Using kubernetes policy with minio.min.io

Question

Pulumi · Accepted Answer

When using MinIO with Kubernetes, you often want to ensure that your MinIO instances are secure and abide by certain network and security policies. Pulumi offers resources to create and manage these policies in a Kubernetes cluster.

For MinIO specifically, you might be interested in:

- **Network Policies**: these Kubernetes resources allow you to control the flow of traffic to and from MinIO Pods. Useful to restrict which clients or services can communicate with your MinIO instances.

- **Pod Security Policies**: these policies control the security specifications a pod must adhere to for it to be accepted into the system, ensuring that MinIO pods run with the appropriate privileges.

- **RBAC Policies**: Role-based access control (RBAC) policies provide granular access controls on who can perform operations on your Kubernetes resources, including MinIO.

Let's write a simple Pulumi TypeScript program where we:
1. Create a `NetworkPolicy` to allow specific inbound and outbound traffic for MinIO.
2. Set a `PodSecurityPolicy` that enforces that MinIO pods must not run as a privileged pod, which is an important security best practice.
3. Bind RBAC permissions to MinIO service accounts to minimize the permissions to exactly what is needed.

Here's what a simple Pulumi program might look like for setting these policies:

```typescript
import * as k8s from '@pulumi/kubernetes';

const name = "minio";

// Define a NetworkPolicy for MinIO.
const minioNetworkPolicy = new k8s.networking.v1.NetworkPolicy(name, {
    metadata: {
        name: "minio-network-policy"
    },
    spec: {
        // Select MinIO pods for this policy.
        podSelector: {
            matchLabels: {
                app: "minio"
            }
        },
        // Define rules for incoming traffic.
        ingress: [{
            from: [{
                // Allow traffic from pods in the same namespace.
                podSelector: {}
            }]
        }],
        // Define rules for outgoing traffic.
        egress: [{
            to: [{
                // Allow traffic to DNS servers.
                namespaceSelector: {},
                podSelector: {
                    matchLabels: {
                        k8sApp: "kube-dns"
                    }
                }
            }]
        }],
        // Apply the policy to incoming and outgoing traffic.
        policyTypes: ["Ingress","Egress"]
    }
}, { provider: /* ...Kubernetes provider... */ });

// Define a PodSecurityPolicy for MinIO.
const minioPodSecurityPolicy = new k8s.policy.v1beta1.PodSecurityPolicy(name, {
    metadata: {
        name: "minio-pod-security-policy"
    },
    spec: {
        // Ensure the pods are not running as privileged.
        privileged: false,
        // Define volumes allowed to be used.
        volumes: ["configMap", "emptyDir", "projected", "secret", "downwardAPI", "persistentVolumeClaim"],
        // Users and groups settings for the pods.
        runAsUser: {
            rule: "MustRunAsNonRoot"
        },
        seLinux: {
            rule: "RunAsAny"
        },
        supplementalGroups: {
            rule: "RunAsAny"
        },
        fsGroup: {
            rule: "RunAsAny"
        }
    }
}, { provider: /* ...Kubernetes provider... */ });

// Define an RBAC ClusterRole for the MinIO server.
const minioClusterRole = new k8s.rbac.v1.ClusterRole(name, {
    metadata: { name: "minio-cluster-role" },
    rules: [
        // List of permissions for MinIO to interact with Kubernetes resources.
        {
            apiGroups: [""],
            resources: ["services", "endpoints", "pods"],
            verbs: ["get", "watch", "list"]
        },
        {
            apiGroups: ["extensions"],
            resources: ["ingresses"],
            verbs: ["get", "watch", "list"]
        },
        // Add more rules as per your security requirements and MinIO needs.
    ],
}, { provider: /* ...Kubernetes provider... */ });

// Outputs
export const networkPolicyName = minioNetworkPolicy.metadata.name;
export const podSecurityPolicyName = minioPodSecurityPolicy.metadata.name;
export const clusterRoleName = minioClusterRole.metadata.name;
```

Replace `/* ...Kubernetes provider... */` with your specific Kubernetes cluster provider configuration if needed; otherwise, Pulumi will use the default provider configuration. The above Pulumi program sets up your MinIO to run with specific security and network configurations which are considered best practices.

Each of the above Pulumi resources is configured to match the needs of a MinIO server.

- The `NetworkPolicy` is scoped to only apply to MinIO's pods.
- The `PodSecurityPolicy` restricts the MinIO pods from running as privileged, which is crucial for minimizing security risks.
- The `ClusterRole` is a sample of how you might limit the Kubernetes API actions that the MinIO pods can perform.

For each resource type, there are many more configuration options you can set. You should adjust them based on your specific security requirements. To learn more about these resources and their configurations, you can refer to the official Pulumi documentation:

- [NetworkPolicy](https://www.pulumi.com/registry/packages/kubernetes/api-docs/networking/v1/networkpolicy/)
- [PodSecurityPolicy](https://www.pulumi.com/registry/packages/kubernetes/api-docs/policy/v1beta1/podsecuritypolicy/)
- [ClusterRole](https://www.pulumi.com/registry/packages/kubernetes/api-docs/rbac/v1/clusterrole/)

Keep in mind that before you can apply these policies, you need to have a working Kubernetes cluster and the appropriate role-based access to create these resources. You'll also need MinIO itself set up within the cluster either through a Helm chart, operator, or manual deployment. These policies serve to protect your existing MinIO deployment.