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Show HN: Kedge – Full-stack cloud with forkable VM snapshots and global SQLite (kedge.dev)

141 points by wgjordan ↗ HN
I'm building Kedge, a globally distributed platform for stateful serverless apps. Here's how you make a simple static site: `echo '# Hello world!' | ssh kedge.dev`

I helped build Fly.io for 4 years and shared enthusiasm for the founders' vision of a 'global Heroku'. While there, I wrote "The Serverless Server" (https://fly.io/blog/the-serverless-server/) as a study of Lambda and a sketch of a modern serverless product built around lightweight VMs. That essay was the initial inspiration for Kedge.

Kedge has a fast VM orchestrator that can create code sandboxes or scale service instances in 3ms, using a combination of forkable VM snapshots and a tree of warm pools (Linux kernel -> base runtime -> app). VMs are memory-dense thanks to shared copy-on-write memory pages. You can run lightweight CGI-style functions, public OCI images, or source code for BuildKit to compile and deploy.

Kedge's global control plane sits on an eventually-consistent SQLite database. Taking inspiration from Corrosion and Litestream, I built a local-first, multi-writer CRDT-based replication system backed by object storage, and just recently made it open source (https://github.com/wjordan/syzy).

You can also use a SQLite client to query `/shared.db` from any instance for a build-in replicated database in your app. This lets Kedge autoscale services close to your users while each instance queries its local replica for eventually-consistent data, with no need to micro-manage instance or volume placement. (There's also a /shared/ filesystem adapter for convenience.)

Kedge can even use this same database for stateful, server-rendered HTML apps. Data attributes bind forms, buttons, and values to records in the app database, Kedge compiles the schema and operations at deploy-time, and then queries the local data to serve requests. As a demo, I made a Hacker News clone with story submission, votes, comments and auth in about 60 lines of Markdown, plus CSS (https://kedge.dev/docs/html-apps#kedger-news).

I've just started collecting public feedback, so please let me know what you think! I'm particularly interested in feedback on the stateful HTML app model, which is the newest (and most ambitious) piece. The preview is currently running in 11 regions for you to kick the tires. There's no billing yet, so the pricing page is an estimate. Thanks for taking a look!

14 comments

[ 2.6 ms ] story [ 122 ms ] thread
vyedin
this is super cool, bookmarking to give it a whirl

> As a demo, I made a Hacker News clone with story submission, votes, comments and auth in about 60 lines of Markdown, plus CSS

although why would you use it for evil

tekacs
This is phenomenal, great work!

On the HN frontpage is Superlogical (I have no affiliation) right now, and I used the shell provided by the Kedge News demo to `ssh superlogical.jobs` from my browser on a phone on an instance started seconds earlier. :)

I didn't immediately spot the durability contract for volumes -- local NVMe like Fly, or sitting on some underlying system like EBS?

PersonalJarvis
Two questions about the fork boundary. The snapshot is taken once when the process calls listen, so every later instance is a clone of the same frozen memory image, and anything seeded during init is identical across every clone in every region. That is exactly what the Linux vmgenid driver exists for, and it is why Lambda SnapStart had to ship explicit reseeding guidance. I could not find entropy, RNG or reseed anywhere in the runtime, performance or security docs, so is there a post-restore reseed hook, and does it fire before the first accept?

The other one is syzy. CRDT.md says eviction is operator-driven, that PRUNING.md is a design-stage contract and not yet code, and that a replica lagging beyond the hold window may transiently observe the departing duplicate, while the product headline offers scale to zero when idle, which mints offline replicas continuously. Who calls syzy_evict in the managed product?

ianberdin
Fun fact: we also built our cloud platform based on Fly.io’s ideas, but we supercharged it with a custom Rust filesystem.

This platform powers full-stack applications for business users, including Playcode.ai.

For more information about our cloud platform, visit: https://playcode.io/cloud

sureglymop
This looks awesome! I really love the clean and minimalist website design too.

I've been excited about using (lib)krun as a drop in replacement for crun/runc for container engines, to make them run qemu microvms. I'm exploring what it could look like if every process of an OS ran like that. I envy you, would love to work on something like this!

gandreani
Hey this is amazing! I see the sqlite db is replicated but how does it handle multiple instances as writers? Curious if the underlying sqlite engine is syzy or if there's other restrictions to be aware of
dhchun1203
The warm-pool tree (kernel → base runtime → app) with CoW memory pages is a nice design — that's the part that makes 3ms believable rather than marketing.

Question on the shared SQLite: with multi-writer CRDT replication and eventual consistency, how do you handle operations that need global agreement — unique usernames at signup, or "did my vote count exactly once"? The HN-clone demo has both auth and voting, so I'm curious whether the HTML app model resolves those at the CRDT layer or accepts last-write-wins and tolerates the edge cases.

siliconc0w
Built in replicated database and filesystem is pretty rad. Fly leaves this as an exercise for the user.

You should license the backend to enterprises that want a cheaper/lighter weight option to kubernetes for the surge of agentically coded internal apps.

tomComb
> Billed per-second on actual resources consumed, … memory tracks active resident pages

Wait, are you saying it has dynamic vertical scaling of RAM?

maclockard
A replicated SQLite is very cool! One question I would have is why expose that as the storage instead of the platform providing a managed storage API? I guess I might be concerned about replication lag and complexity for consumers with the replicated SQLite.

Is it to have more sympathy for LLMs? More 1:1 with a local dev environment?