d2vm (Docker to Virtual Machine)

Build virtual machine image from Docker images

The project is heavily inspired by the article and the work done by iximiuz on docker-to-linux.

Many thanks to him.

Status: alpha

Supported Environments:

Only Linux is supported.

If you want to run it on OSX or Windows (the last one is totally untested) you can do it using Docker:

alias d2vm='docker run --rm -i -t --privileged -v /var/run/docker.sock:/var/run/docker.sock -v $PWD:/build -w /build linkacloud/d2vm' 

Starting from v0.1.0, d2vm automatically run build and convert commands inside Docker when not running on linux.

Supported VM Linux distributions:

Working and tested:

• Ubuntu (18.04+)
• Debian (stretch+)
• Alpine
• CentOS (8+)

Unsupported:

• RHEL

The program uses the /etc/os-release file to discover the Linux distribution and install the Kernel, if the file is missing, the build cannot succeed.

Obviously, Distroless images are not supported.

Getting started

Clone the git repository:

git clone https://github.com/linka-cloud/d2vm && cd d2vm

Install using the Go tool chain:

go install ./cmd/d2vm
which d2vm

# Should be install in the $GOBIN directory
/go/bin/d2vm

Or use an alias to the docker image:

alias d2vm='docker run --rm -i -t --privileged -v /var/run/docker.sock:/var/run/docker.sock -v $PWD:/build -w /build linkacloud/d2vm'
which d2vm

d2vm: aliased to docker run --rm -i -t --privileged -v /var/run/docker.sock:/var/run/docker.sock -v $PWD:/build -w /build linkacloud/d2vm

Converting an existing Docker Image to VM image:

d2vm convert --help

Convert Docker image to vm image

Usage:
  d2vm convert [docker image] [flags]

Flags:
  -d, --debug             Enable Debug output
  -f, --force             Override output qcow2 image
  -h, --help              help for convert
  -o, --output string     The output image, the extension determine the image format. Supported formats: qcow2 qed raw vdi vhd vmdk (default "disk0.qcow2")
  -p, --password string   The Root user password (default "root")
      --pull              Always pull docker image
  -s, --size string       The output image size (default "10G")

Create an image based on the ubuntu official image:

sudo d2vm convert ubuntu -o ubuntu.qcow2 -p MyP4Ssw0rd

INFO[0000] pulling image ubuntu                         
INFO[0001] inspecting image ubuntu                      
INFO[0002] docker image based on Ubuntu                 
INFO[0002] building kernel enabled image                
INFO[0038] creating root file system archive            
INFO[0040] creating vm image                            
INFO[0040] creating raw image                           
INFO[0040] mounting raw image                           
INFO[0040] creating raw image file system               
INFO[0040] copying rootfs to raw image                  
INFO[0041] setting up rootfs                            
INFO[0041] installing linux kernel                      
INFO[0042] unmounting raw image                         
INFO[0042] writing MBR                                  
INFO[0042] converting to qcow2

You can now run your ubuntu image using the created ubuntu.qcow2 image with qemu:

./qemu.sh ununtu.qcow2

SeaBIOS (version 1.13.0-1ubuntu1.1)


iPXE (http://ipxe.org) 00:03.0 CA00 PCI2.10 PnP PMM+BFF8C920+BFECC920 CA00



Booting from Hard Disk...

SYSLINUX 6.04 EDD 20191223 Copyright (C) 1994-2015 H. Peter Anvin et al
Now booting the kernel from SYSLINUX...
Loading /boot/vmlinuz... ok
Loading /boot/initrd.img...ok
[    0.000000] Linux version 5.4.0-109-generic (buildd@ubuntu) (gcc version 9)
[    0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz ro root=UUID=b117d206-b8
[    0.000000] KERNEL supported cpus:
[    0.000000]   Intel GenuineIntel
[    0.000000]   AMD AuthenticAMD
[    0.000000]   Hygon HygonGenuine
[    0.000000]   Centaur CentaurHauls
[    0.000000]   zhaoxin   Shanghai

...

Welcome to Ubuntu 20.04.4 LTS!

[    3.610631] systemd[1]: Set hostname to <localhost>.
[    3.838984] systemd[1]: Created slice system-getty.slice.
[  OK  ] Created slice system-getty.slice.
[    3.845038] systemd[1]: Created slice system-modprobe.slice.
[  OK  ] Created slice system-modprobe.slice.
[    3.852054] systemd[1]: Created slice system-serial\x2dgetty.slice.
[  OK  ] Created slice system-serial\x2dgetty.slice.

...

Ubuntu 20.04.4 LTS localhost ttyS0

localhost login: 

Log in using the root user and the password configured at build time.

localhost login: root
Password:


Welcome to Ubuntu 20.04.4 LTS (GNU/Linux 5.4.0-109-generic x86_64)

 * Documentation:  https://help.ubuntu.com
 * Management:     https://landscape.canonical.com
 * Support:        https://ubuntu.com/advantage

This system has been minimized by removing packages and content that are
not required on a system that users do not log into.

To restore this content, you can run the 'unminimize' command.

The programs included with the Ubuntu system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.

Ubuntu comes with ABSOLUTELY NO WARRANTY, to the extent permitted by
applicable law.

root@localhost:~#

Type poweroff to shut down the vm.

Building a VM Image from a Dockerfile

The example directory contains very minimalistic examples:

cd examples

ubuntu.Dockerfile :

FROM ubuntu

RUN apt update && apt install -y openssh-server && \
    echo "PermitRootLogin yes" >> /etc/ssh/sshd_config \

When building the vm image, d2vm will create a root password, so there is no need to configure it now.

Build the vm image:

The build command take most of its flags and arguments from the docker build command.

d2vm build --help

Build a vm image from Dockerfile

Usage:
  d2vm build [context directory] [flags]

Flags:
      --build-arg stringArray   Set build-time variables
  -d, --debug                   Enable Debug output
  -f, --file string             Name of the Dockerfile
      --force                   Override output image
  -h, --help                    help for build
  -o, --output string           The output image, the extension determine the image format. Supported formats: qcow2 qed raw vdi vhd vmdk (default "disk0.qcow2")
  -p, --password string         Root user password (default "root")
  -s, --size string             The output image size (default "10G")

sudo d2vm build -p MyP4Ssw0rd -f ubuntu.Dockerfile -o ubuntu.qcow2 .

Or if you want to create a VirtualBox image:

sudo d2vm build -p MyP4Ssw0rd -f ubuntu.Dockerfile -o ubuntu.vdi .

Complete example

A complete example setting up a ZSH workstation is available in the examples/full directory.

Internal Dockerfile templates

You can find the Dockerfiles used to install the Kernel in the templates directory.

TODO / Questions:

• Create service from ENTRYPOINT CMD WORKDIR and ENV instructions ?
• Inject Image ENV variables into .bashrc or other service environment file ?
• Use image layers to create rootfs instead of container ?

Acknowledgments

The run commands are adapted from linuxkit.