Use gscfuse on GKE example.
# Download service account keyfile as `key.json` and place project root directory
# Set up environment.
export GCS_BUCKET_NAME={MOUNT_GCS_BUCKET_NAME}
export DOCKER_IMAGE_NAME={BUILD_DOCKER_IMAGE_NAME}
# Use service account
export GOOGLE_APPLICATION_CREDENTIALS=/work/src/test/key.json
# Enable mount
mkdir /mnt/sandbox-hara
gcsfuse -o allow_other sandbox-hara /mnt/sandbox-hara