ADR 0083 proposed; 057/058 diagnosed and located

One push leaves the mesh consistent (the 057 decision, proposed for acceptance); the shared runtime waits for its broker (058). Fixes on mesh-control fix/one-push-is-enough and mesh-tools fix/the-runtime-waits-for-its-broker; the built-store-cross-node bed enforces both.
2026-09-18 02:10:01 +02:00
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commit 9fd7e6c458
6 changed files with 93 additions and 5 deletions
@@ -0,0 +1,52 @@
+---
+topic: the mesh
+status: proposed
+date: 2026-09-18
+deciders: jochen
+reconstructed: false
+extends: 0010-delivery.md
+---
+
+# 83. One push leaves the mesh consistent
+
+## Context
+
+A provision is minted while composing the *consumer's* node; the provider's grant list is a pure
+read of secrets already issued from it. So assigning a cross-node consumer and pushing its node
+produced a consumer that retried forever against a provider that had never heard of it, until the
+provider's node was pushed a second time — an action with no signal to take, documented nowhere,
+and invisible whenever consumer and provider share a machine
+([issue 057](../04-ISSUES/057-a-cross-node-consumer-is-provisioned-only-when-the-provider-is-pushed-again/00-report.md)).
+
+Two remedies were on the table: **cascade** — a push also delivers to the machines its compose
+changed — or **report** — a push says "now push the provider" and leaves the act to the operator.
+
+## Decision
+
+A push finishes what it starts: after composing and sending the named node, the controller
+recomputes what every machine should be, and any machine whose declaration changed *because of
+this push* is sent its declaration too — by name, in the push's own output, converging over a
+bounded number of rounds (a cascaded send may itself mint).
+
+"Changed because of this push" is a comparison, not a guess: the digest of what each machine
+should be is captured before the named compose and recomputed after. Machines that were already
+behind for unrelated reasons are not swept in — that remains `push --behind`, the explicit
+whole-mesh reconcile.
+
+Reporting alone was rejected because it converts a derived fact the controller already holds into
+an operator obligation, and an obligation enforced by nothing is issue 057 restated. The
+declaration is computed from the whole mesh; delivering a mesh that is knowingly inconsistent and
+merely saying so would make "push succeeded" mean less than it says.
+
+## Consequences
+
+- One push is sufficient for a cross-node consumer: the provider's grants arrive from the same
+  act that minted the provision. The undocumented rule "push the provider node too" ceases to
+  exist rather than becoming documentation.
+- A named push may deliver to machines the operator did not name. This is bounded to machines
+  whose declarations this push changed, and every one is named in the output — never silent.
+- The blast radius question from the issue is answered by the comparison: nothing is recomposed
+  into delivery except what the named compose provably changed.
+- How this is checked: the built-store-cross-node bed registers a cross-node consumer, pushes
+  only the consumer's node, and asserts the provider minted its vhost — the workaround push is
+  removed, so a regression fails the bed.
@@ -85,6 +85,7 @@ python3 00-META/checks/index.py            fail if stale
 - **0002** — [Nodes communicate over a message broker, not over HTTP](0002-nodes-communicate-over-a-broker.md)
 - **0003** — [An agent is a persistent employee, not an instance of a pool](0003-agents-are-persistent-employees.md)
 - **0077** — [The parts are named controller, foundation, node — not control plane, substrate, master](0077-the-controller-and-the-foundation.md)
+- **0083** — [One push leaves the mesh consistent](0083-one-push-leaves-the-mesh-consistent.md)  *(proposed)*

 ### Its tiers, from the bottom up

@@ -1,9 +1,10 @@
 ---
-status: open
+status: located
 opened: 2026-09-17
-located-in: []
+located-in:
+  - mesh-controller
 fixed-by:
-amended-design:
+amended-design: 02-DECISIONS/0083-one-push-leaves-the-mesh-consistent.md
 ---

 # 057 — A cross-node consumer is provisioned only when the provider is pushed again
@@ -0,0 +1,16 @@
+# Diagnosis — 2026-09-18
+
+The mechanism was already understood when the issue was opened: a provision secret is minted as a
+side-effect of composing the consumer's node, and the provider's grant list is a pure read of
+secrets already issued — so a provider composed before the consumer existed, and never again, is
+blind to it. The open question was the remedy: cascade the push, or report the obligation.
+
+Decided as [ADR 0083](../../02-DECISIONS/0083-one-push-leaves-the-mesh-consistent.md): a push
+finishes what it starts. The controller captures the digest of what every machine should be
+before composing the named node, recomputes after, and delivers to exactly the machines whose
+declaration changed because of this push — named in the output, bounded rounds, converging.
+Machines behind for unrelated reasons stay the business of `push --behind`.
+
+**Located in:** mesh-controller (the push command). Checked by the built-store-cross-node bed,
+which now pushes only the consumer's node and asserts the provider minted the vhost — the
+workaround push is removed, so a regression fails the bed.
@@ -1,7 +1,8 @@
 ---
-status: open
+status: located
 opened: 2026-09-17
-located-in: []
+located-in:
+  - mesh-tools
 fixed-by:
 amended-design:
 ---
@@ -0,0 +1,17 @@
+# Diagnosis — 2026-09-18
+
+1. The exit is the shared runtime's: serve mode connected the broker once and treated any failure
+   as fatal, so "the overlay tunnel came up a moment after the container" — the normal case on a
+   joined node — became an exit, a container-runtime restart, and a visible crash-loop.
+2. The failing step is the certificate pre-fetch that pins the broker (a 15s TLS probe), but the
+   shape is general: any reachability failure at startup had the same consequence.
+3. Answering the report's open questions: the shared runtime now retries the broker connection
+   in-process with capped backoff (2s doubling to 30s), aloud, indefinitely — "how long before it
+   is fatal" is answered *never*, because the failure modes that do not heal are not reachability:
+   a pinned-certificate mismatch still refuses immediately (an impostor does not become the
+   broker by being asked again), and configuration errors still exit at once. One-shot commands
+   (emit, invoke, run) still fail fast — a person is waiting.
+4. Checked by the built-store-cross-node bed: the joined consumer must report a container-runtime
+   restart count of zero.
+
+**Located in:** mesh-tools (the shared runtime's serve mode).