part 4 附带：vm.boot/vm.create 500 记响应体

_boot_vm 只留 status 导致间歇 500 根因无法定位（两轮已提，
未改）。_api_call 的两个调用点现在都把响应体（截断到 500
字符单行）放进 ChvFailure 消息：vm_create_failed 与
vm_boot_failed 均含 status 与 body。body 是 VMM 的报错文本，
不含秘密；超长截断并标明。
新测试：test_wake_vm_boot_failed_records_body、
test_wake_vm_create_failed_records_body、
test_wake_vm_boot_failed_body_truncated。

cloud/tests/test_chv_closeup.py

@@ -213,6 +213,42 @@ class WakeFailureTest(CloseupCase):
         with self.assertRaises(ChvFailure) as ctx:
             ex.wake_vm(self._task())
         self.assertEqual(ctx.exception.kind, "vm_boot_failed")
+
+    def test_wake_vm_boot_failed_records_body(self):
+        # part 4：vm.boot 500 只留 status 即无法定位——body 要进
+        # 失败消息（截断后，见 _truncate_api_body）。
+        def api(socket_path, method, path, payload=None):
+            if method == "PUT" and path == "/vm.boot":
+                return (500, {"error": "boom-detail-500"})
+            return (200, {})
+        ex = self.make_exec(api_client=api)
+        with self.assertRaises(ChvFailure) as ctx:
+            ex.wake_vm(self._task())
+        self.assertEqual(ctx.exception.kind, "vm_boot_failed")
+        self.assertIn("boom-detail-500", str(ctx.exception))
+        self.assertIn("status=500", str(ctx.exception))
+
+    def test_wake_vm_create_failed_records_body(self):
+        def api(socket_path, method, path, payload=None):
+            if method == "PUT" and path == "/vm.create":
+                return (500, "No bootitem named default")
+            return (200, {})
+        ex = self.make_exec(api_client=api)
+        with self.assertRaises(ChvFailure) as ctx:
+            ex.wake_vm(self._task())
+        self.assertEqual(ctx.exception.kind, "vm_create_failed")
+        self.assertIn("No bootitem named default", str(ctx.exception))
+
+    def test_wake_vm_boot_failed_body_truncated(self):
+        def api(socket_path, method, path, payload=None):
+            if method == "PUT" and path == "/vm.boot":
+                return (500, {"error": "x" * 2000})
+            return (200, {})
+        ex = self.make_exec(api_client=api)
+        with self.assertRaises(ChvFailure) as ctx:
+            ex.wake_vm(self._task())
+        self.assertIn("已截断", str(ctx.exception))
+        self.assertLess(len(str(ctx.exception)), 1200)
         self.assertIn("vm_failed", self._audit_events())
         self.assertEqual(ex._vms, {})