fix(services): не балансировать сервис с одним IP

KPI и карточка показывают живой OK, а не гистерезис unknown; DNS по-прежнему ждёт повторные успехи.

Co-authored-by: Cursor <[email protected]>

apps/api/test/health-check.test.ts

@@ -436,4 +436,46 @@ describe("CNAME health mapped onto service IPs", () => {
     const view = await getView(db, service.id);
     expect(view.health_status).toBe("up");
   });
+
+  it("getView shows live OK over hysteresis unknown", async () => {
+    const { createMemoryDb, repos, runMigrations } = await import("@cfdm/db");
+    const { getView } = await import("../src/services/service-config-service.js");
+    const { db, sqlite } = createMemoryDb();
+    runMigrations(sqlite);
+
+    const domain = repos.createDomain(db, null, "rkns.top", "zone-id");
+    const service = repos.createService(db, "RW Panel", "rw-panel");
+    repos.replaceServiceIps(db, service.id, ["2.59.161.102"]);
+    const binding = repos.insertBinding(db, domain.id, service.id, "c", null);
+    repos.replaceBindingIpsWithMeta(db, binding.id, [
+      { ip: "2.59.161.102", weight: 1, priority: 1 },
+    ]);
+    repos.upsertIpHealthStatus(
+      db,
+      "binding",
+      binding.id,
+      "2.59.161.102",
+      "unknown",
+      63,
+      0,
+      null,
+      1,
+    );
+    repos.insertHealthProbeLog(db, {
+      scope: "binding",
+      refId: binding.id,
+      ip: "2.59.161.102",
+      provider: "local",
+      status: "up",
+      ok: true,
+      latencyMs: 63,
+      colo: null,
+      error: null,
+    });
+
+    const view = await getView(db, service.id);
+    expect(view.health_status).toBe("up");
+    expect(view.ip_health[0]?.status).toBe("up");
+    expect(view.ip_health[0]?.latency_ms).toBe(63);
+  });
 });

apps/api/test/lb-reconcile.test.ts

@@ -158,6 +158,34 @@ describe("resolveDesiredAIps", () => {
     ).toEqual(["1.1.1.1"]);
   });
 
+  it("does not drain when the service has only one unique IP", () => {
+    expect(
+      resolveDesiredAIps(
+        weightedConfig,
+        [row("1.1.1.1", { health: "down" })],
+        ["1.1.1.1", "1.1.1.1"],
+        0,
+        ["1.1.1.1"],
+      ),
+    ).toEqual(["1.1.1.1", "1.1.1.1"]);
+  });
+
+  it("does not apply overlay when service pool is a single IP", () => {
+    const rows = [
+      row("1.1.1.1", { health: "up" }),
+      row("2.2.2.2", { health: "down" }),
+    ];
+    expect(
+      resolveDesiredAIps(
+        weightedConfig,
+        rows,
+        ["1.1.1.1", "2.2.2.2"],
+        0,
+        ["1.1.1.1"],
+      ),
+    ).toEqual(["1.1.1.1", "2.2.2.2"]);
+  });
+
   it("applies weighted overlay on a shared pool", () => {
     const rows = [
       row("1.1.1.1", { weight: 1, health: "up" }),
@@ -170,6 +198,18 @@ describe("resolveDesiredAIps", () => {
 });
 
 describe("shouldRecordFailoverDnsDiff", () => {
+  it("skips duplicate listings of the same IP", () => {
+    expect(
+      shouldRecordFailoverDnsDiff({
+        configuredIps: ["1.1.1.1", "1.1.1.1"],
+        lbMode: "failover",
+        added: [],
+        removed: ["1.1.1.1"],
+        downIps: new Set(["1.1.1.1"]),
+      }),
+    ).toBe(false);
+  });
+
   it("skips dedicated extra-FQDN", () => {
     expect(
       shouldRecordFailoverDnsDiff({