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Junctions

Junctions are where lines cross. Nobody owns a junction — that’s the point.

The Junction is HoBo’s most advanced primitive: the federation layer that connects Yards across clouds for hybrid and multi-cloud operation. Yards remain peers — there is no super-controller and no shared mutable state. The final edge of HoBo’s scope model is federation, not containment.

This is graduate-level wandering. Most apps live happily in one camp for a long time; many never need a second yard. If you’re just arriving, start with Getting started.

Early-stage: Junction authoring now ships the authoring and inference surface — junction(), connectivity-tier selection, the federated DNS plan, per-yard plan extraction, and the trust/policy/registry federation records. It’s a local derivation engine: each yard still realizes its own half, and the realization machinery lands with the multi-cloud stage (see the trail map).

Wiring a junction

import { junction } from "hobo/junctions";

import awsYard from "./yards/aws";
import azureYard from "./yards/azure";

export default junction("my-app", { yards: [awsYard, azureYard] });

Just the members — connectivity is inferred. The junction reads the member yards’ manifests and derives the cross-cloud connectivity plane (peering/tiering plus DNS), and each yard realizes its own half. Trust federation, signed policy packs, and signed registry bundles ride the same mechanism.

Rules junctions enforce

  • Peer yards only. A junction adds yards; it does not reach into them. Each yard keeps its own event log, its own control plane, its own blast radius.
  • No shared mutable state. What crosses a junction is signed, versioned artifacts — policy packs, registry bundles, trust roots — not live coordination.
  • Policy at the border. Data-residency, sovereignty, and egress rules attach at the junction scope: what may cross which border is an explicit, auditable decision.
  • The broker admin holds the keys. Junction governance is also where camp inference can be switched off: a junction broker admin can require explicit, approved camps, so placement stays a deliberate act instead of an inferred one. The lockdown is enforced by the Conductor, and no narrower policy can switch inference back on.

When to reach for a junction

  • Hybrid: a cloud yard federated with the yard running on your own metal.
  • Multi-cloud by policy: EU data in an EU yard, everything else wherever it’s cheapest.
  • Credit surfing: when your app’s cheapest home this quarter is on the cloud that just handed you startup credits — and next quarter it isn’t.
  • Exit insurance: the practical difference between “we could leave AWS” and “we have left AWS twice this year, briefly, and nobody noticed.”

Junctions and continuous migration

A junction is where the guiding principle gets its full range. Within one camp, migration means rebalancing resources; within a yard, moving between regions; across a junction, the Dispatcher weighs whole clouds against each other — price, credits, egress, residency, reliability — and proposes policy-gated moves across the border. The same plan → gate → converge loop as everything else. The map got bigger; the walking stayed the same.

Where junctions go next