These constants still referenced the long removed (separate vhost-user structs.) Signed-off-by: Rob Bradford <robert.bradford@intel.com> |
||
---|---|---|
.github | ||
acpi_tables | ||
api_client | ||
arch | ||
block_util | ||
devices | ||
docs | ||
event_monitor | ||
fuzz | ||
hypervisor | ||
net_gen | ||
net_util | ||
option_parser | ||
pci | ||
performance-metrics | ||
qcow | ||
rate_limiter | ||
resources | ||
scripts | ||
serial_buffer | ||
src | ||
test_data/cloud-init/ubuntu | ||
test_infra | ||
tests | ||
tracer | ||
vfio_user | ||
vhdx | ||
vhost_user_block | ||
vhost_user_net | ||
virtio-devices | ||
vm-allocator | ||
vm-device | ||
vm-migration | ||
vm-virtio | ||
vmm | ||
.gitignore | ||
.rustfmt.toml | ||
build.rs | ||
Cargo.lock | ||
Cargo.toml | ||
CODE_OF_CONDUCT.md | ||
CODEOWNERS | ||
CONTRIBUTING.md | ||
CREDITS.md | ||
Jenkinsfile | ||
LICENSE-APACHE | ||
LICENSE-BSD-3-Clause | ||
MAINTAINERS.md | ||
README.md | ||
release-notes.md |
- 1. What is Cloud Hypervisor?
- 2. Getting Started
- 3. Status
- 4.
rust-vmm
project dependency - 5. Community
1. What is Cloud Hypervisor?
Cloud Hypervisor is an open source Virtual Machine Monitor (VMM) that runs on top of KVM hypervisor and Microsoft Hypervisor (MSHV).
The project focuses on exclusively running modern, cloud workloads, on top of a limited set of hardware architectures and platforms. Cloud workloads refers to those that are usually run by customers inside a cloud provider. For our purposes this means modern operating systems with most I/O handled by paravirtualised devices (i.e. virtio), no requirement for legacy devices, and 64-bit CPUs.
Cloud Hypervisor is implemented in Rust and is based on the rust-vmm crates.
Objectives
High Level
- Runs on KVM or MSHV
- Minimal emulation
- Low latency
- Low memory footprint
- Low complexity
- High performance
- Small attack surface
- 64-bit support only
- CPU, memory, PCI hotplug
- Machine to machine migration
Architectures
Cloud Hypervisor supports the x86-64
and AArch64
architectures. There are
some small differences in functionality between the two architectures
(see #1125).
Guest OS
Cloud Hypervisor supports 64-bit Linux
and Windows 10/Windows Server 2019.
2. Getting Started
Below sections describe how to build and run Cloud Hypervisor on the x86_64
platform. For getting started on the AArch64
platform, please refer to the
Arm64 documentation.
Host OS
Based on required KVM functionality the minimum host kernel version is 4.11. For adequate peformance the minimum recommended host kernel vesion is 5.6. The majority of the CI currently tests with kernel version 5.15.
Preparation
We create a folder to build and run cloud-hypervisor
at $HOME/cloud-hypervisor
$ export CLOUDH=$HOME/cloud-hypervisor
$ mkdir $CLOUDH
Install prerequisites
You need to install some prerequisite packages in order to build and test Cloud Hypervisor. Here, all the steps are based on Ubuntu, for other Linux distributions please replace the package manager and package name.
# Install build-essential, git, and qemu-utils
$ sudo apt install git build-essential qemu-utils
# Install rust tool chain
$ curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
# If you want to build statically linked binary please add musl target
$ rustup target add x86_64-unknown-linux-musl
Clone and build
First you need to clone and build the cloud-hypervisor repo:
$ pushd $CLOUDH
$ git clone https://github.com/cloud-hypervisor/cloud-hypervisor.git
$ cd cloud-hypervisor
$ cargo build --release
# We need to give the cloud-hypervisor binary the NET_ADMIN capabilities for it to set TAP interfaces up on the host.
$ sudo setcap cap_net_admin+ep ./target/release/cloud-hypervisor
# If you want to build statically linked binary
$ cargo build --release --target=x86_64-unknown-linux-musl --all
$ popd
This will build a cloud-hypervisor
binary under
$CLOUDH/cloud-hypervisor/target/release/cloud-hypervisor
.
Containerized builds and tests
If you want to build and test Cloud Hypervisor without having to install all the
required dependencies (The rust toolchain, cargo tools, etc), you can also use
Cloud Hypervisor's development script: dev_cli.sh
. Please note that upon its
first invocation, this script will pull a fairly large container image.
For example, to build the Cloud Hypervisor release binary:
$ pushd $CLOUDH
$ cd cloud-hypervisor
$ ./scripts/dev_cli.sh build --release
With dev_cli.sh
, one can also run the Cloud Hypervisor CI locally. This can be
very convenient for debugging CI errors without having to fully rely on the
Cloud Hypervisor CI infrastructure.
For example, to run the Cloud Hypervisor unit tests:
$ ./scripts/dev_cli.sh tests --unit
Run the ./scripts/dev_cli.sh --help
command to view all the supported
development script commands and their related options.
Use Prebuilt Binaries
Cloud Hypervisor packages targeting some popular Linux distributions are available thanks to the Open Build Service. The OBS README explains how to enable the repository in a supported Linux distribution and install Cloud Hypervisor and accompanying packages. Please report any packaging issues in the obs-packaging repository.
Run
You can run a guest VM by either using an existing cloud image or booting into your own kernel and disk image.
Cloud image
Cloud Hypervisor supports booting disk images containing all needed
components to run cloud workloads, a.k.a. cloud images. To do that we rely on
the Rust Hypervisor
Firmware project
to provide an ELF formatted KVM firmware for cloud-hypervisor
to directly
boot into.
We need to get the latest rust-hypervisor-firmware
release and also a working
cloud image. Here we will use a Ubuntu image:
$ pushd $CLOUDH
$ wget https://cloud-images.ubuntu.com/focal/current/focal-server-cloudimg-amd64.img
$ qemu-img convert -p -f qcow2 -O raw focal-server-cloudimg-amd64.img focal-server-cloudimg-amd64.raw
$ wget https://github.com/cloud-hypervisor/rust-hypervisor-firmware/releases/download/0.4.1/hypervisor-fw
$ popd
$ pushd $CLOUDH
$ sudo setcap cap_net_admin+ep ./cloud-hypervisor/target/release/cloud-hypervisor
$ ./cloud-hypervisor/target/release/cloud-hypervisor \
--kernel ./hypervisor-fw \
--disk path=focal-server-cloudimg-amd64.raw \
--cpus boot=4 \
--memory size=1024M \
--net "tap=,mac=,ip=,mask="
$ popd
Multiple arguments can be given to the --disk
parameter.
Custom kernel and disk image
Building your kernel
Cloud Hypervisor also supports direct kernel boot into a vmlinux
ELF kernel.
In order to support virtio-watchdog we have our own development branch. You are
of course able to use your own kernel but these instructions will continue with
the version that we develop and test against.
To build the kernel:
# Clone the Cloud Hypervisor Linux branch
$ pushd $CLOUDH
$ git clone --depth 1 https://github.com/cloud-hypervisor/linux.git -b ch-5.15.12 linux-cloud-hypervisor
$ pushd linux-cloud-hypervisor
# Use the cloud-hypervisor kernel config to build your kernel
$ cp $CLOUDH/cloud-hypervisor/resources/linux-config-x86_64 .config
$ KCFLAGS="-Wa,-mx86-used-note=no" make bzImage -j `nproc`
$ popd
The vmlinux
kernel image will then be located at
linux-cloud-hypervisor/arch/x86/boot/compressed/vmlinux.bin
.
Disk image
For the disk image, we will use a Ubuntu cloud image that contains a root partition:
$ pushd $CLOUDH
$ wget https://cloud-images.ubuntu.com/focal/current/focal-server-cloudimg-amd64.img
$ qemu-img convert -p -f qcow2 -O raw focal-server-cloudimg-amd64.img focal-server-cloudimg-amd64.raw
$ popd
Booting the guest VM
Now we can directly boot into our custom kernel and make it use the Ubuntu root partition. If we want to have 4 vCPUs and 1024 MBytes of memory:
$ pushd $CLOUDH
$ sudo setcap cap_net_admin+ep ./cloud-hypervisor/target/release/cloud-hypervisor
$ ./cloud-hypervisor/target/release/cloud-hypervisor \
--kernel ./linux-cloud-hypervisor/arch/x86/boot/compressed/vmlinux.bin \
--disk path=focal-server-cloudimg-amd64.raw \
--cmdline "console=hvc0 root=/dev/vda1 rw" \
--cpus boot=4 \
--memory size=1024M \
--net "tap=,mac=,ip=,mask="
The above example use the virtio-console
device as the guest console, and this
device may not be enabled soon enough by the guest kernel to get early kernel
debug messages.
When in need for earlier debug messages, using the legacy serial device based console is preferred:
$ ./cloud-hypervisor/target/release/cloud-hypervisor \
--kernel ./linux-cloud-hypervisor/arch/x86/boot/compressed/vmlinux.bin \
--console off \
--serial tty \
--disk path=focal-server-cloudimg-amd64.raw \
--cmdline "console=ttyS0 root=/dev/vda1 rw" \
--cpus boot=4 \
--memory size=1024M \
--net "tap=,mac=,ip=,mask="
3. Status
Cloud Hypervisor is under active development. The following stability guarantees are currently made:
-
The API (including command line options) will not be removed or changed in a breaking way without a minimum of 2 major releases notice. Where possible warnings will be given about the use of deprecated functionality and the deprecations will be documented in the release notes.
-
Point releases will be made between individual releases where there are substantial bug fixes or security issues that need to be fixed. These point releases will only include bug fixes.
Currently the following items are not guaranteed across updates:
- Snapshot/restore is not supported across different versions
- Live migration is not supported across different versions
- The following features are considered experimental and may change substantially between releases: TDX, vfio-user, vDPA.
As of 2022-04-05, the following cloud images are supported:
- Ubuntu Bionic (cloudimg)
- Ubuntu Focal (cloudimg)
- Ubuntu Jammy (cloudimg)
Direct kernel boot to userspace should work with a rootfs from most distributions.
Further details can be found in the release documentation.
Hot Plug
Cloud Hypervisor supports hotplug of CPUs, passthrough devices (VFIO),
virtio-{net,block,pmem,fs,vsock}
and memory resizing. This
document details how to add devices to a running VM.
Device Model
Details of the device model can be found in this documentation.
TODO
We are not tracking the Cloud Hypervisor TODO list from a specific git tracked file but through github issues instead.
Roadmap
The project roadmap is tracked through a GitHub project.
4. rust-vmm
project dependency
In order to satisfy the design goal of having a high-performance, security-focused hypervisor the decision was made to use the Rust programming language. The language's strong focus on memory and thread safety makes it an ideal candidate for implementing VMMs.
Instead of implementing the VMM components from scratch, Cloud Hypervisor is importing the rust-vmm crates, and sharing code and architecture together with other VMMs like e.g. Amazon's Firecracker and Google's crosvm.
Cloud Hypervisor embraces the rust-vmm project goals, which is to be able to share and re-use as many virtualization crates as possible. As such, the Cloud Hypervisor relationship with the rust-vmm project is twofold:
- It will use as much of the rust-vmm code as possible. Any new rust-vmm crate that's relevant to the project goals will be integrated as soon as possible.
- As it is likely that the rust-vmm project will lack some of the features that Cloud Hypervisor needs (e.g. ACPI, VFIO, vhost-user, etc), we will be using the Cloud Hypervisor VMM to implement and test them, and contribute them back to the rust-vmm project.
Firecracker and crosvm
A large part of the Cloud Hypervisor code is based on either the Firecracker or the crosvm projects implementations. Both of these are VMMs written in Rust with a focus on safety and security, like Cloud Hypervisor.
However we want to emphasize that the Cloud Hypervisor project is neither a fork nor a reimplementation of any of those projects. The goals and use cases we're trying to meet are different. We're aiming at supporting cloud workloads, i.e. those modern, full Linux distribution images currently being run by Cloud Service Provider (CSP) tenants.
Our primary target is not to support client or serverless use cases, and as such our code base already diverges from the crosvm and Firecracker ones. As we add more features to support our use cases, we believe that the divergence will increase while at the same time sharing as much of the fundamental virtualization code through the rust-vmm project crates as possible.
5. Community
The Cloud Hypervisor project follows the governance, and community guidelines described in the Community repository.
Contribute
We are working on building a global, diverse and collaborative community around the Cloud Hypervisor project. Anyone who is interested in contributing to the project is welcome to participate.
We believe that contributing to a open source project like Cloud Hypervisor covers a lot more than just sending code. Testing, documentation, pull request reviews, bug reports, feature requests, project improvement suggestions, etc, are all equal and welcome means of contribution. See the CONTRIBUTING document for more details.
Slack
Get an invite to our Slack channel and join us on Slack.
Mailing list
Please report bugs using the GitHub issue tracker but for broader community discussions you may use our mailing list.
Security issues
Please contact the maintainers listed in the MAINTAINERS.md file with security issues.