Lucky Abolorunke
bce9366b3d
### Why
The README Quickstart covers getting a local Substrate cluster running
with
the default gVisor runtime, but there's no documentation for the
micro-VM
runtime, where the friction can't be scripted away: it requires
`/dev/kvm`
(bare metal, nested virtualization, or Lima on macOS), and on Apple
Silicon
the Lima configuration and asset assembly are non-obvious. New
contributors
have to reverse-engineer the `hack/` scripts.
### What
Adds `docs/dev/microvm-local.md` — "Running the microVM runtime locally"
— a
focused guide covering only the microVM delta, based on notes from real
onboarding runs. General setup is deferred to the README Quickstart
(listed
as the guide's prerequisite) rather than duplicated:
- **Option A: Linux host with KVM** — verifying `/dev/kvm` and CPU virt
support, the rootless-Docker caveat for the KVM probe, cluster creation,
and the one-shot `run-microvm-demo-kind.sh` bring-up.
- **Option B: Apple Silicon macOS via Lima** — nested virtualization
with the
guest image pinned to Ubuntu 25.10 (until the kernel issue in the
default
image is fixed), `vzNAT` networking, and assembling the arm64 assets
inside
the Lima guest (`assemble.sh` requires a Linux host of the target arch).
- **Trying it out** — defers to the next steps the demo script prints
and
links the counter demo's micro-VM variant, instead of duplicating those
commands.
- **Troubleshooting** — symptom → root cause → fix entries actually hit
during onboarding (rootless-Docker KVM probe failures, the `aws` CLI
staging requirement until #804 lands, arm64 `virtiofsd` build deps, M1
lacking FEAT_NV2).
4.4 KiB
How to Contribute
We would love to accept your patches and contributions to this project. Before you spend a lot of time on a contribution, please review the following guidelines.
Before you begin
Sign our Contributor License Agreement
Contributions to this project must be accompanied by a Contributor License Agreement (CLA). You (or your employer) retain the copyright to your contribution; this simply gives us permission to use and redistribute your contributions as part of the project.
If you or your current employer have already signed the Google CLA (even if it was for a different project), you probably don't need to do it again.
Visit https://cla.developers.google.com/ to see your current agreements or to sign a new one.
Review our Community Guidelines
This project follows Google's Open Source Community Guidelines.
Set up a local development environment
The Quickstart (Development) in the README
covers bringing up a local cluster with the default (gVisor) runtime. To run
the microVM runtime locally — which needs /dev/kvm, or Lima nested
virtualization on Apple Silicon — see
docs/dev/microvm-local.md.
Contribution process
This is a very new project, so we are still working out exactly how it is going to be developed. For now, we are focused on iterating quickly to find the right design and architecture. This has implications for contributors:
-
Things are moving quickly, so PRs may need to be rebased or updated frequently. Small PRs that are focused on a single issue or feature are easier to review and update than large PRs that touch many different parts of the codebase.
-
While we welcome new contributors, we are really focused on the minimal capabilities needed to make this project useful. Before you start a new contribution, please discuss it with us first (if there is an issue open, comment there and if not, open one). We want to make sure that your work is aligned with our near-term goals for the project and that we are not duplicating work that is already in flight.
-
PRs which are not aligned with our near-term goals may be closed without extensive review. We are not trying to be discouraging, but we need to make sure that we are focused on the most important work.
Sizing PRs for review
We optimize PRs for easy review — large PRs get broken down, small PRs get merged.
- Large PRs: split huge changes into a series of smaller PRs, each a logically distinct feature. When the intermediate steps are not useful on their own, keep the change as one PR split into commits at logical break points, and preserve those commits on merge.
- Small and bulk PRs: if you find a typo, review the whole file and fix everything in one pass rather than sending the single edit. Group related typo, doc, and single-line cleanup fixes into one PR rather than opening several small ones for the same area. Maintainers may ask you to consolidate fragmented PRs into one, or close them in favor of a combined submission.
As a rough scale: S is under 30 changed lines, M under 100, L under 500, XL under 1000. Most PRs should be L or smaller; XL and above are candidates for breaking down.
Code Reviews
All submissions, including submissions by project members, require review. We use GitHub pull requests for this purpose.
All code changes should be accompanied by tests. We will not merge code that does not have tests, and we will not merge code that causes tests to fail.
Root-gated tests
Tests that need root (overlay mounts, mknod, trusted.* xattrs, ...) call
roottest.Require(t, ...) from internal/roottest as
their first statement. They skip in a plain go test ./...; CI reruns every
package whose tests import that package under sudo. To run them locally:
hack/run-root-tests.sh
New privileged tests only need the roottest.Require call — no CI changes.
Copyright Headers
Every file containing source code must include copyright and license information. This includes any JS/CSS files that you might be serving out to browsers. (This is to help well-intentioned people avoid accidental copying that doesn't comply with the license.)
Our standard headers for various filetypes can be found in ./hack/boilerplate.