fix(cluster): /cluster/status reported a total partition on a healthy fleet

The status aggregator probed every peer's /cluster/status/local with NO
credential. That route is token-gated, so on any cluster with TIDAL_API_KEY set
each peer answered 401, and every peer row collapsed to the honest-unknown
placeholder: reachable false, partitioned true, applied_events null,
lag_events null, version "".

Only the OWN region survived, because it is served in-process with no HTTP hop.
The result: the one surface an operator reads to clear the N/N+1 version skew
before a rolling upgrade - and the deploy runbook's own step 4 - reported the
whole cluster partitioned while it was perfectly healthy, with every peer's
version blank so the skew check was blind.

Observed on the GKE cluster: all three pods answered /health 200 under leader
tidaldb-1, replication applied, and a curl between the exact same pod FQDNs
returned 200, while /cluster/status insisted both siblings were unreachable.

security::bearer_from_env documents this precise trap - a node that "dials an
authenticated peer with NO credential" - and count_alive_other_voters already
attaches the bearer. This forwards the CALLER's Authorization header instead of
reaching for creds.bearer(), matching the relayed-operator-hop convention that
/cluster/promote already uses, so a weakly-authenticated caller cannot borrow
the node's own credential to read peers it could not read directly.

Why it escaped: every other multi-process test runs with no TIDAL_API_KEY, where
a credential-less probe succeeds - including cluster_multiproc's all-reachable
assertion. The new test carries the key. Verified differential: it fails on the
reverted code with exactly the observed shape (us-east reachable, both peers
null/false/empty) and passes with the fix. cluster_multiproc still 5/5.

tidal-server/src/cluster/node.rs

@@ -6050,6 +6050,7 @@ pub struct AggregatedRegionStatus {
 #[allow(clippy::significant_drop_tightening)]
 pub async fn cluster_status(
     State(node): State<Arc<ClusterNode>>,
+    headers: HeaderMap,
 ) -> std::result::Result<Json<AggregatedStatusResponse>, ClusterAppError> {
     let state = node.replica_for(None)?;
     let leader_name = state.leader_name();
@@ -6059,9 +6060,24 @@ pub async fn cluster_status(
     // in-process (no HTTP hop); peers over the async client with the per-peer
     // budget. Each entry: (RegionId, name, Option<local-status-json>).
     let client = state.client.clone();
+    // A relayed operator hop: pass the caller's credential straight through, the
+    // same way `/cluster/promote` does. Without it every peer answers 401 and
+    // this aggregate reported `reachable: false`, `partitioned: true`,
+    // `applied_events: null` and `version: ""` for EVERY peer on an
+    // authenticated cluster — a total-partition reading taken off a perfectly
+    // healthy fleet, from the one surface an operator reads to clear the N/N+1
+    // version skew before a rolling upgrade (and the runbook's own deploy
+    // step 4). `security::bearer_from_env` documents this exact trap: "node then
+    // dials an authenticated peer with NO credential".
+    //
+    // FORWARDING the caller's header, rather than reaching for
+    // `creds.bearer()`, keeps a weakly-authenticated caller from borrowing this
+    // node's own credential to read peers it could not read directly.
+    let auth = forwarded_auth(&headers);
     let own_status = state.local_status().ok();
     let futures = regions.into_iter().map(|(rid, name, http)| {
         let client = client.clone();
+        let auth = auth.clone();
         let own_status = if rid == state.region {
             own_status.clone()
         } else {
@@ -6082,12 +6098,11 @@ pub async fn cluster_status(
                 return (rid, name, None); // unreachable: no declared addr
             };
             let url = peer_url(&http_addr, "/cluster/status/local");
-            let body = client
-                .get(&url)
-                .timeout(forward::STATUS_PEER_TIMEOUT)
-                .send()
-                .await
-                .ok();
+            let mut req = client.get(&url).timeout(forward::STATUS_PEER_TIMEOUT);
+            if let Some(auth) = auth {
+                req = req.header(axum::http::header::AUTHORIZATION, auth);
+            }
+            let body = req.send().await.ok();
             let json = match body {
                 Some(resp) if resp.status().is_success() => {
                     resp.json::<serde_json::Value>().await.ok()

tidal-server/tests/cluster_runbook.rs

@@ -1145,6 +1145,89 @@ fn runbook_auth_protected_routes_401_probes_open() {
     println!("[auth] protected routes 401 bare, probes + /openapi.json open, valid bearer 204");
 }
 
+/// The runbook's deploy step 4 — `GET /cluster/status | jq '.regions[] | {name,
+/// lag_events, reachable}'` — must tell the TRUTH on an authenticated cluster.
+///
+/// The aggregate probes every peer's `/cluster/status/local` over HTTP, and that
+/// route is token-gated (asserted by
+/// `runbook_auth_protected_routes_401_probes_open` above). A probe carrying no
+/// credential therefore reads 401 from every peer, and each peer row degrades to
+/// the "honest unknown": `reachable: false`, `partitioned: true`,
+/// `applied_events: null`, `version: ""`. The result is a TOTAL-PARTITION
+/// reading taken off a perfectly healthy fleet, on the one surface an operator
+/// reads to clear the N/N+1 version skew before a rolling upgrade.
+/// `security::bearer_from_env` documents this exact trap: a node that "dials an
+/// authenticated peer with NO credential".
+///
+/// Every OTHER multi-process test — including `cluster_multiproc`'s
+/// all-reachable assertion — runs with no `TIDAL_API_KEY`, where a
+/// credential-less probe succeeds. That is precisely why this was invisible for
+/// so long, so this test carries the key.
+#[test]
+fn runbook_cluster_status_aggregate_reaches_peers_under_auth() {
+    const KEY: &str = "runbook-status-aggregate-key";
+    let opts = (0..3).fold(ClusterOptions::new(3), |opts, i| {
+        opts.with_env(i, "TIDAL_API_KEY", KEY)
+    });
+    let cluster = MultiProcCluster::start_with(opts);
+
+    let status_url = format!("{}/cluster/status", cluster.node(LEADER));
+    let fetch = || -> serde_json::Value {
+        let resp = cluster
+            .client()
+            .get(&status_url)
+            .header("Authorization", format!("Bearer {KEY}"))
+            .send()
+            .expect("GET /cluster/status");
+        assert_eq!(
+            resp.status().as_u16(),
+            200,
+            "an operator read of /cluster/status must still serve with the bearer"
+        );
+        resp.json().expect("/cluster/status body is JSON")
+    };
+
+    // The fan-out gets the convergence budget to report every peer.
+    let deadline = Instant::now() + convergence_budget();
+    let settled = loop {
+        let snap = fetch();
+        let all_reachable = snap["regions"].as_array().is_some_and(|rows| {
+            rows.len() == 3 && rows.iter().all(|r| r["reachable"].as_bool() == Some(true))
+        });
+        if all_reachable {
+            break snap;
+        }
+        assert!(
+            Instant::now() < deadline,
+            "/cluster/status never reported all 3 regions reachable on an \
+             AUTHENTICATED cluster — a peer probe that carries no credential \
+             reads its 401 as `unreachable`. Last snapshot: {snap}"
+        );
+        std::thread::sleep(Duration::from_millis(250));
+    };
+
+    // Each peer row must carry REAL values, never the unreachable placeholder.
+    for row in settled["regions"].as_array().expect("regions array") {
+        let name = row["name"].as_str().unwrap_or("<unnamed>");
+        assert_eq!(
+            row["partitioned"].as_bool(),
+            Some(false),
+            "{name}: a reachable region is not partitioned"
+        );
+        assert!(
+            !row["applied_events"].is_null(),
+            "{name}: applied_events must be a known number, not the \
+             unreachable-peer null"
+        );
+        assert!(
+            !row["version"].as_str().unwrap_or_default().is_empty(),
+            "{name}: must report its build version — the pre-upgrade N/N+1 skew \
+             check reads this field, and an unreachable peer reports it empty"
+        );
+    }
+    println!("[auth] /cluster/status aggregated all 3 regions through the forwarded bearer");
+}
+
 // ── Auth: the admin key separates operator authority from data-plane access ────
 
 /// With BOTH `TIDAL_API_KEY` and `TIDAL_ADMIN_KEY` set, a data-plane bearer is