "jsonpath={.data.token}" | base64 --decode)certificate=$(kubectl get secret $tokenName -n $namespace -o "jsonpath={.data['ca\.crt']}")echo "apiVersion: v1kind: Configpreferences: {}clusters:- cluster:certificate-authority-data: $certificateserver: https://$endpointname: $namespace-clusterusers:- name: $namespace-useruser:as-user-extra: {}client-key-data: $certificatetoken: $tokencontexts:- context:cluster: $namespace-clusternamespace: $namespaceuser: $namespace-username: $namespacecurrent-context: $namespace" > $folder/$namespace.kube.conf- 在已有sa上附加其他命名空间的权限
# same ServiceAccount:" test-a-user " default can contorl my own namespace:" test-a " and config later to contorl other namespace: "test-b"apiVersion: rbac.authorization.k8s.io/v1kind: Rolemetadata:name: test-b-user-full-accessnamespace: test-brules:- apiGroups: ['', 'extensions', 'apps', 'metrics.k8s.io', 'networking.k8s.io']resources: ['*']verbs: ['*']- apiGroups: ['batch']resources:- jobs- cronjobsverbs: ['*']---apiVersion: rbac.authorization.k8s.io/v1kind: RoleBindingmetadata:name: test-b-user-full-access-both-test-a-usernamespace: test-broleRef:apiGroup: rbac.authorization.k8s.iokind: Rolename: test-b-user-full-accesssubjects:- kind: ServiceAccountname: test-a-usernamespace: test-a