Is it possible to run gcsfuse without privileged mode inside GCP kubernetes?

Following this guide,I am trying to run gcsfuse inside a pod in GKE. Below is the deployment manifest that I am using:

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: gcsfuse-test
spec:
  replicas: 1
  template:
    metadata:
      labels:
        app: gcsfuse-test
    spec:
      containers:
        - name: gcsfuse-test
          image: gcr.io/project123/gcs-test-fuse:latest
          securityContext:
            privileged: true
            capabilities:
              add:
                - SYS_ADMIN
          lifecycle:
            postStart:
              exec:
                command: ["mkdir", "/mnt"]
                command: ["gcsfuse", "-o", "nonempty", "cloudsql-p8p", "/mnt"]
            preStop:
              exec:
                command: ["fusermount", "-u", "/mnt"]

However, I would like to run gcsfuse without the privileged mode inside my GKE Cluster. I think (because of questions like these on SO) it is possible to run the docker image with certain flags and there will be no need to run it in privileged mode.

Is there any way in GKE to run gcsfuse without running the container in privileged mode?

Privileged mode means you have all the capabilities enabled, see https://stackoverflow.com/a/36441605. So adding CAP_SYS_ADMIN looks redundant here in your example.

You can either give all the privileges or do something more fine-grained by mounting /dev/fuse and giving only SYS_ADMIN capability (which remains an important permission).

I think we can rephrase the question as : Can we run GCSFuse without the capability SYS_ADMIN ?

Actually it does not look feasible, you can find the related docker issue here : https://github.com/docker/for-linux/issues/321.

For most of projects it won't be a hard no-go. You may want to act in regard of your threat model and decide whether or not it may be a security risk for your production.