Automating Security Best Practices With Gatekeeper Policies

Introduction

In this guide, we will automate security best practices using Gatekeeper policies with Pulumi. Gatekeeper is a customizable policy enforcement tool for Kubernetes that helps ensure compliance with security policies. By integrating Gatekeeper with Pulumi, we can automate the deployment and management of these policies.

Step-by-Step Explanation

Step 1: Install Pulumi and Configure Your Environment

1. Install Pulumi CLI from Pulumi’s installation guide.
2. Configure Pulumi to use your preferred cloud provider (AWS in this case) by setting up your AWS credentials.

Step 2: Create a New Pulumi Project

1. Create a new directory for your Pulumi project and navigate into it.

   mkdir pulumi-gatekeeper
   cd pulumi-gatekeeper
   

2. Initialize a new Pulumi project.

   pulumi new aws-typescript
   

Step 3: Install Required Packages

1. Install the Pulumi Kubernetes package.

   npm install @pulumi/kubernetes
   

2. Install the Gatekeeper package.

   npm install @pulumi/kubernetes-opa
   

Step 4: Define Gatekeeper Policies

1. Create a new file named gatekeeper.ts and define your Gatekeeper policies.

   import * as pulumi from "@pulumi/pulumi";
   import * as k8s from "@pulumi/kubernetes";
   import * as gatekeeper from "@pulumi/kubernetes-opa";
   
   const ns = new k8s.core.v1.Namespace("gatekeeper", {
       metadata: { name: "gatekeeper" },
   });
   
   const template = new gatekeeper.v1.ConstraintTemplate("k8srequiredlabels", {
       metadata: { name: "k8srequiredlabels" },
       spec: {
           crd: {
               spec: {
                   names: {
                       kind: "K8sRequiredLabels",
                   },
                   validation: {
                       openAPIV3Schema: {
                           properties: {
                               labels: { type: "array", items: { type: "string" } },
                           },
                       },
                   },
               },
           },
           targets: [{ target: "admission.k8s.gatekeeper.sh" }],
       },
   });
   
   const constraint = new gatekeeper.v1.Constraint("must-have-gk", {
       metadata: { name: "must-have-gk" },
       spec: {
           enforcementAction: "deny",
           match: {
               kinds: [{ apiGroups: [""], kinds: ["Pod"] }],
           },
           parameters: {
               labels: ["gatekeeper"],
           },
       },
   });
   

Step 5: Deploy Your Project

1. Deploy your Gatekeeper policies using Pulumi.

   pulumi up
   

2. Confirm the deployment and verify that the policies are enforced in your Kubernetes cluster.

Summary

By following these steps, you have automated the deployment of security best practices using Gatekeeper policies with Pulumi. This integration ensures that your Kubernetes clusters remain compliant with your security policies, providing a robust and automated solution for policy enforcement.

Full Code Example

import * as pulumi from "@pulumi/pulumi";
import * as k8s from "@pulumi/kubernetes";

const ns = new k8s.core.v1.Namespace("gatekeeper", {
    metadata: { name: "gatekeeper" },
});

const crd = new k8s.apiextensions.v1.CustomResourceDefinition("k8srequiredlabels", {
    metadata: { name: "k8srequiredlabels" },
    spec: {
        group: "constraints.gatekeeper.sh",
        versions: [{
            name: "v1beta1",
            served: true,
            storage: true,
            schema: {
                openAPIV3Schema: {
                    type: "object",
                    properties: {
                        spec: {
                            type: "object",
                            properties: {
                                enforcementAction: { type: "string" },
                                match: {
                                    type: "object",
                                    properties: {
                                        kinds: {
                                            type: "array",
                                            items: {
                                                type: "object",
                                                properties: {
                                                    apiGroups: {
                                                        type: "array",
                                                        items: { type: "string" },
                                                    },
                                                    kinds: {
                                                        type: "array",
                                                        items: { type: "string" },
                                                    },
                                                },
                                            },
                                        },
                                    },
                                },
                                parameters: {
                                    type: "object",
                                    properties: {
                                        labels: {
                                            type: "array",
                                            items: { type: "string" },
                                        },
                                    },
                                },
                            },
                        },
                    },
                },
            },
        }],
        scope: "Namespaced",
        names: {
            plural: "k8srequiredlabels",
            singular: "k8srequiredlabel",
            kind: "K8sRequiredLabels",
            shortNames: ["krl"],
        },
    },
});

const webhook = new k8s.admissionregistration.v1.ValidatingWebhookConfiguration("gatekeeper-webhook", {
    metadata: { name: "gatekeeper-webhook" },
    webhooks: [{
        name: "validation.gatekeeper.sh",
        clientConfig: {
            service: {
                name: "gatekeeper-webhook-service",
                namespace: ns.metadata.name,
                path: "/v1/admit",
            },
            caBundle: "<ca-bundle>"
        },
        rules: [{
            operations: ["CREATE", "UPDATE"],
            apiGroups: [""],
            apiVersions: ["v1"],
            resources: ["pods"],
        }],
        failurePolicy: "Fail",
        sideEffects: "None",
        admissionReviewVersions: ["v1"],
    }],
});

export const namespaceName = ns.metadata.name;
export const crdName = crd.metadata.name;
export const webhookName = webhook.metadata.name;