# Restrict API Access
### 1. 介绍
### 2. Anonymous Access
\\
```
root@master:~/cks/serviceaccount# curl https://localhost:6443
curl: (60) SSL certificate problem: unable to get local issuer certificate
More details here: https://curl.haxx.se/docs/sslcerts.html
curl failed to verify the legitimacy of the server and therefore could not
establish a secure connection to it. To learn more about this situation and
how to fix it, please visit the web page mentioned above.
root@master:~/cks/serviceaccount# curl https://localhost:6443 -k
{
"kind": "Status",
"apiVersion": "v1",
"metadata": {
},
"status": "Failure",
"message": "forbidden: User \"system:anonymous\" cannot get path \"/\"",
"reason": "Forbidden",
"details": {
},
"code": 403
}root@master:~/cks/serviceaccount# vim /etc/kubernetes/manifests/kube-apiserver.yaml
...
- kube-apiserver
- --anonymous-auth=false
- --advertise-address=192.168.211.40
....
root@master:~/cks/serviceaccount# k get pods | grep api
The connection to the server 192.168.211.40:6443 was refused - did you specify the right host or port?
root@master:~/images# k get pods -n kube-system | grep api
kube-apiserver-master 1/1 Running 0 8m3s
root@master:~/images# k get pods -n kube-system | grep api
kube-apiserver-master 1/1 Running 0 3s
```
```
root@master:~/cks/serviceaccount# vim /etc/kubernetes/manifests/kube-apiserver.yaml
...
- kube-apiserver
- --anonymous-auth=true #默认其实为true
- --advertise-address=192.168.211.40
....
root@master:~/cks/serviceaccount# curl https://localhost:6443 -k
{
"kind": "Status",
"apiVersion": "v1",
"metadata": {
},
"status": "Failure",
"message": "forbidden: User \"system:anonymous\" cannot get path \"/\"",
"reason": "Forbidden",
"details": {
},
"code": 403
}
```
### 3. Insecure Access
\
\\
```
root@master:~/cks/serviceaccount# curl https://localhost:6443 -k
{
"kind": "Status",
"apiVersion": "v1",
"metadata": {
},
"status": "Failure",
"message": "forbidden: User \"system:anonymous\" cannot get path \"/\"",
"reason": "Forbidden",
"details": {
},
"code": 403
}
root@master:~# vim /etc/kubernetes/manifests/kube-apiserver.yaml
...
- kube-apiserver
- --advertise-address=192.168.211.40
- --allow-privileged=true
- --authorization-mode=Node,RBAC
- --client-ca-file=/etc/kubernetes/pki/ca.crt
- --enable-admission-plugins=NodeRestriction
- --enable-bootstrap-token-auth=true
- --etcd-cafile=/etc/kubernetes/pki/etcd/ca.crt
- --etcd-certfile=/etc/kubernetes/pki/apiserver-etcd-client.crt
- --etcd-keyfile=/etc/kubernetes/pki/apiserver-etcd-client.key
- --etcd-servers=https://127.0.0.1:2379
- --insecure-port=8080 #0改成8080
.....
root@master:~/cks/serviceaccount# k get pods | grep api
The connection to the server 192.168.211.40:6443 was refused - did you specify the right host or port?
root@master:~/images# k get pods -n kube-system | grep api
kube-apiserver-master 1/1 Running 0 3s
root@master:~# curl http://localhost:8080
```
### 4. Manual API Request
```
root@master:/etc/kubernetes/pki# curl https://192.168.211.40:6443 --cacert ca --cert ca.crt --key ca.key
```
### 5. External Apiserver Access
```
root@master:/etc/kubernetes/pki# k edit svc
....
type: NodePort
....
root@master:/etc/kubernetes/pki# k get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes NodePort 10.96.0.1 443:30300/TCP 19h
root@master:/etc/kubernetes/pki# curl https://192.168.211.40:30300 -l
curl: (60) SSL certificate problem: unable to get local issuer certificate
More details here: https://curl.haxx.se/docs/sslcerts.html
curl failed to verify the legitimacy of the server and therefore could not
establish a secure connection to it. To learn more about this situation and
how to fix it, please visit the web page mentioned above.
root@master:/etc/kubernetes/pki# curl https://192.168.211.40:30300 -k
{
"kind": "Status",
"apiVersion": "v1",
"metadata": {
},
"status": "Failure",
"message": "forbidden: User \"system:anonymous\" cannot get path \"/\"",
"reason": "Forbidden",
"details": {
},
"code": 403
}
```
```
root@master:~/cks/apiserver# k config view --raw >config
root@master:~/cks/apiserver# k --kubeconfig config get ns
NAME STATUS AGE
default Active 19h
kube-node-lease Active 19h
kube-public Active 19h
kube-system Active 19h
root@master:~/cks/apiserver# vim config
.....
server: https://192.168.211.40:30300 #6443改为30300
....
root@master:~/cks/apiserver# k --kubeconfig config get ns
NAME STATUS AGE
default Active 19h
kube-node-lease Active 19h
kube-public Active 19h
kube-system Active 19h
```
### 6. NodeRestriction AdmissionController
\
### 7. Verify NodeRestriction
```
root@master:~/cks/apiserver# vim /etc/kubernetes/manifests/kube-apiserver.yaml
....
- --enable-admission-plugins=NodeRestriction
...
root@master:~/cks/apiserver# k get ns
Error from server (Forbidden): namespaces is forbidden: User "system:node:master" cannot list resource "namespaces" in API group "" at the cluster scope
root@master:~/cks/apiserver# export KUBECONFIG=/etc/kubernetes/kubelet.conf.
root@master:~/cks/apiserver# k label node master cks/test=yes
node/master labeled
root@master:~/cks/apiserver# k label node node1 cks/test=yes
Error from server (Forbidden): nodes "node1" is forbidden: node "master" is not allowed to modify node "node1"
```
---
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