screen ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/tty
- login as root
dd if=/dev/zero of=/mnt/docker/zero bs=4096
to fill zero bytes into the free space of the ext4 file system under Docker.qcow4, until the disk is fullrm /mnt/docker/zero
then all the free space of Docker.qcow2 would be filled with zeros- logout, and detach screen
- Finally reduce the the Docker.qcow2 file size,
/Applications/Docker.app/Contents/MacOS/qemu-img convert -O qcow2 Docker.qcow2 Docker2.qcow2
sudo ifconfig lo0 alias 10.254.254.254