diff --git a/02-DECISIONS/0082-the-registry-is-reached-by-name-and-trusted-by-the-overlay.md b/02-DECISIONS/0082-the-registry-is-reached-by-name-and-trusted-by-the-overlay.md new file mode 100644 index 0000000..81366a6 --- /dev/null +++ b/02-DECISIONS/0082-the-registry-is-reached-by-name-and-trusted-by-the-overlay.md @@ -0,0 +1,84 @@ +--- +topic: building it +status: accepted +date: 2026-09-17 +deciders: jochen +reconstructed: false +extends: 0072-two-graphs-and-the-build-chain.md +--- + +# 82. The registry is reached by name, and the overlay is its security + +## Context + +Delivery ends at a node pulling an image, and for every node but the one that built it, that step +has never worked. Three facts conspired, each recorded separately: + +- Artifact references are written under `127.0.0.1:5000` — a deliberate parking (the catalogue + says so in the commit that reverted the mesh-reachable name: *"the runtime refused it: 'http: + server gave HTTP response to HTTPS client' … the binding expression returns then"*), so a joined + node is told to pull from its own loopback + ([issue 048](../04-ISSUES/048-nothing-makes-a-machine-trust-the-mesh-registry/00-report.md)). +- A container runtime treats any non-loopback registry as HTTPS, and the mesh's registry serves + plain HTTP; nothing the mesh writes tells any runtime otherwise — the one place that file + existed was the lab's, which is why this never failed in a bed (issue 048). +- Nothing gives a node an account for the registry + ([issue 042](../04-ISSUES/042-nothing-gives-a-node-an-account-for-a-registry/00-report.md)) — + and nothing has ever said whether one is required. + +The tempting fix is TLS from the mesh's own authority. The machinery even exists — the mesh CA +issues leaves for `.internal` names, and a `certificate:` manifest field delivers them. But +the registry is reached **over the overlay**, and the overlay is WireGuard: every byte is already +encrypted and already authenticated to a peer the mesh admitted. The mesh's own code has carried +this position for weeks: *"the registry is reached over the mesh's own private network … a second +layer inside it would be certificates to issue and rotate for no property the first does not +have."* TLS inside the tunnel would also re-order genesis (a certificate needs the network, the +registry precedes it) and put CA handling into three clients (the runtime, the archive fetcher, +the builder) — cost with no new property. + +## Decision + +**The overlay is the registry's transport security, and the mesh writes the trust it means.** + +1. **References name the registry by its mesh name.** The builder publishes to + `.internal:` (the binding's `at` and `port`) — the parked one-line change + lands. Genesis still publishes to loopback on the first machine, before any overlay exists; + references minted at genesis stay loopback and are valid where they matter — on that machine. + A rebuild re-pins to the mesh name. +2. **Every node on the private network is told the mesh's registry speaks plain HTTP.** The + controller injects, into every such node's declaration, a merged `/etc/docker/daemon.json` + naming `.internal:` under `insecure-registries`, and a service resource that + restarts the runtime when that file changes — the `/etc/hosts` pattern for the content, the + nftables pattern for the reload. No module author is involved; being on the network is what + grants the trust, because being on the network is what the trust *is*. +3. **No accounts (issue 042), recorded as the position it always was.** Reading and pushing + require presence on the overlay and nothing else. The boundary is enforced, not assumed: the + registry's `listens` is `from: mesh`, the firewall derives from it, and the overlay admits only + peers holding mesh-issued keys. An operator's *external* registry credential is an ordinary + operator-supplied secret (`secret accept`), owned by whichever module names that registry. + Per-node accounts return as a decision, not a patch, if the boundary assumption ever changes — + the shape would be the existing provision flow. + +## How this is checked + +- The no-fake lab bed: a joined node pulls a mesh-built image by the registry's `.internal` name + over the overlay — an address outside every range the lab's own runtime configuration trusts, + so the mesh-written trust is what makes it work or nothing does. +- The firewall half is generated from `listens` and visible in the node's ruleset (`from: mesh`). +- The plaintext-inside-tunnel position holds exactly as long as the registry is unreachable off + the overlay; the `listens` stanza and the derived ruleset are the check. + +## Consequences + +A runtime restart when the trust first lands on a node — at joining, before workloads, where it +is free. The registry's HTTP is exposed to whatever stands on the overlay, which is the stated +boundary; a mesh that wants defence in depth inside its own tunnel reopens this record rather +than bolting certificates on quietly. Issues 042 and 048 close on this record. + +## References + +- [issue 042](../04-ISSUES/042-nothing-gives-a-node-an-account-for-a-registry/00-report.md), + [issue 048](../04-ISSUES/048-nothing-makes-a-machine-trust-the-mesh-registry/00-report.md). +- [ADR 0072](0072-two-graphs-and-the-build-chain.md) — the build chain this completes. +- [ADR 0029](0029-a-network-is-a-shape-because-an-action-cannot-be-undone.md) — the overlay as a + boundary. diff --git a/02-DECISIONS/README.md b/02-DECISIONS/README.md index 0b0ed56..5a587cb 100644 --- a/02-DECISIONS/README.md +++ b/02-DECISIONS/README.md @@ -149,6 +149,7 @@ python3 00-META/checks/index.py fail if stale - **0068** — [The lab takes requests, one at a time, and runs each from its own copy](0068-the-lab-takes-requests.md) *(proposed)* - **0069** — [A module is a repository and a path within it](0069-a-module-is-a-repository-and-a-path.md) - **0076** — [The SDK is a published package, and the toolchain resolves it by version](0076-the-sdk-is-a-published-package.md) +- **0082** — [The registry is reached by name, and the overlay is its security](0082-the-registry-is-reached-by-name-and-trusted-by-the-overlay.md) ### How it is checked