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docker使用OpenPolicyAgent(OPA)进行访问控制

转载 作者：撒哈拉 更新时间：2024-06-05 17:05:21 60 4
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目录
  • 一.系统环境
  • 二.前言
  • 三.Open Policy Agent 简介
  • 四.Rego 语言简介
  • 五.配置基本环境
  • 六.docker安装OPA插件
    • 6.1 安装docker
    • 6.2 docker安装OPA插件
    • 6.3 启用OPA
  • 七.OPA规则
    • 7.1 允许docker所有操作
    • 7.2 禁止docker所有操作
    • 7.3 禁止创建允许所有系统调用的docker容器
    • 7.4 根据Authz-User判断用户是否具有创建pod权限
  • 八.总结

一.系统环境

本文主要基于Docker version 20.10.16和Linux操作系统Ubuntu 18.04.

服务器版本 docker软件版本 CPU架构
Ubuntu 18.04.5 LTS Docker version 20.10.16 x86_64

二.前言

在容器化技术中，Docker 已经成为广泛使用的工具。然而，随着容器数量的增加，确保容器之间的安全隔离变得越来越重要。Docker 提供了各种安全特性，但有时我们可能需要更细粒度的访问控制策略。Open Policy Agent（OPA）是一个开源的通用策略引擎，可以与 Docker 集成，以实现更灵活的访问控制。本文将介绍如何在 Docker 中使用 OPA 进行访问控制.

三.Open Policy Agent 简介

OPA 是一个开源的通用策略引擎，可以评估策略并做出决策。OPA 可以应用于各种场景，例如网络安全、访问控制、数据保护等。在 Docker 环境中，OPA 可以用于评估容器之间的访问请求，并根据预定义的策略做出决策，Open Policy Agent（OPA）的官网为：https://www.openpolicyagent.org/.

虽然 Docker 提供了各种安全特性，例如网络隔离、资源限制等，但有时我们可能需要更细粒度的访问控制策略。例如，我们可能希望限制某些容器对特定资源的访问，或根据容器的标签和属性来控制访问权限。这就是 OPA 发挥作用的地方。通过集成 OPA，我们可以实现更灵活、可扩展的访问控制策略.

一般情况下，我们使用docker执行docker命令是没有什么限制的，安装OPA插件，并启用OPA，创建了相关的OPA规则之后，使用docker执行docker命令，需要先访问OPA规则，如果OPA规则表示你有权限执行命令，则docker命令执行成功，否则执行失败.

四.Rego 语言简介

Rego 是一种用于编写策略的语言，是 OPA 的核心组成部分。它是一种声明性语言，可以描述复杂的数据结构和逻辑。Rego 语法简洁，易于理解，使得编写策略变得更加简单。在本文中，我们将使用 Rego 语言编写访问控制策略.

五.配置基本环境

本次使用一台新的Ubuntu机器（使用别的系统也行），下面给新机器配置基本环境.

查看Ubuntu系统版本.

root@localhost:~# lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 18.04.5 LTS
Release:	18.04
Codename:	bionic

首先设置主机名.

root@localhost:~# vim /etc/hostname 

root@localhost:~# cat /etc/hostname
ubuntuk8sclient

配置节点静态IP地址（可选）。如果您对Ubuntu系统不熟悉，请查看博客《centos系统和Ubuntu系统命令区别以及常见操作》.

root@localhost:~# vim /etc/netplan/01-netcfg.yaml

root@localhost:~# cat /etc/netplan/01-netcfg.yaml
network:
  version: 2
  renderer: networkd
  ethernets:
    ens32:
      dhcp4: no
      addresses: [192.168.110.139/24]
      gateway4: 192.168.110.2
      nameservers:
        addresses: [192.168.110.2,114.114.114.114]

使网卡配置生效.

root@localhost:~# netplan apply

测试机器是否可以访问网络.

root@localhost:~# ping www.baidu.com
PING www.baidu.com (14.215.177.39) 56(84) bytes of data.
64 bytes from www.baidu.com (14.215.177.39): icmp_seq=1 ttl=128 time=54.3 ms
64 bytes from www.baidu.com (14.215.177.39): icmp_seq=2 ttl=128 time=44.6 ms
64 bytes from www.baidu.com (14.215.177.39): icmp_seq=3 ttl=128 time=41.3 ms
64 bytes from www.baidu.com (14.215.177.39): icmp_seq=4 ttl=128 time=37.0 ms
64 bytes from www.baidu.com (14.215.177.39): icmp_seq=5 ttl=128 time=43.7 ms
^C
--- www.baidu.com ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4007ms
rtt min/avg/max/mdev = 37.072/44.239/54.332/5.695 ms

查看IP.

root@localhost:~# ifconfig
ens32: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.110.139  netmask 255.255.255.0  broadcast 192.168.110.255
        inet6 fe80::20c:29ff:fe97:b27b  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:97:b2:7b  txqueuelen 1000  (Ethernet)
        RX packets 20269  bytes 22473377 (22.4 MB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 7755  bytes 544420 (544.4 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 1650  bytes 119324 (119.3 KB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 1650  bytes 119324 (119.3 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

配置IP和主机名映射.

root@localhost:~# vim /etc/hosts

root@localhost:~# cat /etc/hosts
127.0.0.1	localhost
127.0.1.1	tom
192.168.110.139 ubuntuk8sclient

# The following lines are desirable for IPv6 capable hosts
::1     localhost ip6-localhost ip6-loopback
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

配置软件源.

root@ubuntuk8sclient:~# vim /etc/apt/sources.list

 #软件源如下，最后三行是k8s源
root@ubuntuk8sclient:~# cat /etc/apt/sources.list
deb http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse

deb http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse

deb http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse

deb http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse

deb http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse

deb https://mirrors.aliyun.com/kubernetes/apt/ kubernetes-xenial main
deb [arch=amd64] https://mirrors.aliyun.com/docker-ce/linux/ubuntu bionic stable
# deb-src [arch=amd64] https://mirrors.aliyun.com/docker-ce/linux/ubuntu bionic stable

apt-key.gpg是k8s的deb源公钥，加载k8s的deb源公钥命令为：apt-key add apt-key.gpg.

下载并加载k8s的deb源公钥命令为：curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add - ; apt-get update，但是谷歌的网址访问不了，我们直接去网上下载apt-key.gpg文件.

root@ubuntuk8sclient:~# ls
apt-key.gpg

加载k8s的deb源公钥.

root@ubuntuk8sclient:~# cat apt-key.gpg | apt-key add -
OK

更新软件源.

root@ubuntuk8sclient:~# apt-get update

关闭防火墙.

root@ubuntuk8sclient:~# ufw disable
Firewall stopped and disabled on system startup

Linux swapoff命令用于关闭系统交换分区(swap area)。如果不关闭swap，就会在kubeadm初始化Kubernetes的时候报错：“[ERROR Swap]: running with swap on is not supported. Please disable swap”.

root@ubuntuk8sclient:~# swapoff -a ;sed -i '/swap/d' /etc/fstab

root@ubuntuk8sclient:~# cat /etc/fstab
# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
/dev/mapper/tom--vg-root /               ext4    errors=remount-ro 0       1

此时基本环境就配置完毕了.

六.docker安装OPA插件

6.1 安装docker

安装docker.

root@ubuntuk8sclient:~# apt-get install docker-ce -y

root@ubuntuk8sclient:~# which docker
/usr/bin/docker

查看docker安装包.

root@ubuntuk8sclient:~# dpkg -l | grep docker
ii  docker-ce                              5:20.10.16~3-0~ubuntu-bionic                    amd64        Docker: the open-source application container engine
ii  docker-ce-cli                          5:20.10.16~3-0~ubuntu-bionic                    amd64        Docker CLI: the open-source application container engine
ii  docker-ce-rootless-extras              5:20.10.16~3-0~ubuntu-bionic                    amd64        Rootless support for Docker.
ii  docker-scan-plugin                     0.17.0~ubuntu-bionic                            amd64        Docker scan cli plugin.

设置docker开机自启动并现在启动docker.

root@ubuntuk8sclient:~# systemctl enable docker --now
Synchronizing state of docker.service with SysV service script with /lib/systemd/systemd-sysv-install.
Executing: /lib/systemd/systemd-sysv-install enable docker

查看docker状态.

root@ubuntuk8sclient:~# systemctl status docker
● docker.service - Docker Application Container Engine
   Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: enabled)
   Active: active (running) since Fri 2022-05-27 17:39:41 CST; 2min 27s ago
     Docs: https://docs.docker.com
 Main PID: 2574 (dockerd)
    Tasks: 8
   CGroup: /system.slice/docker.service
           └─2574 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock

May 27 17:39:37 ubuntuk8sclient dockerd[2574]: time="2022-05-27T17:39:37.223612352+08:00" level=info msg="ClientConn switching balancer to \"pick_first\"" module=grpc
May 27 17:39:37 ubuntuk8sclient dockerd[2574]: time="2022-05-27T17:39:37.512415652+08:00" level=warning msg="Your kernel does not support swap memory limit"
May 27 17:39:37 ubuntuk8sclient dockerd[2574]: time="2022-05-27T17:39:37.512456896+08:00" level=warning msg="Your kernel does not support CPU realtime scheduler"
May 27 17:39:37 ubuntuk8sclient dockerd[2574]: time="2022-05-27T17:39:37.512593678+08:00" level=info msg="Loading containers: start."
May 27 17:39:40 ubuntuk8sclient dockerd[2574]: time="2022-05-27T17:39:40.261550128+08:00" level=info msg="Default bridge (docker0) is assigned with an IP address 172.17.0.0/16. Daemon option --bip can be used t

查看docker版本.

root@ubuntuk8sclient:~# docker --version
Docker version 20.10.16, build aa7e414

配置docker阿里云镜像加速器.

root@ubuntuk8sclient:~# vim /etc/docker/daemon.json

root@ubuntuk8sclient:~# cat /etc/docker/daemon.json
{
        "registry-mirrors": ["https://frz7i079.mirror.aliyuncs.com"]
}

重新加载配置文件，重启docker.

root@ubuntuk8sclient:~# systemctl daemon-reload ; systemctl restart docker

root@ubuntuk8sclient:~# systemctl status docker
● docker.service - Docker Application Container Engine
   Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: enabled)
   Active: active (running) since Fri 2022-05-27 17:45:41 CST; 5s ago
     Docs: https://docs.docker.com
 Main PID: 4330 (dockerd)
    Tasks: 8
   CGroup: /system.slice/docker.service
           └─4330 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock

下载一个nginx镜像.

root@ubuntuk8sclient:~# docker pull nginx

root@ubuntuk8sclient:~# docker images
REPOSITORY   TAG       IMAGE ID       CREATED        SIZE
nginx        latest    605c77e624dd   4 months ago   141MB

现在创建docker容器是没有限制的，可以自由创建和删除。关于docker容器的详细操作，请查看博客《一文搞懂docker容器基础：docker镜像管理，docker容器管理》.

#使用nginx镜像创建容器
root@ubuntuk8sclient:~# docker run -dit --name=nginxweb --restart=always nginx
16d5558fbe8d8956d61714326bea89e5a86424503c323dab03e729927f71fb5b

#查看容器
root@ubuntuk8sclient:~# docker ps 
CONTAINER ID   IMAGE     COMMAND                  CREATED          STATUS          PORTS     NAMES
16d5558fbe8d   nginx     "/docker-entrypoint.…"   16 seconds ago   Up 13 seconds   80/tcp    nginxweb

#删除容器
root@ubuntuk8sclient:~# docker rm -f nginxweb 
nginxweb

root@ubuntuk8sclient:~# docker ps 
CONTAINER ID   IMAGE     COMMAND   CREATED   STATUS    PORTS     NAMES

6.2 docker安装OPA插件

在安装OPA插件之前，先介绍下docker插件常用命令，Docker插件是增强Docker引擎功能的进程外扩展。docker plugin命令用于管理插件.

docker plugin create     #从rootfs和配置创建一个插件。插件数据目录必须包含config.json和rootfs目录。
docker plugin disable    #禁用插件
docker plugin enable     #启用插件
docker plugin inspect    #显示一个或多个插件的详细信息
docker plugin install    #安装一个插件
docker plugin ls         #列出所有插件
docker plugin push       #将插件推送到注册表
docker plugin rm         #删除一个或多个插件
docker plugin set        #更改插件的设置
docker plugin upgrade    #升级现有插件

/etc/docker/policies用来存放opa规则.

root@ubuntuk8sclient:~# mkdir -p /etc/docker/policies

root@ubuntuk8sclient:~# ls /etc/docker/
daemon.json  key.json  policies

查看docker插件，现在没有任何插件.

root@ubuntuk8sclient:~# docker plugin list
ID        NAME      DESCRIPTION   ENABLED

下载好的docker插件会放在/var/lib/docker/plugins/目录.

root@ubuntuk8sclient:~# ls /var/lib/docker/plugins/
storage  tmp

安装OPA插件.

root@ubuntuk8sclient:~# docker plugin install openpolicyagent/opa-docker-authz-v2:0.8 opa-args="-policy-file /opa/policies/authz.rego"
Plugin "openpolicyagent/opa-docker-authz-v2:0.8" is requesting the following privileges:
 - network: [host]
 - mount: [/etc/docker]
Do you grant the above permissions? [y/N] y
0.8: Pulling from openpolicyagent/opa-docker-authz-v2
Digest: sha256:2fbbef244625e57f2beb7967a1b21c43ce5c7e6ec823fb1c35fe1b327ae3a1c4
cb581d64bd7f: Complete 
Installed plugin openpolicyagent/opa-docker-authz-v2:0.8

现在OPA插件就安装好了.

root@ubuntuk8sclient:~# docker plugin list
ID             NAME                                      DESCRIPTION                                     ENABLED
20b4566c59fc   openpolicyagent/opa-docker-authz-v2:0.8   A policy-enabled authorization plugin for Do…   true

docker OPA插件安装好之后，在/var/lib/docker/plugins/目录下.

root@ubuntuk8sclient:~# ls /var/lib/docker/plugins/
20b4566c59fc71641bda21da72d75299405e9c5c8b4cc859f6ab636f4f19cc52  storage  tmp

查看OPA属性.

注意："-policy-file /opa/policies/authz.rego"里的/opa不是操作系统里的/opa目录，而是/etc/docker/下的opa.

docker plugin inspect 20b4566c59fc显示的Mounts选项可以看出，/etc/docker目录挂载到/opa目录了，所以访问容器/opa目录就相当于访问宿主机/etc/docker目录.

root@ubuntuk8sclient:~# docker plugin inspect 20b4566c59fc
[
    {
        "Config": {
            ......
            #注意："-policy-file /opa/policies/authz.rego"里的/opa不是操作系统里的/opa目录，而是/etc/docker/下的opa，
            #docker plugin inspect 20b4566c59fc显示的Mounts选项可以看出，/etc/docker目录挂载到/opa目录了，所以访问容器/opa目录就相当于访问宿主机/etc/docker目录
            "Mounts": [
                {
                    "Description": "",
                    "Destination": "/opa",
                    "Name": "policy",
                    "Options": [
                        "bind",
                        "ro"
                    ],
                    "Settable": [
                        "source"
                    ],
                    "Source": "/etc/docker",
                    "Type": "none"
                }
            ],
           ......
            "Mounts": [
                {
                    "Description": "",
                    "Destination": "/opa",
                    "Name": "policy",
                    "Options": [
                        "bind",
                        "ro"
                    ],
                    "Settable": [
                        "source"
                    ],
                    "Source": "/etc/docker",
                    "Type": "none"
                }
            ]
        }
    }
]

6.3 启用OPA

安装OPA插件之后需要启用OPA，"authorization-plugins": ["openpolicyagent/opa-docker-authz-v2:0.8"]指定OPA插件.

root@ubuntuk8sclient:~# cd /etc/docker/policies/

root@ubuntuk8sclient:/etc/docker/policies# vim /etc/docker/daemon.json 

root@ubuntuk8sclient:/etc/docker/policies# cat /etc/docker/daemon.json
{
        "registry-mirrors": ["https://frz7i079.mirror.aliyuncs.com"],
        "authorization-plugins": ["openpolicyagent/opa-docker-authz-v2:0.8"]
}

重启docker，这样就启用了OPA.

root@ubuntuk8sclient:/etc/docker/policies# systemctl daemon-reload ; systemctl restart docker

七.OPA规则

7.1 允许docker所有操作

下面开始编写OPA规则，OPA规则使用rego语言编写，allow := true 表示允许所有操作.

root@ubuntuk8sclient:/etc/docker/policies# vim authz.rego

root@ubuntuk8sclient:/etc/docker/policies# cat /etc/docker/policies/authz.rego 
package docker.authz
allow := true

可以查看镜像及其所有操作.

root@ubuntuk8sclient:/etc/docker/policies# docker images
REPOSITORY   TAG       IMAGE ID       CREATED        SIZE
nginx        latest    605c77e624dd   5 months ago   141MB

7.2 禁止docker所有操作

编辑OPA规则，allow := false表示禁止所有操作.

root@ubuntuk8sclient:/etc/docker/policies# vim /etc/docker/policies/authz.rego

root@ubuntuk8sclient:/etc/docker/policies# cat /etc/docker/policies/authz.rego
package docker.authz
allow := false

现在docker的所有操作都执行不了了.

root@ubuntuk8sclient:/etc/docker/policies# docker images
Error response from daemon: authorization denied by plugin openpolicyagent/opa-docker-authz-v2:0.8: request rejected by administrative policy

root@ubuntuk8sclient:/etc/docker/policies# docker ps
Error response from daemon: authorization denied by plugin openpolicyagent/opa-docker-authz-v2:0.8: request rejected by administrative policy

7.3 禁止创建允许所有系统调用的docker容器

OPA规则设置为允许所有docker请求.

root@ubuntuk8sclient:/etc/docker/policies# vim /etc/docker/policies/authz.rego

root@ubuntuk8sclient:/etc/docker/policies# cat /etc/docker/policies/authz.rego
package docker.authz
#allow := true允许所有docker请求
allow := true

使用nginx镜像创建一个允许所有系统调用的容器，--security-opt seccomp:unconfined表示允许所有系统调用。关于系统调用的详细操作，请查看博客《在kubernetes里使用seccomp限制容器的系统调用》.

root@ubuntuk8sclient:/etc/docker/policies# docker run -dit --restart=always --name=nginxweb --security-opt seccomp:unconfined nginx
033a0e8e38c56a00400eeefe5424f55ca953e320e6d668831f4cdc580837294f

root@ubuntuk8sclient:/etc/docker/policies# docker ps 
CONTAINER ID   IMAGE     COMMAND                  CREATED         STATUS         PORTS     NAMES
033a0e8e38c5   nginx     "/docker-entrypoint.…"   5 seconds ago   Up 4 seconds   80/tcp    nginxweb

查看nginxweb的属性，在docker inspect nginxweb的输出中，可以看到HostConfig.SecurityOpt[seccomp:unconfined]，创建docker指定的选项都可以在docker inspect里看到.

root@ubuntuk8sclient:/etc/docker/policies# docker inspect nginxweb
[
    {
        ......
            "OomScoreAdj": 0,
            "PidMode": "",
            "Privileged": false,
            "PublishAllPorts": false,
            "ReadonlyRootfs": false,
            "SecurityOpt": [
                "seccomp:unconfined"
            ],
            "UTSMode": "",
              ......
                    "GlobalIPv6PrefixLen": 0,
                    "MacAddress": "02:42:ac:11:00:02",
                    "DriverOpts": null
                }
            }
        }
    }
]

删除docker容器.

root@ubuntuk8sclient:/etc/docker/policies# docker ps
CONTAINER ID   IMAGE     COMMAND                  CREATED         STATUS         PORTS     NAMES
033a0e8e38c5   nginx     "/docker-entrypoint.…"   6 minutes ago   Up 6 minutes   80/tcp    nginxweb

root@ubuntuk8sclient:/etc/docker/policies# docker rm -f nginxweb
nginxweb

root@ubuntuk8sclient:/etc/docker/policies# docker ps
CONTAINER ID   IMAGE     COMMAND   CREATED   STATUS    PORTS     NAMES

修改OPA规则，现在OPA规则HostConfig.SecurityOpt[_] == "seccomp:unconfined"都deny了，所以docker指定--security-opt seccomp:unconfined选项时，就运行不了了.

root@ubuntuk8sclient:/etc/docker/policies# vim /etc/docker/policies/authz.rego 

root@ubuntuk8sclient:/etc/docker/policies# cat /etc/docker/policies/authz.rego
package docker.authz
#默认拒绝
default allow = false

#allow这里可以写all,表示允许所有
#表示除了拒绝之外的那些都允许
allow {
    not deny
}

#表示拒绝seccomp_unconfined
deny {
    seccomp_unconfined
}

#seccomp_unconfined的详细信息
seccomp_unconfined {
    # This expression asserts that the string on the right-hand side is equal
    # to an element in the array SecurityOpt referenced on the left-hand side.
    input.Body.HostConfig.SecurityOpt[_] == "seccomp:unconfined"
}

现在允许所有系统调用的docker容器就创建不了了，备注：--security-opt seccomp:unconfined 表示允许所有的系统调用.

root@ubuntuk8sclient:/etc/docker/policies# docker run -dit --restart=always --name=nginxweb --security-opt seccomp:unconfined nginx
docker: Error response from daemon: authorization denied by plugin openpolicyagent/opa-docker-authz-v2:0.8: request rejected by administrative policy.
See 'docker run --help'.

创建普通的容器就可以成功.

root@ubuntuk8sclient:/etc/docker/policies# docker run -dit --restart=always --name=nginxweb nginx
304948d90988bbba4b7c0503980c60dfd636f2dccd33e90f2158fc93b6c7c63c

root@ubuntuk8sclient:/etc/docker/policies# docker ps
CONTAINER ID   IMAGE     COMMAND                  CREATED         STATUS         PORTS     NAMES
304948d90988   nginx     "/docker-entrypoint.…"   4 seconds ago   Up 3 seconds   80/tcp    nginxweb

root@ubuntuk8sclient:/etc/docker/policies# docker rm -f nginxweb 
nginxweb

root@ubuntuk8sclient:/etc/docker/policies# docker ps
CONTAINER ID   IMAGE     COMMAND   CREATED   STATUS    PORTS     NAMES

7.4 根据Authz-User判断用户是否具有创建pod权限

使用harbor搭建一个镜像仓库，镜像仓库里新建项目，可以设置是否允许匿名用户pull镜像，如果设置了不允许匿名用户pull镜像，则客户端必须docker login登录才行，否则docker pull拉取不了镜像，docker push的话必须登录，不能匿名用户push镜像到镜像仓库。关于harbor镜像仓库的详细操作，请查看博客《搭建docker镜像仓库(二)：使用harbor搭建本地镜像仓库》.

当我们使用docker login登录harbor之后，Docker 会将 token 存储在 ~/.docker/config.json 文件中，从而作为拉取私有镜像的凭证.

root@ubuntuk8sclient:~# mkdir ~/.docker

root@ubuntuk8sclient:/etc/docker/policies# cat >~/.docker/config.json <<EOF
> {
>     "HttpHeaders": {
>         "Authz-User": "alice"
>     }
> }
> EOF

config.json表示现在是alice登录拉取私有镜像的.

root@ubuntuk8sclient:~# cat ~/.docker/config.json 
{
    "HttpHeaders": {
        "Authz-User": "alice"
    }
}

编辑OPA规则，如果用户被授予读写权限，则允许创建容器.

root@ubuntuk8sclient:~# vim /etc/docker/policies/authz.rego 

root@ubuntuk8sclient:~# cat /etc/docker/policies/authz.rego
package docker.authz
#默认拒绝
default allow = false

# allow if the user is granted read/write access.
#如果用户被授予读写权限，则允许
allow {
    user_id := input.Headers["Authz-User"]
    user := users[user_id]
    not user.readOnly
}

# allow if the user is granted read-only access and the request is a GET.
#如果用户被授予只读访问权限并且请求是GET，则允许
allow {
    user_id := input.Headers["Authz-User"]
    users[user_id].readOnly
    input.Method == "GET"
}

# users defines permissions for the user. In this case, we define a single
# attribute 'readOnly' that controls the kinds of commands the user can run.
#bob用户只读，alice用户读写
users := {
    "bob": {"readOnly": true},
    "alice": {"readOnly": false},
}

现在是"Authz-User": "alice"，alice具有读写权限，成功创建容器.

root@ubuntuk8sclient:~# docker run -dit --restart=always --name=nginxweb nginx
e6aeb23a91a55fbad3fd5db9d0ac87ade1be13e990d17e6a29e9f0ca83cb5424

root@ubuntuk8sclient:~# docker ps 
CONTAINER ID   IMAGE     COMMAND                  CREATED         STATUS         PORTS     NAMES
e6aeb23a91a5   nginx     "/docker-entrypoint.…"   4 seconds ago   Up 3 seconds   80/tcp    nginxweb

root@ubuntuk8sclient:~# docker rm -f nginxweb 
nginxweb

表示现在是bob登录拉取私有镜像的.

root@ubuntuk8sclient:~# vim ~/.docker/config.json

root@ubuntuk8sclient:~# cat ~/.docker/config.json
{
    "HttpHeaders": {
        "Authz-User": "bob"
    }
}

bob只有只读权限，并且只能执行get，创建容器失败.

root@ubuntuk8sclient:~# docker run -dit --restart=always --name=nginxweb nginx
docker: Error response from daemon: authorization denied by plugin openpolicyagent/opa-docker-authz-v2:0.8: request rejected by administrative policy.
See 'docker run --help'.

八.总结

本文介绍了如何使用 Open Policy Agent（OPA）为 Docker 容器提供访问控制。通过使用 OPA，我们可以轻松地实现细粒度的访问控制策略，从而提高 Docker 容器的安全性.

最后此篇关于docker使用OpenPolicyAgent(OPA)进行访问控制的文章就讲到这里了,如果你想了解更多关于docker使用OpenPolicyAgent(OPA)进行访问控制的内容请搜索CFSDN的文章或继续浏览相关文章，希望大家以后支持我的博客！ 。

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