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d2vm/README.md
Adphi cf26472bdc
add keep-cache option to preserve intermediate docker images
Signed-off-by: Adphi <philippe.adrien.nousse@gmail.com>
2023-02-28 17:45:33 +01:00

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# d2vm (Docker to Virtual Machine)
[![Language: Go](https://img.shields.io/badge/lang-Go-6ad7e5.svg?style=flat-square&logo=go)](https://golang.org/)
[![Go Reference](https://pkg.go.dev/badge/go.linka.cloud/d2vm.svg)](https://pkg.go.dev/go.linka.cloud/d2vm)
[![Chat](https://img.shields.io/badge/chat-matrix-blue.svg?style=flat-square&logo=matrix)](https://matrix.to/#/#d2vm:linka.cloud)
*Build virtual machine image from Docker images*
The project is heavily inspired by the [article](https://iximiuz.com/en/posts/from-docker-container-to-bootable-linux-disk-image/) and the work done by [iximiuz](https://github.com/iximiuz) on [docker-to-linux](https://github.com/iximiuz/docker-to-linux).
Many thanks to him.
**Status**: *alpha*
[![asciicast](https://asciinema.org/a/520132.svg)](https://asciinema.org/a/520132)
## Supported Environments:
**Only building Linux Virtual Machine images is supported.**
Starting from v0.1.0, **d2vm** automatically run build and convert commands inside Docker when not running on linux
or when running without *root* privileges.
*Note: windows should be working, but is totally untested.*
## Supported VM Linux distributions:
Working and tested:
- [x] Ubuntu (18.04+)
- [x] Debian (stretch+)
- [x] Alpine
- [x] 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.
## Prerequisites
### osx
- [Docker](https://docs.docker.com/get-docker/)
- [QEMU](https://www.qemu.org/download/#macos) (optional)
- [VirtualBox](https://www.virtualbox.org/wiki/Downloads) (optional)
### Linux
- [Docker](https://docs.docker.com/get-docker/)
- util-linux
- udev
- parted
- e2fsprogs
- mount
- tar
- extlinux
- qemu-utils
- cryptsetup (when using LUKS)
- [QEMU](https://www.qemu.org/download/#linux) (optional)
- [VirtualBox](https://www.virtualbox.org/wiki/Linux_Downloads) (optional)
## Getting started
### Install
#### With Docker
*Note: this will only work if both the source context (and Dockerfile) and the output directory are somewhere inside
the directory where you run the command.*
```bash
docker pull linkacloud/d2vm:latest
alias d2vm="docker run --rm -it -v /var/run/docker.sock:/var/run/docker.sock --privileged -v \$PWD:/d2vm -w /d2vm linkacloud/d2vm:latest"
```
```bash
wich d2vm
d2vm: aliased to docker run --rm -it -v /var/run/docker.sock:/var/run/docker.sock --privileged -v $PWD:/d2vm -w /d2vm linkacloud/d2vm:latest
```
#### With Homebrew
```bash
brew install linka-cloud/tap/d2vm
```
#### From release
Download the latest release for your platform from the [release page](https://github.com/linka-cloud/d2vm/releases/latest).
Extract the tarball, then move the extracted *d2vm* binary to somewhere in your `$PATH` (`/usr/local/bin` for most users).
```bash
VERSION=$(git ls-remote --tags https://github.com/linka-cloud/d2vm |cut -d'/' -f 3|tail -n 1)
OS=$(uname -s | tr '[:upper:]' '[:lower:]')
ARCH=$([ "$(uname -m)" = "x86_64" ] && echo "amd64" || echo "arm64")
curl -sL "https://github.com/linka-cloud/d2vm/releases/download/${VERSION}/d2vm_${VERSION}_${OS}_${ARCH}.tar.gz" | tar -xvz d2vm
sudo mv d2vm /usr/local/bin/
```
#### From source
Clone the git repository:
```bash
git clone https://github.com/linka-cloud/d2vm && cd d2vm
```
Install using the *make*, *docker* and the Go tool chain:
```bash
make install
```
The *d2vm* binary is installed in the `$GOBIN` directory.
```bash
which d2vm
/go/bin/d2vm
```
### Generate shell completion
The *d2vm* program supports shell completion for *bash*, *zsh* and *fish*.
It can be enabled by running the following command:
```bash
source <(d2vm completion $(basename $SHELL))
```
Or you can install the completion file in the shell completion directory by following the instructions:
```bash
d2vm completion $(basename $SHELL) --help
```
### Converting an existing Docker Image to VM image:
```bash
d2vm convert --help
```
```
Convert Docker image to vm image
Usage:
d2vm convert [docker image] [flags]
Flags:
--append-to-cmdline string Extra kernel cmdline arguments to append to the generated one
--boot-size uint Size of the boot partition in MB (default 100)
--force Override output qcow2 image
-h, --help help for convert
--keep-cache Keep the images after the build
--luks-password string Password to use for the LUKS encrypted root partition. If not set, the root partition will not be encrypted
--network-manager string Network manager to use for the image: none, netplan, ifupdown
-o, --output string The output image, the extension determine the image format, raw will be used if none. Supported formats: qcow2 qed raw vdi vhd vmdk (default "disk0.qcow2")
-p, --password string Optional root user password
--pull Always pull docker image
--push Push the container disk image to the registry
--raw Just convert the container to virtual machine image without installing anything more
-s, --size string The output image size (default "10G")
--split-boot Split the boot partition from the root partition
-t, --tag string Container disk Docker image tag
Global Flags:
--time string Enable formated timed output, valide formats: 'relative (rel | r)', 'full (f)' (default "none")
-v, --verbose Enable Verbose output
```
Create an image based on the **ubuntu** official image:
```bash
sudo d2vm convert ubuntu -o ubuntu.qcow2 -p MyP4Ssw0rd
```
```
Pulling image ubuntu
Inspecting image ubuntu
No network manager specified, using distribution defaults: netplan
Docker image based on Ubuntu 22.04.1 LTS (Jammy Jellyfish)
Building kernel enabled image
Creating vm image
Creating raw image
Mounting raw image
Creating raw image file system
Copying rootfs to raw image
Setting up rootfs
Installing linux kernel
Unmounting raw image
Writing MBR
Converting to qcow2
```
You can now run your ubuntu image using the created `ubuntu.qcow2` image with **qemu**:
```bash
d2vm run qemu ubuntu.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:
```bash
cd examples
```
*ubuntu.Dockerfile* :
```dockerfile
FROM ubuntu
RUN apt update && apt install -y openssh-server && \
echo "PermitRootLogin yes" >> /etc/ssh/sshd_config
```
Build the vm image:
The *build* command take most of its flags and arguments from the *docker build* command.
```bash
d2vm build --help
```
```
Build a vm image from Dockerfile
Usage:
d2vm build [context directory] [flags]
Flags:
--append-to-cmdline string Extra kernel cmdline arguments to append to the generated one
--boot-size uint Size of the boot partition in MB (default 100)
--build-arg stringArray Set build-time variables
-f, --file string Name of the Dockerfile
--force Override output qcow2 image
-h, --help help for build
--keep-cache Keep the images after the build
--luks-password string Password to use for the LUKS encrypted root partition. If not set, the root partition will not be encrypted
--network-manager string Network manager to use for the image: none, netplan, ifupdown
-o, --output string The output image, the extension determine the image format, raw will be used if none. Supported formats: qcow2 qed raw vdi vhd vmdk (default "disk0.qcow2")
-p, --password string Optional root user password
--push Push the container disk image to the registry
--raw Just convert the container to virtual machine image without installing anything more
-s, --size string The output image size (default "10G")
--split-boot Split the boot partition from the root partition
-t, --tag string Container disk Docker image tag
Global Flags:
--time string Enable formated timed output, valide formats: 'relative (rel | r)', 'full (f)' (default "none")
-v, --verbose Enable Verbose output
```
```bash
sudo d2vm build -p MyP4Ssw0rd -f ubuntu.Dockerfile -o ubuntu.qcow2 .
```
Or if you want to create a VirtualBox image:
```bash
sudo d2vm build -p MyP4Ssw0rd -f ubuntu.Dockerfile -o ubuntu.vdi .
```
### KubeVirt Container Disk Images
Using the `--tag` flag with the `build` and `convert` commands, you can create a
[Container Disk Image](https://kubevirt.io/user-guide/virtual_machines/disks_and_volumes/#containerdisk) for [KubeVirt](https://kubevirt.io/).
The `--push` flag will push the image to the registry.
### Complete example
A complete example setting up a ZSH workstation is available in the [examples/full](examples/full/README.md) directory.
### Internal Dockerfile templates
You can find the Dockerfiles used to install the Kernel in the [templates](templates) directory.
### TODO / Questions:
- [ ] Create service from `ENTRYPOINT` `CMD` `WORKDIR` and `ENV` instructions ?
- [ ] Inject Image `ENV` variables into `.bashrc` or other service environment file ?
- [x] Use image layers to create *rootfs* instead of container ?
### Acknowledgments
The *run* commands are adapted from [linuxkit](https://github.com/docker/linuxkit).