b2c1378fd3
Fixes the Microsoft.Contractions/write-good.ThereIs/alex.Condescending/ Microsoft.Auto errors vale flagged in CI (prose-lint-errors, required): contractions throughout, no sentences opening with 'There is', dropped the 'auto-mints' hyphenation and the 'easily' condescension flag, and renamed the credentials table's 'what it is' header to 'kind' (also flagged once styles were resynced). No technical claim or file:line citation changed. Same fix applied to the one new line in docs/README.md's pointer to this page.
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Credentials: current state, target state, and the rule between the two
Where secrets.md is a map of every file a swarm holds, this
page is the direction of travel: what the credential shape is today, what
it's on track to become, and the test a change has to pass to count as movement
toward it rather than away.
It's the thing a discussion should point at. When the migration
below is complete, this page supersedes the old credential docs — secrets.md
gets deleted and this file moves into its place. Until then the two coexist and
neither is wrong: that one says where a file is, this one says whether it should
be a file at all.
Two conventions carry over unchanged, because the target doesn't relax them.
A secret is a path, never a value. Every option carrying key material or a token takes a file path, because a literal in a nix expression lands in the nix store — world-readable and permanent. That rule survives the migration; what changes is how many paths there are.
Public material is a value. A certificate or a public nkey is handed to every client that connects, so the store is a fine place for it. Nothing below is about those.
Current state
Four credential families live in the swarm's secret store, plus the mTLS identity that opens it. That fifth row isn't a stored secret — it's the credential that can't be, being what authenticates the reader to the store.
| store path | kind | minter | writer | reader | renewal | persisted outside the store |
|---|---|---|---|---|---|---|
swarm/agents/<agent>/matrix/<account> |
one agent's matrix account credential | swarm-controller, via a caller-supplied bearer token or its own m.login.password (swarm-controller/src/matrix_account.rs:14-21) |
same unit, put_matrix_account's store.write call (swarm-controller/src/matrix_account.rs:189-197) |
hive-c0re's credential worker, under the hive's identity (hive-c0re/src/workers/credential.rs:33-64) |
NONE |
yes — hive-priv writes <agent-state>/matrix-token, 0600, chowned to the agent (hive-priv/src/main.rs:535-556) |
swarm/hives/<hive>/matrix/appservice-token |
the appservice token authenticating one hive's homeserver | swarm-secret-publisher.nix itself, head -c 32 /dev/urandom on the authelia host (nix/host-modules/swarm-secret-publisher.nix:271-278) |
same unit (nix/host-modules/swarm-secret-publisher.nix:288-289) |
swarm-bao-matrix-token.service on the hive (nix/host-modules/glue-matrix-bao-token.nix:159-167) |
NONE |
yes, twice — the publisher's own state copy (nix/host-modules/swarm-secret-publisher.nix:185) and the hive's token file, 0600 (nix/host-modules/glue-matrix-bao-token.nix:180-181) |
swarm/hives/<hive>/queue/agent |
the OIDC client id + secret agent containers present to the swarm queue | authelia, on first boot, into its own client-secret dir | swarm-secret-publish.service (nix/host-modules/swarm-secret-publisher.nix:222-225) |
swarm-bao-queue-agent.service on the hive (nix/host-modules/glue-queue-agent-credential.nix:187-197) |
NONE |
yes — secret 0600 and client_id 0644 under the hive's agent-credential dir (nix/host-modules/glue-queue-agent-credential.nix:218-224) |
swarm/services/<clientId>/oidc/client |
a swarm service's own OIDC client secret, one per service | authelia, on first boot | swarm-secret-publish.service (nix/host-modules/swarm-secret-publisher.nix:245-248) |
whichever host runs that service — swarm-bao-grafana-oidc.service (nix/host-modules/swarm-grafana.nix:565-684), the collector's twin (nix/host-modules/swarm-otel.nix:685-767) |
NONE |
yes — Grafana's 0400 host file (nix/host-modules/swarm-grafana.nix:678-682), the collector's 0400 file handed in by LoadCredential (nix/host-modules/swarm-otel.nix:764-768) |
| (not stored) the store's own mTLS leaves | the certificate a host presents to reach the store at all | swarm-bao-pki.service, self-signed, 10-year (nix/host-modules/glue-bao-tls.nix:114-149) |
n/a | every client reads its own leaf off disk via BAO_CLIENT_CERT (swarm-secret-client/src/client.rs:12-14) |
NONE — signed only when absent (nix/host-modules/glue-bao-tls.nix:128-149) |
always, by construction — it has no other form |
Four things in that table are uncomfortable, and they're the reason this page exists rather than a note in the margin of the old one.
Every stored secret is persisted as a plaintext file outside the store. All four, without exception. The appservice token is persisted twice: once in the publisher's own state directory on the authelia host, and again in the token file on the hive that reads it.
Nothing rotates. Every renewal cell reads NONE. No rotation path exists
for any of the four, and none for the mTLS leaves either — those are signed once
if absent and carry ten years of validity, and deleting the CA to reissue
invalidates every client certificate already trusting it.
No agent container has a store identity at all. Not one
BAO_ADDR or BAO_CLIENT_CERT exists anywhere under nix/agent-modules/. An agent
never talks to the store; the hive host reads on the agent's behalf and writes
a file into the container. That's the exact inverse of the target below.
The appservice token has a second, uncoordinated minter. hive-matrix.nix
keeps a local first-boot mint as a fallback for an unreachable store. Two
minters exist for one logical credential, on different hosts, with no agreement
between them — they can diverge, and the only thing that reconciles them is the
reader overwriting the local value on its next successful start.
One half of the target is already real: all four families are minted once and
read by an identity that logs in with a certificate, with no ambient trust
anywhere in the path. The cleanest examples are swarm-bao-queue-agent.service
and swarm-bao-grafana-oidc.service. What each of them then does is write the
fetched bytes to disk.
Two per-agent credential files — the forge token and the github token
(hive-priv/src/main.rs's write_forge_token/write_github_token) — are deliberately absent from the table.
They're operator-supplied and never pass through the store at all, so they're
not credentials this page governs. Their absence isn't an oversight.
Target state
⚠️ This section describes what the swarm is moving toward — not what exists today. Read the current-state table above for that. In particular, the first line below is the one most often misread as a statement of fact, so it's stated as a target twice.
Every host needs a store mTLS certificate. Everything else is done through
the store. That's the target. Today only the host running the store itself
mints its own leaves automatically — for itself, and pre-emptively for a controller and a
publisher that might be co-located. For every other host, swarm-bao.nix:529-531
says it outright: this is "the credential an operator places by hand." No
automated issuance path exists for an ordinary hive. The target is one
out-of-band credential per host and zero out-of-band credentials anywhere else;
the current state is one out-of-band credential per host plus every file in
the last column of the table above.
Agent containers get an mTLS certificate passed in from the hive, and pull their secrets themselves. The hive's job becomes handing the agent an identity, not handing it secrets. Today no agent has an identity of any kind and every agent secret arrives as a file the host wrote.
No store-provided secret is persisted. A value read from the store lives in the memory of the process that needs it and nowhere else — not in a state directory, not in a bind-mounted file, not in a systemd credential. Today every one of the four is persisted, and one of them twice.
Per secret, the docs specify minter, reader, and renewal strategy. Those
three columns are the contract. A secret whose renewal strategy is NONE is
allowed to exist only as an honest record of where the swarm is — it's not a
strategy, and a new secret doesn't get to write it.
Progressive enhancement
The rule has two halves, and the second is the one that makes the first survivable.
New functionality matches the target shape immediately. No legacy clause covers code that doesn't exist yet.
Existing functionality moves step by step — each individual step moving toward the target shape, never sideways and never away. A step doesn't have to finish the migration. It has to not undo it.
That's checkable, so check it. Apply these to a pull request that touches a credential:
| question | a yes means |
|---|---|
| Does it add a minter outside the swarm's existing mint path? | block for new functionality. For existing functionality, only if it removes one too. |
| Does it persist a store-provided secret to disk — a state directory, a bind mount, a rendered config? | block for new functionality. For existing functionality, only if the change removes a persisted copy elsewhere and nets out fewer. |
Does it add a credential whose renewal strategy is NONE? |
block for new functionality. State the strategy, even if it's "operator reissues and restarts the reader." |
| Does it read a secret on another principal's behalf and hand it over? | block for new functionality. The principal that needs the value authenticates for it. |
| Does it give a host or container an out-of-band credential that's not the store mTLS leaf? | block, both. One out-of-band credential per principal is the whole point of the store. |
| Does it change the minter, reader, or renewal of an existing credential? | The current-state table above is stale until updated in the same change. |
For existing functionality the questions aren't pass/fail — they're a direction check. A change that persists one fewer copy, or moves one reader from a host-written file to its own store read, is a step and lands. A change that leaves the count the same while moving the file somewhere tidier isn't a step; it's churn with a migration story attached.
When the last yes in the current-state table's final column becomes a no,
this page replaces secrets.md and the current-state section goes with it.