Fast local VMs for Linux with KVM, QEMU, and cloud-init.

Yeast is a project-based VM tool for Linux. You describe one or more machines in yeast.yaml, pull a trusted base image, run yeast up, and Yeast handles the local QEMU/KVM lifecycle for you.

It is built for people who want:

• real VMs, not containers
• a simpler local workflow than older VM tooling
• cloud-init based guest setup
• repeatable terminal-friendly automation

If the repository is reachable over HTTPS:

curl -fsSL https://raw.githubusercontent.com/Twarga/yeast/main/install.sh | bash

If you already cloned the repo:

bash install.sh

What the installer does:

• detects the Linux package manager
• installs Yeast dependencies
• installs Go for the source-build path
• clones and builds Yeast
• installs yeast into /usr/local/bin
• creates ~/.yeast/cache/
• generates an SSH key if needed
• adds the user to the kvm group when possible

Optional overrides:

YEAST_REPO_URL=https://github.com/Twarga/yeast.git YEAST_REF=main bash install.sh

Important:

• if the repo is private, direct install only works for users who already have access
• if the installer adds you to the kvm group, log out and back in before your first yeast up

git clone https://github.com/Twarga/yeast.git
cd yeast
go build -o yeast ./cmd/yeast
sudo mv yeast /usr/local/bin/

Yeast currently supports:

• Linux only

Yeast needs:

• KVM support on the host
• qemu-system-x86_64
• qemu-img
• genisoimage
• ssh
• an SSH public key in ~/.ssh/id_ed25519.pub or ~/.ssh/id_rsa.pub

Typical package installs:

# Ubuntu / Debian
sudo apt install qemu-system-x86 qemu-utils genisoimage

# Fedora / RHEL
sudo dnf install qemu-system-x86 qemu-img genisoimage

# Arch Linux
sudo pacman -S qemu-base cdrtools

If needed, add your user to the kvm group:

sudo usermod -aG kvm $USER

yeast doctor

mkdir my-project
cd my-project
yeast init

Default starter config:

version: 1
instances:
  - name: web
    image: ubuntu-22.04
    memory: 1024
    cpus: 1
    disk_size: 20G
    user: yeast
    sudo: none

You can also generate the starter config with your own values:

yeast init \
  --name api \
  --image ubuntu-24.04 \
  --memory 2048 \
  --cpus 2 \
  --disk-size 25G \
  --user operator \
  --sudo password

List supported images:

yeast pull --list

Pull one:

yeast pull ubuntu-22.04

Current built-in trusted images:

• ubuntu-22.04
• ubuntu-24.04

yeast up

yeast status

Example output:

NAME    STATUS    PID     IP           SSH PORT
web     running   12345   127.0.0.1    45678

For scripts:

yeast status --json

yeast ssh web

If your bootstrap user is different:

yeast ssh web --user operator

yeast down

version: 1
instances:
  - name: web
    image: ubuntu-22.04
    memory: 2048
    cpus: 2
    disk_size: 25G
    user: yeast
    sudo: password
    env:
      APP_ENV: development
      LOG_LEVEL: debug

Supported fields today:

• name
• image
• memory
• cpus
• disk_size
• user
• sudo
• env
• user_data

Important behavior:

• user_data, if provided, replaces Yeast's generated cloud-init
• custom user_data does not automatically merge your SSH key, user, sudo policy, or env values
• disk_size creates a larger overlay disk on first boot and grows an existing disk when the configured size increases
• Yeast does not provide reusable cloud-init templates or presets yet; custom provisioning is raw user_data

Yeast supports 3 network modes on up and restart:

Examples:

yeast up --network-mode user
yeast up --network-mode private
yeast up --network-mode bridge --bridge br0
yeast restart web --network-mode bridge --bridge br0

Current networking limits:

• only SSH port forwarding is built in
• no custom 8080:80 style forwards yet
• network mode is selected at command time
• network mode is not stored in yeast.yaml

Most major commands support:

yeast <command> --json

yeast ssh is interactive and does not support JSON output.

Project directory:

• yeast.yaml: desired VM definitions
• yeast.state: runtime state for the current project

Home directory:

• ~/.yeast/cache/: shared base images
• ~/.yeast/instances/<name>/: per-instance runtime files

Each instance directory typically contains:

• disk.qcow2
• seed.iso
• user-data
• meta-data
• vm.log

Yeast is intentionally small right now.

Current non-goals or missing features:

• Linux only
• no GUI
• no global VM inventory command
• no arbitrary port-forward configuration
• no snapshots or suspend/resume
• no per-instance yeast up <name>
• no guest IP discovery in bridge mode

For the full user guide, see docs.md.

Also useful:

• CONTRIBUTING.md
• CHANGELOG.md
• LICENSE