How do I restrict container filesystem access to read-only?

In this guide, we will demonstrate how to restrict filesystem access to read-only for containers in a Kubernetes Pod using Pulumi. This is an important security measure to ensure that the containers cannot modify the filesystem, thereby preventing potential security breaches.

We will create a Kubernetes Pod with a container that has its filesystem set to read-only. This is achieved by setting the readOnlyRootFilesystem security context to true.

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

// Define the Kubernetes Pod
const pod = new k8s.core.v1.Pod("readonly-pod", {
    metadata: {
        name: "readonly-pod",
    },
    spec: {
        containers: [{
            name: "nginx",
            image: "nginx:latest",
            securityContext: {
                readOnlyRootFilesystem: true, // Set the root filesystem to read-only
            },
        }],
    },
});

// Export the Pod name
export const podName = pod.metadata.name;

Key Points

• Security Context: The securityContext field is used to specify security settings for the container.
• Read-Only Filesystem: Setting readOnlyRootFilesystem to true ensures that the container’s root filesystem is read-only.
• Kubernetes Pod: We define a Kubernetes Pod with a single container running the Nginx image.

Conclusion

In this guide, we demonstrated how to restrict filesystem access to read-only for a container in a Kubernetes Pod using Pulumi. This security measure helps in preventing unauthorized modifications to the container’s filesystem.