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threefoldtech / vbuilders

builders based on docker
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end2end example for os -> vbuilder -> flist tfhub -> ... #66

Open despiegk opened 8 months ago

despiegk commented 8 months ago

requirements

despiegk commented 8 months ago

I have a very fast machine at 65.21.132.119, give me your ssh key will add it please use btrfs and subvolumes starting from snapshots to speed up and keep diskspace under control

despiegk commented 8 months ago

over weekend Kristof will check the vbuilders again, to make sure they work properly, will also revive the 3script way, which might be even easier how to build them

despiegk commented 8 months ago

I just asked chatgpt

Creating a Dockerfile and a bash script to build an Alpine Linux OS image and export it to a QCOW2 format for use with Cloud Hypervisor involves several steps. I'll outline the process and provide you with the necessary scripts.

Dockerfile

First, let's create a Dockerfile to build an Alpine Linux environment. Dockerfiles typically don't export to QCOW2 directly, but we can set up the environment:

# Use Alpine Linux as the base image
FROM alpine:latest

# Install necessary packages
RUN apk add --no-cache \
    qemu-img \
    qemu-system-x86_64

# Set the work directory
WORKDIR /alpine

# Copy the script to build and export the QCOW2 image
COPY export-qcow2.sh /alpine

# Set the script as executable
RUN chmod +x /alpine/export-qcow2.sh

Bash Script (export-qcow2.sh)

This script will be responsible for creating a raw Alpine Linux disk image and converting it to QCOW2 format. Place this script in the same directory as your Dockerfile.

#!/bin/bash

# Set the image size
IMAGE_SIZE=1G

# Create a raw disk image
dd if=/dev/zero of=alpine.raw bs=1M count=$((IMAGE_SIZE))

# Format the disk image
mkfs.ext4 alpine.raw

# Mount the image
mkdir /mnt/alpine
mount -o loop alpine.raw /mnt/alpine

# Install Alpine Linux to the raw image
apk add alpine-base --root /mnt/alpine

# Unmount the image
umount /mnt/alpine
rmdir /mnt/alpine

# Convert the raw image to QCOW2 format
qemu-img convert -f raw -O qcow2 alpine.raw alpine.qcow2

# Move the QCOW2 image to a shared volume
mv alpine.qcow2 /shared/

Building and Running the Docker Container

You need to build the Docker container and then run it, mounting a shared volume to retrieve the QCOW2 file. Here's a bash script to do that:

#!/bin/bash

# Build the Docker image
docker build -t alpine-qcow2-builder .

# Create a directory to hold the exported QCOW2 image
mkdir -p /path/to/shared/volume

# Run the container, mounting the shared volume
docker run --rm -v /path/to/shared/volume:/shared alpine-qcow2-builder ./export-qcow2.sh

Replace /path/to/shared/volume with the path where you want to store the exported QCOW2 file.

Notes

After running these scripts, you should find the alpine.qcow2 file in the specified shared volume directory, ready for use with Cloud Hypervisor.

despiegk commented 8 months ago

Running a virtual machine using the Cloud Hypervisor with a QCOW2 image requires a different approach compared to QEMU. Cloud Hypervisor is a Virtual Machine Monitor (VMM) that leverages cloud-native technologies and is specifically designed for modern cloud workloads. Below is a bash script that demonstrates how to start a VM using Cloud Hypervisor with your Alpine Linux QCOW2 image.

Script: run-vm-cloudhypervisor.sh

This script assumes that you have Cloud Hypervisor installed on your system and the alpine.qcow2 image ready.

#!/bin/bash

# Path to the Cloud Hypervisor executable
CLOUD_HYPERVISOR_PATH="cloud-hypervisor"  # Update this if your cloud-hypervisor binary is in a different location

# Path to the QCOW2 image
QCOW2_IMAGE_PATH="/path/to/alpine.qcow2"

# Check if the Cloud Hypervisor binary exists
if [ ! -x "$(command -v $CLOUD_HYPERVISOR_PATH)" ]; then
    echo "Cloud Hypervisor binary not found"
    exit 1
fi

# Check if the QCOW2 image exists
if [ ! -f "$QCOW2_IMAGE_PATH" ]; then
    echo "QCOW2 image not found at $QCOW2_IMAGE_PATH"
    exit 1
fi

# Define VM specifications
MEMORY_SIZE="512M"       # RAM size
CPU_COUNT=2              # Number of CPU cores
DISK_PATH=$QCOW2_IMAGE_PATH
KERNEL_PATH="/path/to/vmlinuz"  # Path to the Linux kernel image
CMDLINE="root=/dev/vda1 console=ttyS0" # Kernel command line parameters

# Start the virtual machine
$CLOUD_HYPERVISOR_PATH \
    --cpus boot=$CPU_COUNT \
    --memory size=$MEMORY_SIZE \
    --kernel $KERNEL_PATH \
    --cmdline "$CMDLINE" \
    --disk path=$DISK_PATH \
    --net "tap=,mac=,ip=,mask=" \
    --console off \
    --serial tty

echo "VM started with Alpine Linux."

Usage Instructions

  1. Replace /path/to/alpine.qcow2 with the actual path to your QCOW2 image.
  2. The script assumes the cloud-hypervisor binary is in your PATH. If it's in a different location, update the CLOUD_HYPERVISOR_PATH variable accordingly.
  3. You need a Linux kernel image (vmlinuz). Update the KERNEL_PATH variable with the path to this kernel image.
  4. Adjust the MEMORY_SIZE, CPU_COUNT, and other parameters as per your requirement.
  5. Make sure the script has execute permissions: 
    chmod +x run-vm-cloudhypervisor.sh
  6. Run the script: 
    ./run-vm-cloudhypervisor.sh

Important Notes

This script should help you start a VM with Alpine Linux using Cloud Hypervisor and your QCOW2 image. Adjustments may be necessary based on your specific environment and requirements.