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hq/03-DESIGN
jschoubben 2204b01909 Design the node lifecycle end to end
The host was described as a component and never as something that runs for
years on a machine somebody else also uses. 09 covers every state a machine can
be in and every transition between them.

Four states: unmanaged, hosted, enrolled, disconnected. Only the last two are
nodes, and they are the same node in two situations. `hosted` -- the host
installed but never told which mesh it belongs to -- had no name before and is
where a machine sits between the two adoption commands.

Things that were unclear and now are not:

The first node walks the same path in an unusual order: reconcile from the
bundle, the control plane it just raised issues a token, enrol against it. Its
specialness lasts two commands. A side effect worth having -- enrolment is
exercised on node one, rather than being written and first used on node two.

Enrolment reports profile and inventory BEFORE the control plane decides
anything. The profile is the input to that decision, not a diagnostic; the
control plane cannot decide what a machine should run without knowing what it
can run.

Rebooting mid-apply is safe by construction. The store records each resource
after it worked, so a host that dies half way through comes back and applies
the rest. The rule that stops the host lying about what it did also makes it
crash-safe.

Retiring splits in two. Graceful is a final empty declaration. A node that is
gone will reconcile its last declaration forever -- the honest consequence of
making disconnection ordinary. The answer is not to make the host expire but
that the node holds nothing that outlives revocation: every grant is a per-node
credential revoked at the provider. A lost node keeps running and stops being
able to reach anything. Said plainly rather than implying the mesh can switch a
machine off, which it cannot and should not.

Losing the store is quiet and permanent, so it gets its own section. The host
re-enrols and re-applies fine; what does not come back is removal, because
resources it no longer has a record of become unowned and sit there
indefinitely.

Also corrects 0057, which said the mesh must not upgrade the host at all. That
conflated two acts. Replacing the binary is safe -- Unix keeps the running
inode. Stopping the unit is not. So the host may apply a package naming itself,
and restarts by finishing its apply and exiting cleanly, letting the supervisor
start it on the new binary. It never asks the service manager to restart it.
That makes a fleet-wide host upgrade an ordinary declaration, which the first
draft gave up on.

0057 remains proposed.
2026-08-27 21:16:44 +02:00
..
2026-08-25 01:55:52 +02:00

03-DESIGN

The authoritative specification. Implementation is built against what is written here.

Two layers

Folder What it is
00-as-is/ The mesh that exists today. Shipped behaviour, described as it is — including behaviour nobody would choose again.
01-to-be/ The mesh being built toward. Every statement traceable to a record in 02-DECISIONS/.

They are never mixed. A statement about the future does not belong in an as-is document, and an as-is document is never edited to describe an intention.

When a to-be design ships, it does not move. Its as-is counterpart is written or updated, the to-be document's status becomes implemented, and both stand — one describing what runs, the other recording what was intended. Deleting the intention loses the reasoning, which is the expensive half.

Frontmatter

Every design document (not the READMEs) carries:

---
layer: as-is | to-be
status: designed | in-progress | implemented | abandoned
code: []                 # owning code repo(s), from 00-META/repos.md
updated: YYYY-MM-DD      # date of the last status change, not of text edits
decisions: []            # 02-DECISIONS/ records this document rests on
---

For an as-is document, status: implemented is the normal state — it describes something that runs — and code: names where that implementation lives.

Status changes when implementation state changes, never because design text was edited. An implemented claim must be defensible from the owning repository's main branch, not from intent. If it cannot be checked, it is in-progress.

Cross-cutting views are generated from this frontmatter by the hq-status skill and never written to disk.

What belongs here

Functional analysis, architectural description, and specification — prose and diagrams only, no code. A manifest field may be named; a manifest may not be pasted. A document enters the to-be layer only after the decision behind it is recorded in 02-DECISIONS/ and the research that produced it is closed.

Subfolders are encouraged where a layer grows enough to need them.