K8S的RBAC鉴权
K8S自1.6版本起默认使用基于角色的访问控制（RBAC）
相较于ABAC（基于属性的访问控制）和WebHook等鉴权机制：
- 对集群中的资源的权限实现了完整覆盖
- 支持权限的动态调整，无需重启apiserver
基于角色的访问控制图
查看账号
[root@hdss7-21 ~]# kubectl get clusterrole
NAME AGE
admin 19d
cluster-admin 19d
edit 19d
system:aggregate-to-admin 19d
system:aggregate-to-edit 19d
system:aggregate-to-view 19d
system:auth-delegator 19d
system:basic-user 19d
system:certificates.k8s.io:certificatesigningrequests:nodeclient 19d
system:certificates.k8s.io:certificatesigningrequests:selfnodeclient 19d
system:controller:attachdetach-controller 19d
system:controller:certificate-controller 19d
system:controller:clusterrole-aggregation-controller 19d
system:controller:cronjob-controller 19d
system:controller:daemon-set-controller 19d
system:controller:deployment-controller 19d
system:controller:disruption-controller 19d
system:controller:endpoint-controller 19d
system:controller:expand-controller 19d
system:controller:generic-garbage-collector 19d
system:controller:horizontal-pod-autoscaler 19d
system:controller:job-controller 19d
system:controller:namespace-controller 19d
system:controller:node-controller 19d
system:controller:persistent-volume-binder 19d
system:controller:pod-garbage-collector 19d
system:controller:pv-protection-controller 19d
system:controller:pvc-protection-controller 19d
system:controller:replicaset-controller 19d
system:controller:replication-controller 19d
system:controller:resourcequota-controller 19d
system:controller:route-controller 19d
system:controller:service-account-controller 19d
system:controller:service-controller 19d
system:controller:statefulset-controller 19d
system:controller:ttl-controller 19d
system:coredns 22h
system:csi-external-attacher 19d
system:csi-external-provisioner 19d
system:discovery 19d
system:heapster 19d
system:kube-aggregator 19d
system:kube-controller-manager 19d
system:kube-dns 19d
system:kube-scheduler 19d
system:kubelet-api-admin 19d
system:node 19d
system:node-bootstrapper 19d
system:node-problem-detector 19d
system:node-proxier 19d
system:persistent-volume-provisioner 19d
system:public-info-viewer 19d
system:volume-scheduler 19d
traefik-ingress-controller 11h
view 19d
可以看到system开头的都是集群角色，而traefik-ingress-controller是我们自己创建的。
再查看cluster-admin账户
[root@hdss7-21 ~]# kubectl get clusterrole cluster-admin -o yaml
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
annotations:
rbac.authorization.kubernetes.io/autoupdate: "true"
creationTimestamp: "2020-08-03T13:43:20Z"
labels:
kubernetes.io/bootstrapping: rbac-defaults
name: cluster-admin
resourceVersion: "40"
selfLink: /apis/rbac.authorization.k8s.io/v1/clusterroles/cluster-admin
uid: 49f5b99c-7cd6-4078-b2f8-ab64051de827
rules:
- apiGroups:
- '*'
resources:
- '*'
verbs:
- '*'
- nonResourceURLs:
- '*'
verbs:
- '*'
对所有组，所有资源，所有url都有权限。具有k8s集群的最高权限。
去运维主机hdss7-200创建相关证书。
[root@hdss7-200 certs]# (umask 077;openssl genrsa -out dashboard.od.com.key 2048)
Generating RSA private key, 2048 bit long modulus
................................................+++
...................................+++
e is 65537 (0x10001)
[root@hdss7-200 certs]# openssl req -new -key dashboard.od.com.key -out dashboard.od.com.csr -subj "/CN=dashboard.od.com/C=CN/ST=BJ/L=Beijing/O=OldboyEdu/OU=ops"
对这个域进行签发，所以cn必须对应相应的域名，而我们之前给K8S签发的时候，对应我们的组件名字，或者集群角色。注意看集群角色是不是集群用户，kube-proxy签发的client证书，就是 system:kube-proxy，就是默认的k8s集群角色。
已经有了一套证书，为什么还要给kube-proxy一套证书？原因就是cn用到了默认集群角色，就不用做rolebinding了。
[root@hdss7-200 certs]# openssl x509 -req -in dashboard.od.com.csr -CA ca.pem -CAkey ca-key.pem -CAcreateserial -out dashboard.od.com.crt -days 3650
Signature ok
subject=/CN=dashboard.od.com/C=CN/ST=BJ/L=Beijing/O=OldboyEdu/OU=ops
Getting CA Private Key
查看一下证书
[root@hdss7-200 certs]# cfssl-certinfo -cert dashboard.od.com.crt
{
"subject": {
"common_name": "dashboard.od.com",
"country": "CN",
"organization": "OldboyEdu",
"organizational_unit": "ops",
"locality": "Beijing",
"province": "BJ",
"names": [
"dashboard.od.com",
"CN",
"BJ",
"Beijing",
"OldboyEdu",
"ops"
]
},
"issuer": {
"common_name": "OldboyEdu",
"country": "CN",
"organization": "old",
"organizational_unit": "ops",
"locality": "beijing",
"province": "beijing",
"names": [
"CN",
"beijing",
"beijing",
"old",
"ops",
"OldboyEdu"
]
},
"serial_number": "16709093817431023485",
"not_before": "2020-08-23T12:39:08Z",
"not_after": "2030-08-21T12:39:08Z",
"sigalg": "SHA256WithRSA",
"authority_key_id": "",
"subject_key_id": "",
"pem": "-----BEGIN CERTIFICATE-----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\nQZh38KGnD/LixSBqcIp1JBVrq9OfO7ue9JQ=\n-----END CERTIFICATE-----\n"
}
然后我们只需要把证书和私钥拷贝到nginx里（7-11主机）
[root@hdss7-11 ~]# cd /etc/nginx/
[root@hdss7-11 nginx]# mkdir certs
[root@hdss7-11 certs]# scp hdss7-200:/opt/certs/dashboard.od.com.crt .
[root@hdss7-11 certs]# scp hdss7-200:/opt/certs/dashboard.od.com.key .
[root@hdss7-11 certs]# ll
total 8
-rw-r--r-- 1 root root 1196 Aug 23 20:43 dashboard.od.com.crt
-rw------- 1 root root 1675 Aug 23 20:44 dashboard.od.com.key
因为我们之前配置了一个nginx反向代理，现在因为签发了证书，需要用到443端口，走https协议，所以我们需要在上一层负载均衡里把证书卸载了，所以这里需要再做一个操作。
[root@hdss7-11 conf.d]# vim dashboard.od.com.conf
注意有个rewrite。
server {
listen 80;
server_name dashboard.od.com;
rewrite ^(.*)$ https://${server_name}$1 permanent;
}
server {
listen 443 ssl;
server_name dashboard.od.com;
ssl_certificate "certs/dashboard.od.com.crt";
ssl_certificate_key "certs/dashboard.od.com.key";
ssl_session_cache shared:SSL:1m;
ssl_session_timeout 10m;
ssl_ciphers HIGH:!aNULL:!MD5;
ssl_prefer_server_ciphers on;
location / {
proxy_pass http://default_backend_traefik;
proxy_set_header Host $http_host;
proxy_set_header x-forwarded-for $proxy_add_x_forwarded_for;
}
}
保存退出，重启nginx
[root@hdss7-11 conf.d]# nginx -t
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful
[root@hdss7-11 conf.d]# nginx -s reload
然后我们访问https://dashboard.od.com域名，浏览器会提示不安全，这是因为我们的证书是自签的，不是权威机构签发的，浏览器不认这个证书，所以会显示不安全。可以看到这个证书是指定域名的证书。
查看证书详情
[root@hdss7-21 ~]# kubectl get secret -n kube-system
[root@hdss7-21 ~]# kubectl describe secret kubernetes-dashboard-admin-token-ghtm2 -n kube-system
Name: kubernetes-dashboard-admin-token-ghtm2
Namespace: kube-system
Labels: <none>
Annotations: kubernetes.io/service-account.name: kubernetes-dashboard-admin
kubernetes.io/service-account.uid: 1ebbb4f2-cfca-494e-a18e-e8164509f45b
Type: kubernetes.io/service-account-token
Data
====
ca.crt: 1346 bytes
namespace: 11 bytes
token: eyJhbGciOiJSUzI1NiIsImtpZCI6IiJ9.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.AG3Zza-JRo8Ezvhep8uMh8qanN8risnwOyTaUe2GSI9228PoBP0kfqzuQ_EzhivVQDzAiOEQX4RXP3LEvyp1kyd3lyDGqIsOYcTlIs-1fc0JV0XOvGd4rPgG8RZ6nNScTli_YzIvmf6nMFOqgsUdeeFS09texvX9RH0Bto-1u6QKmJ2acU6r_XHN1MIxTZ8hgrImgFAgm7ERlDO7_POiKEM-LvhaYaIoY30395RtDdB25hu6MNUN1jNTp5YhMNhluAefc70D8cjy-1uTELOrseTll3q-k0YS0Jrv_N1zMN8nReRS14_zEvnOMJsRqHK9IxA51D9ovlK4wVhCrB22cQ
将token复制到dashboard页面
可以看到已经能够进入设置页面，如果不登陆的话，则无法访问。
更换镜像
自己参考，可做可不做。
[root@hdss7-200 certs]# docker pull hexun/bubernetes-dashboard-amd64:v1.10.1
[root@hdss7-200 certs]# docker images | grep hexun
hexun/kubernetes-dashboard-amd64 v1.10.1 f9aed6605b81 20 months ago 122MB
[root@hdss7-200 certs]# docker tag f9aed6605b81 harbor.od.com/public/dashboard:v1.10.1
[root@hdss7-200 certs]# docker push !$
[root@hdss7-200 certs]# cd /data/k8s-yaml/dashboard
[root@hdss7-200 certs]# vim dp.yaml
# 将如下改成dashboard:v1.10.1
image: harbor.od.com/public/dashboard:v1.8.3
# 注意，下面是7-22主机
[root@hdss7-22 ~]# kubectl apply -f http://k8s-yaml.od.com/dashboard/dp.yaml
会发现，更换到1.10之后，登录界面不能跳过，必须经过身份认证之后才能访问。
一个服务账号一定是对应唯一的服务账号的cigarette，通过describe就可以查看具体的内容，包括token
kubectl describe secret kubernetes-dashboard-admin-token-ghtm2 -n kube-system
回到运维主机上，按照kubernetes官方的配置文件来一次操作，创建（复制）资源配置清单。可以看到这是最小化的权限。
vim rbac-minimal.yaml
apiVersion: v1
kind: ServiceAccount
metadata:
labels:
k8s-app: kubernetes-dashboard
addonmanager.kubernetes.io/mode: Reconcile
name: kubernetes-dashboard
namespace: kube-system
---
kind: Role
apiVersion: rbac.authorization.k8s.io/v1
metadata:
labels:
k8s-app: kubernetes-dashboard
addonmanager.kubernetes.io/mode: Reconcile
name: kubernetes-dashboard-minimal
namespace: kube-system
rules:
# Allow Dashboard to get, update and delete Dashboard exclusive secrets.
- apiGroups: [""]
resources: ["secrets"]
resourceNames: ["kubernetes-dashboard-key-holder", "kubernetes-dashboard-certs"]
verbs: ["get", "update", "delete"]
# Allow Dashboard to get and update 'kubernetes-dashboard-settings' config map.
- apiGroups: [""]
resources: ["configmaps"]
resourceNames: ["kubernetes-dashboard-settings"]
verbs: ["get", "update"]
# Allow Dashboard to get metrics from heapster.
- apiGroups: [""]
resources: ["services"]
resourceNames: ["heapster"]
verbs: ["proxy"]
- apiGroups: [""]
resources: ["services/proxy"]
resourceNames: ["heapster", "http:heapster:", "https:heapster:"]
verbs: ["get"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
name: kubernetes-dashboard-minimal
namespace: kube-system
labels:
k8s-app: kubernetes-dashboard
addonmanager.kubernetes.io/mode: Reconcile
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: Role
name: kubernetes-dashboard-minimal
subjects:
- kind: ServiceAccount
name: kubernetes-dashboard
namespace: kube-system
在7-22节点上
[root@hdss7-22 ~]# kubectl apply -f http://k8s-yaml.od.com/dashboard/rbac-minimal.yaml
serviceaccount/kubernetes-dashboard created
role.rbac.authorization.k8s.io/kubernetes-dashboard-minimal created
rolebinding.rbac.authorization.k8s.io/kubernetes-dashboard-minimal created
在运维主机上，修改dp.yaml如下
serviceAccountName: kubernetes-dashboard
这个serviceAccountName就是上面minimal的用户账户。
再次回到7-22上
[root@hdss7-22 ~]# kubectl apply -f http://k8s-yaml.od.com/dashboard/dp.yaml
deployment.apps/kubernetes-dashboard configured
然后查看新创建的信息
[root@hdss7-22 ~]# kubectl describe secret kubernetes-dashboard-token-hsw9n -n kube-system
Name: kubernetes-dashboard-token-hsw9n
Namespace: kube-system
Labels: <none>
Annotations: kubernetes.io/service-account.name: kubernetes-dashboard
kubernetes.io/service-account.uid: ac5e544d-7527-4e46-a8a7-1a77bb65c3a4
Type: kubernetes.io/service-account-token
Data
====
token: eyJhbGciOiJSUzI1NiIsImtpZCI6IiJ9.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.YrZQz0MMy3ipP1HuKKMCUip9cA0h_c34dL70mz3tq-L0tauL0pxX94OL3VHyY6-6egCSrCVIAiEil4lMPu_hej1erhTuRMgbMALeJKgmwkrINmUb_pg2Io0KzZfxFmAPlU75Hhe1pOuZbh_haeiQKBBcrxLa2Cj-uffEG_F1LKPi3GEr0xj2krtRhn0zcRGb4c8IZ5d1jauXhyTLRiKXD3JzimJdr9kt437lLIfIs45Z21PsAy1fnBIb1arxiInrjomX20ouNo-vjKMN6LjNCeJyugMsmmXYndmhhO9rcp87CYjrzc0NI_roNAsN6Fw5xiHXbD7WFp_B_v_9zaqb_A
ca.crt: 1346 bytes
namespace: 11 bytes
打开dashboard登录页面，输入令牌，进入页面查看。
因此，通过这样的操作，在实际生产中，可以对相应的开发、测试或其他人员赋予不同的权限，比如只能查看。如果想要登录，那么必须先申请token，然后可以根据对应token就可以控制对应的用户权限。
总结一句话就是：K8S就是基于角色来控制权限。
小彩蛋之部署heapster
运维主机7-200上
docker pull quay.io/bitnami/heapster:1.5.4
mkdir heapster
cd heapster
heapster]# vi rbac.yaml
apiVersion: v1
kind: ServiceAccount
metadata:
name: heapster
namespace: kube-system
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
name: heapster
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: system:heapster
subjects:
- kind: ServiceAccount
name: heapster
namespace: kube-system
heapster]# vi dp.yaml
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: heapster
namespace: kube-system
spec:
replicas: 1
template:
metadata:
labels:
task: monitoring
k8s-app: heapster
spec:
serviceAccountName: heapster
containers:
- name: heapster
image: harbor.od.com/public/heapster:v1.5.4
imagePullPolicy: IfNotPresent
command:
- /opt/bitnami/heapster/bin/heapster
- --source=kubernetes:https://kubernetes.default
heapster]# vi svc.yaml
apiVersion: v1
kind: Service
metadata:
labels:
task: monitoring
# For use as a Cluster add-on (https://github.com/kubernetes/kubernetes/tree/master/cluster/addons)
# If you are NOT using this as an addon, you should comment out this line.
kubernetes.io/cluster-service: 'true'
kubernetes.io/name: Heapster
name: heapster
namespace: kube-system
spec:
ports:
- port: 80
targetPort: 8082
selector:
k8s-app: heapster
kubectl apply -f http://k8s-yaml.od.com/dashboard/heapster/rbac.yaml
kubectl apply -f http://k8s-yaml.od.com/dashboard/heapster/dp.yaml
kubectl apply -f http://k8s-yaml.od.com/dashboard/heapster/svc.yaml