feat: signed releases and a host-side updater for container nodes

CI signs the image digest of each agent and probe release; the panel only
stores and forwards it. Nodes write the manifest to their data directory and
a host updater verifies the signature with a local public key, pulls by
digest, restarts the unit and rolls back when it is unhealthy. The panel can
list releases, ask a node to update and show the reported update state.

.woodpecker/main-amd64-build.yml

@@ -36,6 +36,11 @@ steps:
       ZOT_USERNAME: justme
       ZOT_SECRET:
         from_secret: zot_secret
+      RELEASE_API_URL: https://mo.oeo.one
+      RELEASE_SIGNING_KEY:
+        from_secret: release_signing_key
+      RELEASE_API_TOKEN:
+        from_secret: release_api_token
     commands:
       - bash ci/build-main-amd64.sh agent
     depends_on: []
@@ -48,6 +53,11 @@ steps:
       ZOT_USERNAME: justme
       ZOT_SECRET:
         from_secret: zot_secret
+      RELEASE_API_URL: https://mo.oeo.one
+      RELEASE_SIGNING_KEY:
+        from_secret: release_signing_key
+      RELEASE_API_TOKEN:
+        from_secret: release_api_token
     commands:
       - bash ci/build-main-amd64.sh probe
     depends_on: []

backend/agent/src/Monitor.Agent/AgentApp.cs

@@ -25,6 +25,7 @@ public sealed class AgentApp : IDisposable
     private readonly TaskCompletionSource _ready = new(TaskCreationOptions.RunContinuationsAsynchronously);
     private readonly AgentAdmission _admission;
     private readonly Outbox _outbox = new(64 << 20);
+    private readonly UpdateBridge _update;
     private readonly BackendUplink _uplink;
     private readonly UdpMux _udp;
     private readonly TcpAcceptor _tcp;
@@ -34,8 +35,10 @@ public sealed class AgentApp : IDisposable
     private readonly TestRunner _tests;
     private readonly FleetLink _link;
 
-    public AgentApp(AgentConfig config, LoadedNodeIdentity identity, TimeProvider time, INodeLog log)
+    /// <param name="dataDirectory">配置目录（容器里的 <c>/etc/monitor</c>）：宿主机更新器和节点在这里交换清单、请求和状态。</param>
+    public AgentApp(AgentConfig config, LoadedNodeIdentity identity, string dataDirectory, TimeProvider time, INodeLog log)
     {
+        _update = new UpdateBridge(dataDirectory, new ConfigStore(dataDirectory).Write, log);
         _config = config;
         _identity = identity;
         _time = time;
@@ -200,6 +203,24 @@ public sealed class AgentApp : IDisposable
                 (_, cancel, _) => ValueTask.FromResult(Result<TestRunResult>.Ok(new TestRunResult { Accepted = _tests.Cancel(cancel.TestId) })));
         }
 
+        if (Allow(MonitorMethods.UpdateOffer))
+        {
+            router.OnNotify(MonitorMethods.UpdateOffer, MonitorJsonContext.Default.UpdateOfferParams, (_, offer, _) =>
+            {
+                _update.WriteOffer(offer);
+                return ValueTask.CompletedTask;
+            });
+        }
+
+        if (Allow(MonitorMethods.UpdateApply))
+        {
+            router.OnNotify(MonitorMethods.UpdateApply, MonitorJsonContext.Default.UpdateOfferParams, (_, _, _) =>
+            {
+                _update.RequestApply();
+                return ValueTask.CompletedTask;
+            });
+        }
+
         if (Allow(MonitorMethods.ProbeDisconnect))
         {
             router.On(
@@ -270,6 +291,7 @@ public sealed class AgentApp : IDisposable
             DroppedInvalid = _counters.DroppedInvalid,
             DroppedRateLimited = _counters.DroppedRateLimited,
             QueueBytes = _outbox.PendingBytes,
+            Update = _update.ReadStatus(),
         };
         _lastIn = packetsIn;
         _lastOut = packetsOut;

backend/agent/src/Monitor.Agent/Program.cs

@@ -35,7 +35,7 @@ catch (Exception ex) when (ex is IOException or InvalidDataException or InvalidO
 
 using (identity)
 {
-    using var app = new AgentApp(config, identity, time, log);
+    using var app = new AgentApp(config, identity, Path.GetDirectoryName(Path.GetFullPath(configPath))!, time, log);
     await ServiceShell.RunAsync(app.RunAsync, log);
 }
 

backend/openapi/v1.json

@@ -3696,7 +3696,7 @@
         "tags": [
           "admin-build"
         ],
-        "summary": "Version, tag, commit and build time of the backend and every agent and probe",
+        "summary": "Version, tag, commit, build time and update state of the backend and every agent and probe",
         "operationId": "build_info_get",
         "responses": {
           "200": {
@@ -3732,6 +3732,175 @@
         }
       }
     },
+    "/api/admin/releases": {
+      "get": {
+        "tags": [
+          "admin-build"
+        ],
+        "summary": "The latest signed release manifest of each component",
+        "operationId": "releases_list",
+        "responses": {
+          "200": {
+            "description": "OK",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/PageDtoOfReleaseDto"
+                }
+              }
+            }
+          },
+          "401": {
+            "description": "Unauthorized",
+            "content": {
+              "application/problem+json": {
+                "schema": {
+                  "$ref": "#/components/schemas/ProblemDto"
+                }
+              }
+            }
+          },
+          "403": {
+            "description": "Forbidden",
+            "content": {
+              "application/problem+json": {
+                "schema": {
+                  "$ref": "#/components/schemas/ProblemDto"
+                }
+              }
+            }
+          }
+        }
+      },
+      "post": {
+        "tags": [
+          "admin-build"
+        ],
+        "summary": "Register a CI-signed release manifest; online nodes get it right away (their updaters verify the signature)",
+        "operationId": "releases_publish",
+        "requestBody": {
+          "content": {
+            "application/json": {
+              "schema": {
+                "$ref": "#/components/schemas/PublishReleaseRequest"
+              }
+            }
+          },
+          "required": true
+        },
+        "responses": {
+          "201": {
+            "description": "Created",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/ReleaseDto"
+                }
+              }
+            }
+          },
+          "400": {
+            "description": "Bad Request",
+            "content": {
+              "application/problem+json": {
+                "schema": {
+                  "$ref": "#/components/schemas/ProblemDto"
+                }
+              }
+            }
+          },
+          "401": {
+            "description": "Unauthorized",
+            "content": {
+              "application/problem+json": {
+                "schema": {
+                  "$ref": "#/components/schemas/ProblemDto"
+                }
+              }
+            }
+          },
+          "403": {
+            "description": "Forbidden",
+            "content": {
+              "application/problem+json": {
+                "schema": {
+                  "$ref": "#/components/schemas/ProblemDto"
+                }
+              }
+            }
+          },
+          "409": {
+            "description": "Conflict",
+            "content": {
+              "application/problem+json": {
+                "schema": {
+                  "$ref": "#/components/schemas/ProblemDto"
+                }
+              }
+            }
+          }
+        }
+      }
+    },
+    "/api/admin/nodes/{id}/update": {
+      "post": {
+        "tags": [
+          "admin-build"
+        ],
+        "summary": "Ask an online agent or probe to install the release it has been offered",
+        "operationId": "nodes_update",
+        "parameters": [
+          {
+            "name": "id",
+            "in": "path",
+            "required": true,
+            "schema": {
+              "type": "string"
+            }
+          }
+        ],
+        "responses": {
+          "204": {
+            "description": "No Content",
+            "content": {
+              "application/json": {
+                "schema": { }
+              }
+            }
+          },
+          "401": {
+            "description": "Unauthorized",
+            "content": {
+              "application/problem+json": {
+                "schema": {
+                  "$ref": "#/components/schemas/ProblemDto"
+                }
+              }
+            }
+          },
+          "403": {
+            "description": "Forbidden",
+            "content": {
+              "application/problem+json": {
+                "schema": {
+                  "$ref": "#/components/schemas/ProblemDto"
+                }
+              }
+            }
+          },
+          "409": {
+            "description": "Conflict",
+            "content": {
+              "application/problem+json": {
+                "schema": {
+                  "$ref": "#/components/schemas/ProblemDto"
+                }
+              }
+            }
+          }
+        }
+      }
+    },
     "/healthz": {
       "get": {
         "tags": [
@@ -5540,6 +5709,16 @@
               "null",
               "string"
             ]
+          },
+          "update": {
+            "oneOf": [
+              {
+                "type": "null"
+              },
+              {
+                "$ref": "#/components/schemas/NodeUpdateDto"
+              }
+            ]
           }
         }
       },
@@ -5612,6 +5791,49 @@
           }
         }
       },
+      "NodeUpdateDto": {
+        "required": [
+          "state",
+          "current_digest",
+          "available_tag",
+          "available_version",
+          "error",
+          "at"
+        ],
+        "type": "object",
+        "properties": {
+          "state": {
+            "type": "string"
+          },
+          "current_digest": {
+            "type": [
+              "null",
+              "string"
+            ]
+          },
+          "available_tag": {
+            "type": [
+              "null",
+              "string"
+            ]
+          },
+          "available_version": {
+            "type": [
+              "null",
+              "string"
+            ]
+          },
+          "error": {
+            "type": [
+              "null",
+              "string"
+            ]
+          },
+          "at": {
+            "format": "date-time"
+          }
+        }
+      },
       "OverviewDto": {
         "required": [
           "range",
@@ -5989,6 +6211,27 @@
           }
         }
       },
+      "PageDtoOfReleaseDto": {
+        "required": [
+          "items",
+          "next_cursor"
+        ],
+        "type": "object",
+        "properties": {
+          "items": {
+            "type": "array",
+            "items": {
+              "$ref": "#/components/schemas/ReleaseDto"
+            }
+          },
+          "next_cursor": {
+            "type": [
+              "null",
+              "string"
+            ]
+          }
+        }
+      },
       "PageDtoOfSettingDto": {
         "required": [
           "items",
@@ -6432,6 +6675,27 @@
           }
         }
       },
+      "PublishReleaseRequest": {
+        "required": [
+          "manifest",
+          "signature"
+        ],
+        "type": "object",
+        "properties": {
+          "manifest": {
+            "type": [
+              "null",
+              "string"
+            ]
+          },
+          "signature": {
+            "type": [
+              "null",
+              "string"
+            ]
+          }
+        }
+      },
       "RawChunkMetaDto": {
         "required": [
           "chunk_id",
@@ -6573,6 +6837,38 @@
           }
         }
       },
+      "ReleaseDto": {
+        "required": [
+          "component",
+          "seq",
+          "tag",
+          "version",
+          "digest"
+        ],
+        "type": "object",
+        "properties": {
+          "component": {
+            "type": "string"
+          },
+          "seq": {
+            "pattern": "^-?(?:0|[1-9]\\d*)$",
+            "type": [
+              "integer",
+              "string"
+            ],
+            "format": "int64"
+          },
+          "tag": {
+            "type": "string"
+          },
+          "version": {
+            "type": "string"
+          },
+          "digest": {
+            "type": "string"
+          }
+        }
+      },
       "ScoreDto": {
         "required": [
           "score",

backend/probe/src/Monitor.Probe/ProbeApp.cs

@@ -31,6 +31,7 @@ public sealed class ProbeApp : IDisposable
         _env = new ConnectionEnv(identity, file.ProbeId, file.Limits, directory, new MonoClock(time), time, log);
         directory.Changed += () => _changed.Release();
 
+        var update = new UpdateBridge(configDirectory, new ConfigStore(configDirectory).Write, log);
         var options = new FleetLinkOptions
         {
             Server = new Uri(file.Server),
@@ -38,6 +39,7 @@ public sealed class ProbeApp : IDisposable
             NodeId = new NodeId(file.ProbeId),
             NodeVersion = Version,
             Capabilities = [MonitorCapabilities.Base],
+            HeartbeatExtra = () => JsonSerializer.SerializeToElement(new ProbeHeartbeatExtra { Update = update.ReadStatus() }, MonitorJsonContext.Default.ProbeHeartbeatExtra),
             HelloMeta = () => JsonSerializer.SerializeToElement(new ProbeHelloMeta { Platform = PlatformDetector.Detect() }, MonitorJsonContext.Default.ProbeHelloMeta),
         };
         var list = new StateHandler<ProbeAgentList>(
@@ -48,7 +50,18 @@ public sealed class ProbeApp : IDisposable
                 directory.Apply(doc);
                 return ValueTask.FromResult(new StateSyncResult { AppliedVersion = version });
             });
-        _link = new FleetLink(options, new RpcRouter<LinkContext>(), [list], new Outbox(1 << 20), time, log);
+        var router = new RpcRouter<LinkContext>()
+            .OnNotify(MonitorMethods.UpdateOffer, MonitorJsonContext.Default.UpdateOfferParams, (_, offer, _) =>
+            {
+                update.WriteOffer(offer);
+                return ValueTask.CompletedTask;
+            })
+            .OnNotify(MonitorMethods.UpdateApply, MonitorJsonContext.Default.UpdateOfferParams, (_, _, _) =>
+            {
+                update.RequestApply();
+                return ValueTask.CompletedTask;
+            });
+        _link = new FleetLink(options, router, [list], new Outbox(1 << 20), time, log);
     }
 
     /// <summary>到面板的连接（测试和状态查看用）。</summary>

backend/shared/Monitor.Measurement/Update/UpdateBridge.cs

@@ -0,0 +1,100 @@
+using System.Text;
+using System.Text.Json;
+using Fleet.Core;
+using Monitor.Protocol;
+
+namespace Monitor.Measurement;
+
+/// <summary>
+/// 节点进程和宿主机更新器之间的文件交换（容器里 <c>/etc/monitor</c>，也就是数据目录）：
+/// 节点把面板发来的清单和签名写进 <c>update/</c>，把「更新」请求写成 <c>update/apply.request</c>；更新器验签并更新，状态写在 root 拥有的 <c>update-status/status.json</c>。
+/// 节点进程不执行任何命令，也不信任清单的内容（验签在宿主机上）。没有安装更新器时目录写不了或没人读，调用只是返回 false。
+/// </summary>
+public sealed class UpdateBridge
+{
+    private const int MaxManifestBytes = 4096;
+    private const int MaxSignatureBytes = 512;
+    private const int MaxStatusBytes = 4096;
+
+    private readonly string _updateDirectory;
+    private readonly string _statusFile;
+    private readonly Action<string, byte[]> _write;
+    private readonly INodeLog _log;
+
+    /// <param name="write">写数据目录里的文件（相对路径，原子替换）：由节点传入 <c>ConfigStore.Write</c>——常驻进程里只有它可以写文件。</param>
+    public UpdateBridge(string dataDirectory, Action<string, byte[]> write, INodeLog log)
+    {
+        _updateDirectory = Path.Combine(dataDirectory, "update");
+        _statusFile = Path.Combine(dataDirectory, "update-status", "status.json");
+        _write = write;
+        _log = log;
+    }
+
+    /// <summary>放下面板发来的清单和签名（和已有的一样就不动，免得每次重连都惊动更新器）。先写清单、后写签名：更新器监视的是签名文件。</summary>
+    public bool WriteOffer(UpdateOfferParams offer)
+    {
+        byte[] manifest = Encoding.UTF8.GetBytes(offer.Manifest);
+        byte[] signature = Encoding.UTF8.GetBytes(offer.Signature);
+        if (manifest.Length is 0 or > MaxManifestBytes || signature.Length is 0 or > MaxSignatureBytes)
+        {
+            _log.Warn("ignoring an update offer of an unexpected size");
+            return false;
+        }
+
+        try
+        {
+            string manifestPath = Path.Combine(_updateDirectory, "offer.manifest");
+            string signaturePath = Path.Combine(_updateDirectory, "offer.sig");
+            if (Same(manifestPath, manifest) && Same(signaturePath, signature))
+            {
+                return true;
+            }
+
+            _write("update/offer.manifest", manifest);
+            _write("update/offer.sig", signature);
+            _log.Info("update offer received");
+            return true;
+        }
+        catch (Exception ex) when (ex is IOException or UnauthorizedAccessException)
+        {
+            _log.Warn("could not store the update offer (is the updater installed?)", ("err", ex.Message));
+            return false;
+        }
+    }
+
+    /// <summary>请求更新：写一个空的 <c>apply.request</c>（更新器验签通过、清单更新才会真的动手）。</summary>
+    public bool RequestApply()
+    {
+        try
+        {
+            _write("update/apply.request", []);
+            _log.Info("update requested");
+            return true;
+        }
+        catch (Exception ex) when (ex is IOException or UnauthorizedAccessException)
+        {
+            _log.Warn("could not request the update (is the updater installed?)", ("err", ex.Message));
+            return false;
+        }
+    }
+
+    /// <summary>更新器的状态；没有安装更新器、文件不存在或内容不对时返回 null。</summary>
+    public UpdateStatus? ReadStatus()
+    {
+        try
+        {
+            if (!File.Exists(_statusFile) || new FileInfo(_statusFile).Length > MaxStatusBytes)
+            {
+                return null;
+            }
+
+            return JsonSerializer.Deserialize(File.ReadAllBytes(_statusFile), MonitorJsonContext.Default.UpdateStatus);
+        }
+        catch (Exception ex) when (ex is IOException or UnauthorizedAccessException or JsonException)
+        {
+            return null;
+        }
+    }
+
+    private static bool Same(string path, byte[] content) => File.Exists(path) && File.ReadAllBytes(path).AsSpan().SequenceEqual(content);
+}

backend/shared/Monitor.Protocol/Rpc/MonitorRpc.cs

@@ -13,6 +13,8 @@ public static class MonitorMethods
     public const string TestStatus = "monitor.test.status";
     public const string Event = "monitor.event";
     public const string Host = "monitor.host";
+    public const string UpdateOffer = "monitor.update.offer";
+    public const string UpdateApply = "monitor.update.apply";
 
     // Probe ↔ Agent（点对点会话）
     public const string Clock = "monitor.clock";
@@ -217,6 +219,66 @@ public sealed class PlatformInfo
     public string? BuiltAt { get; set; }
 }
 
+/// <summary>
+/// 面板给节点的更新清单（<c>monitor.update.offer</c>）：<c>manifest</c> 是发布清单的原始文本，<c>signature</c> 是 base64 的签名。
+/// 节点只是把它们原样放进数据目录；验签、拉取、重启都由宿主机上的更新器完成（节点进程不执行任何命令，也不信任清单的内容）。
+/// </summary>
+public sealed class UpdateOfferParams
+{
+    [JsonPropertyName("manifest")]
+    public string Manifest { get; set; } = "";
+
+    [JsonPropertyName("signature")]
+    public string Signature { get; set; } = "";
+}
+
+/// <summary>宿主机更新器已经验证过的可用更新。</summary>
+public sealed class UpdateAvailable
+{
+    [JsonPropertyName("version")]
+    public string? Version { get; set; }
+
+    [JsonPropertyName("tag")]
+    public string? Tag { get; set; }
+
+    [JsonPropertyName("digest")]
+    public string? Digest { get; set; }
+
+    [JsonPropertyName("seq")]
+    public long Seq { get; set; }
+}
+
+/// <summary>
+/// 宿主机更新器的状态（它写在 <c>update-status/status.json</c>，节点读出来随心跳上报）：
+/// <c>up_to_date</c>、<c>available</c>、<c>applying</c>、<c>failed</c>、<c>rolled_back</c>、<c>invalid</c>（清单验签或校验没过）。
+/// 没有安装更新器的节点没有这个字段。
+/// </summary>
+public sealed class UpdateStatus
+{
+    [JsonPropertyName("state")]
+    public string State { get; set; } = "";
+
+    /// <summary>正在运行的镜像 digest（更新器记录的；还没更新过时为空）。</summary>
+    [JsonPropertyName("current")]
+    public string? Current { get; set; }
+
+    [JsonPropertyName("available")]
+    public UpdateAvailable? Available { get; set; }
+
+    [JsonPropertyName("error")]
+    public string? Error { get; set; }
+
+    [JsonPropertyName("at")]
+    public long At { get; set; }
+}
+
+/// <summary>Probe 的 <c>fleet.heartbeat</c> 附加字段：更新器的状态。</summary>
+public sealed class ProbeHeartbeatExtra
+{
+    [JsonPropertyName("update")]
+    public UpdateStatus? Update { get; set; }
+}
+
 /// <summary>Probe 的 <c>fleet.hello</c> 附加字段：系统、架构和构建信息（只用于展示和更新）。</summary>
 public sealed class ProbeHelloMeta
 {
@@ -326,6 +388,9 @@ public sealed class AgentHeartbeatExtra
 
     [JsonPropertyName("queue_bytes")]
     public long QueueBytes { get; set; }
+
+    [JsonPropertyName("update")]
+    public UpdateStatus? Update { get; set; }
 }
 
 /// <summary>Agent 下发给 Probe 的一条线路任务（期望状态类型 <c>line_task_set</c> 里的一项）。</summary>
@@ -465,6 +530,9 @@ public static class FragmentKeys
 [JsonSerializable(typeof(TestStatusParams))]
 [JsonSerializable(typeof(AgentEventParams))]
 [JsonSerializable(typeof(ProbeAgentList))]
+[JsonSerializable(typeof(UpdateOfferParams))]
+[JsonSerializable(typeof(UpdateStatus))]
+[JsonSerializable(typeof(ProbeHeartbeatExtra))]
 [JsonSerializable(typeof(ProbeHelloMeta))]
 [JsonSerializable(typeof(AgentEnrollMeta))]
 [JsonSerializable(typeof(PlatformInfo))]

backend/src/Monitor.Backend.Api/Admin/BuildEndpoints.cs

@@ -1,11 +1,13 @@
+using Fleet.Core;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Routing;
 using Monitor.Backend.Application;
+using Monitor.Protocol;
 
 namespace Monitor.Backend.Api;
 
-/// <summary>管理端的构建信息：后端自己和每个 Agent、Probe 的版本、tag、提交、构建时间（节点上报的，不含任何地址）。</summary>
+/// <summary>构建信息与更新：后端和每个节点的版本、tag、构建时间，CI 签名的发布清单，以及「更新这个节点」的请求。更新本身由节点宿主机上的更新器验签并执行。</summary>
 public static class BuildEndpoints
 {
     private const string Tag = "admin-build";
@@ -13,18 +15,44 @@ public static class BuildEndpoints
     public static void Map(RouteGroupBuilder group)
     {
         group.MapGet("/build-info", GetAsync)
-            .Api("build_info_get", "Version, tag, commit and build time of the backend and every agent and probe", Tag)
+            .Api("build_info_get", "Version, tag, commit, build time and update state of the backend and every agent and probe", Tag)
             .Returns<BuildInfoDto>().ProducesProblems(401, 403);
+        group.MapGet("/releases", ListReleasesAsync)
+            .Api("releases_list", "The latest signed release manifest of each component", Tag).Returns<PageDto<ReleaseDto>>().ProducesProblems(401, 403);
+        group.MapPost("/releases", PublishReleaseAsync)
+            .Api("releases_publish", "Register a CI-signed release manifest; online nodes get it right away (their updaters verify the signature)", Tag)
+            .Returns<ReleaseDto>(StatusCodes.Status201Created).ProducesProblems(400, 401, 403, 409);
+        group.MapPost("/nodes/{id}/update", RequestUpdateAsync)
+            .Api("nodes_update", "Ask an online agent or probe to install the release it has been offered", Tag).Returns<object>(StatusCodes.Status204NoContent).ProducesProblems(401, 403, 409);
     }
 
-    private static async Task<IResult> GetAsync(HttpContext http, NodeInfoService nodes, CancellationToken ct)
+    private static async Task<IResult> GetAsync(HttpContext http, NodeInfoService nodes, ReleaseService releases, CancellationToken ct)
     {
         var items = (await nodes.ListAsync(ct))
             .OrderBy(n => n.Kind, StringComparer.Ordinal)
             .ThenBy(n => n.NodeId, StringComparer.Ordinal)
-            .Select(n => new NodeBuildDto(n.NodeId, n.Kind, n.Os, n.OsName, n.Arch, n.Version, n.Tag, n.Commit, n.BuiltAt))
+            .Select(n => new NodeBuildDto(n.NodeId, n.Kind, n.Os, n.OsName, n.Arch, n.Version, n.Tag, n.Commit, n.BuiltAt, ToDto(releases.StatusOf(new NodeId(n.NodeId)))))
             .ToList();
         http.Response.Headers.CacheControl = "no-store";
         return TypedResults.Json(new BuildInfoDto(NodeEndpoints.Backend(withCommit: true), items), ApiJsonContext.Default.BuildInfoDto);
     }
+
+    private static async Task<IResult> ListReleasesAsync(ReleaseService releases, CancellationToken ct) =>
+        TypedResults.Json(new PageDto<ReleaseDto>([.. (await releases.ListAsync(ct)).Select(ToDto)], null), ApiJsonContext.Default.PageDtoReleaseDto);
+
+    private static async Task<IResult> PublishReleaseAsync(HttpContext http, ReleaseService releases, PublishReleaseRequest request)
+    {
+        Result<ReleaseOffer> result = await releases.PublishAsync(request.Manifest ?? "", request.Signature ?? "", http.RequestAborted);
+        return result.TryGet(out ReleaseOffer? offer, out FleetError? error)
+            ? TypedResults.Json(ToDto(offer), ApiJsonContext.Default.ReleaseDto, statusCode: StatusCodes.Status201Created)
+            : Problems.From(http, error);
+    }
+
+    private static async Task<IResult> RequestUpdateAsync(HttpContext http, ReleaseService releases, string id, CancellationToken ct) =>
+        await releases.RequestUpdateAsync(new NodeId(id), ct) ? TypedResults.NoContent() : Problems.Create(http, MonitorErrors.AgentOffline, "the node is not connected");
+
+    private static ReleaseDto ToDto(ReleaseOffer offer) => new(offer.Component, offer.Seq, offer.Tag, offer.Version, offer.Digest);
+
+    private static NodeUpdateDto? ToDto(UpdateStatus? status) =>
+        status is null ? null : new NodeUpdateDto(status.State, status.Current, status.Available?.Tag, status.Available?.Version, status.Error, status.At > 0 ? DateTimeOffset.FromUnixTimeSeconds(status.At) : null);
 }

backend/src/Monitor.Backend.Api/Contracts/AdminDtos.cs

@@ -124,6 +124,14 @@ public sealed record ChangePasswordRequest(string Password);
 public sealed record RecomputeDto(string State, IReadOnlyList<string> Metrics, long WindowsDone, long WindowsTotal, DateTimeOffset? From, DateTimeOffset? To, int QueueLength);
 
 /// <summary>管理端看的构建信息：每个节点自报的版本、tag、提交和构建时间，以及系统。</summary>
-public sealed record NodeBuildDto(string Id, string Kind, string? Os, string? OsName, string? Arch, string? Version, string? Tag, string? Commit, string? BuiltAt);
+public sealed record NodeBuildDto(string Id, string Kind, string? Os, string? OsName, string? Arch, string? Version, string? Tag, string? Commit, string? BuiltAt, NodeUpdateDto? Update = null);
+
+/// <summary>节点宿主机上的更新器报告的状态（<c>up_to_date</c>、<c>available</c>、<c>applying</c>、<c>failed</c>、<c>rolled_back</c>、<c>invalid</c>）；没装更新器的节点没有这个字段。</summary>
+public sealed record NodeUpdateDto(string State, string? CurrentDigest, string? AvailableTag, string? AvailableVersion, string? Error, DateTimeOffset? At);
+
+/// <summary>面板登记的最新发布清单（CI 签名的；验签在节点上）。</summary>
+public sealed record ReleaseDto(string Component, long Seq, string Tag, string Version, string Digest);
+
+public sealed record PublishReleaseRequest(string? Manifest, string? Signature);
 
 public sealed record BuildInfoDto(BuildDto Backend, IReadOnlyList<NodeBuildDto> Nodes);

backend/src/Monitor.Backend.Api/Contracts/ApiJsonContext.cs

@@ -38,6 +38,9 @@ namespace Monitor.Backend.Api;
 [JsonSerializable(typeof(PageDto<AgentDto>))]
 [JsonSerializable(typeof(AgentPatchRequest))]
 [JsonSerializable(typeof(BuildDto))]
+[JsonSerializable(typeof(ReleaseDto))]
+[JsonSerializable(typeof(PageDto<ReleaseDto>))]
+[JsonSerializable(typeof(PublishReleaseRequest))]
 [JsonSerializable(typeof(AboutDto))]
 [JsonSerializable(typeof(NodeBuildDto))]
 [JsonSerializable(typeof(BuildInfoDto))]

backend/src/Monitor.Backend.Application/Agents/MonitorFleetHooks.cs

@@ -52,9 +52,11 @@ public sealed class MonitorNodeEventSink : INodeEventSink
     private readonly LiveHub _live;
     private readonly AgentService _service;
     private readonly NodeInfoService _nodes;
+    private readonly ReleaseService _releases;
 
-    public MonitorNodeEventSink(IAgentStore agents, AgentRuntime runtime, IEventStore events, LiveHub live, AgentService service, NodeInfoService nodes)
+    public MonitorNodeEventSink(IAgentStore agents, AgentRuntime runtime, IEventStore events, LiveHub live, AgentService service, NodeInfoService nodes, ReleaseService releases)
     {
+        _releases = releases;
         _nodes = nodes;
         _agents = agents;
         _runtime = runtime;
@@ -80,6 +82,7 @@ public sealed class MonitorNodeEventSink : INodeEventSink
                 break;
             case NodeEventKind.Offline:
                 _runtime.MarkOffline(id);
+                _releases.RecordStatus(id, null);
                 _live.Publish(new NodeSignal("agent", id.Value, false, nodeEvent.AtMs));
                 await _events.AddAsync(id, "agent_offline", nodeEvent.AtMs, null, ct);
                 break;
@@ -93,6 +96,7 @@ public sealed class MonitorNodeEventSink : INodeEventSink
                     AgentHeartbeatExtra? beat = extra.Deserialize(MonitorJsonContext.Default.AgentHeartbeatExtra);
                     state.LastHeartbeat = beat;
                     state.LastHeartbeatAtMs = nodeEvent.AtMs;
+                    _releases.RecordStatus(id, beat?.Update);
                     if (beat is not null)
                     {
                         state.ReplaceProbes(beat.Probes.Select(p => new ConnectedProbeInfo(p.Id.Value, p.Version, p.Remote, p.SinceUtcMs)));
@@ -116,10 +120,12 @@ public sealed class MonitorNodeEventSink : INodeEventSink
     {
         switch (nodeEvent.Kind)
         {
-            case NodeEventKind.Online or NodeEventKind.Offline:
+            case NodeEventKind.Online:
-                _live.Publish(new NodeSignal("probe", id.Value, nodeEvent.Kind == NodeEventKind.Online, nodeEvent.AtMs));
+                _live.Publish(new NodeSignal("probe", id.Value, true, nodeEvent.AtMs));
                 break;
-            case NodeEventKind.Hello when nodeEvent.Hello?.Meta is { } raw:
+            case NodeEventKind.Hello:
+                if (nodeEvent.Hello?.Meta is { } raw)
+                {
                     try
                     {
                         ProbeHelloMeta? meta = raw.Deserialize(MonitorJsonContext.Default.ProbeHelloMeta);
@@ -129,6 +135,23 @@ public sealed class MonitorNodeEventSink : INodeEventSink
                     {
                         // 格式不对就忽略
                     }
+                }
+
+                await _releases.OfferToNodeAsync(id, ct);
+                break;
+            case NodeEventKind.Offline:
+                _live.Publish(new NodeSignal("probe", id.Value, false, nodeEvent.AtMs));
+                _releases.RecordStatus(id, null);
+                break;
+            case NodeEventKind.Heartbeat when nodeEvent.Extra is { } extra:
+                try
+                {
+                    _releases.RecordStatus(id, extra.Deserialize(MonitorJsonContext.Default.ProbeHeartbeatExtra)?.Update);
+                }
+                catch (JsonException)
+                {
+                    // 忽略格式不正确的附加字段
+                }
 
                 break;
         }
@@ -178,6 +201,7 @@ public sealed class MonitorNodeEventSink : INodeEventSink
         // 端口或证书指纹变了，Probe 需要新的列表
         AgentRecord? after = await _agents.GetAsync(id, ct);
         _nodes.ObserveAgentInBackground(id.Value, after?.PublicHost, meta.Platform);
+        await _releases.OfferToNodeAsync(id, ct);
         if (before is not null && after is not null
             && (!before.TlsSpki.AsSpan().SequenceEqual(after.TlsSpki) || before.ProbeTcpPort != after.ProbeTcpPort || !before.ProbeUdpPorts.SequenceEqual(after.ProbeUdpPorts))
             && after.Status == NodeStatus.Active)

backend/src/Monitor.Backend.Application/ApplicationServiceCollectionExtensions.cs

@@ -35,6 +35,7 @@ public static class ApplicationServiceCollectionExtensions
         services.AddSingleton<WindowComputer>();
         services.AddSingleton<AuthService>();
         services.AddSingleton<SettingsService>();
+        services.AddSingleton<ReleaseService>();
         services.AddSingleton<JoinTokenService>();
         services.AddSingleton<RawBrowserService>();
         services.AddSingleton<EventService>();

backend/src/Monitor.Backend.Application/Ports/IAgentGateway.cs

@@ -10,6 +10,9 @@ public interface IAgentGateway
 {
     IReadOnlyCollection<NodeId> OnlineAgents { get; }
 
+    /// <summary>所有在线的节点（Agent 和 Probe）。</summary>
+    IReadOnlyCollection<NodeId> OnlineNodes { get; }
+
     bool IsOnline(NodeId agent);
 
     /// <summary>某个 Agent 的期望状态变了：Gateway 重新计算并推送。</summary>
@@ -26,4 +29,10 @@ public interface IAgentGateway
     ValueTask<Result<bool>> DisconnectProbeAsync(NodeId agent, ProbeId probe, CancellationToken ct);
 
     ValueTask DisconnectAsync(NodeId agent, string reason, CancellationToken ct);
+
+    /// <summary>把发布清单和签名原样交给节点（通知，不等回复）。</summary>
+    ValueTask NotifyUpdateOfferAsync(NodeId node, string manifest, string signature, CancellationToken ct);
+
+    /// <summary>请求节点更新到它手里的清单。节点不在线返回 false。</summary>
+    ValueTask<bool> NotifyUpdateApplyAsync(NodeId node, CancellationToken ct);
 }

backend/src/Monitor.Backend.Application/Updates/ReleaseService.cs

@@ -0,0 +1,158 @@
+using System.Collections.Concurrent;
+using System.Diagnostics.CodeAnalysis;
+using System.Text.Json;
+using System.Text.RegularExpressions;
+using Fleet.Core;
+using Monitor.Protocol;
+
+namespace Monitor.Backend.Application;
+
+/// <summary>面板记下的、CI 签名的发布清单（只留每个组件最新的一份）。<c>Manifest</c> 是签名对象的原始文本，面板一个字节也不改。</summary>
+public sealed record ReleaseOffer(string Component, long Seq, string Tag, string Version, string Digest, string Manifest, string Signature);
+
+/// <summary>
+/// 发布清单的分发：CI 签名之后推给面板，面板存下来并原样转给在线的 Agent、Probe（节点连上时再补发一次）。
+/// <b>面板不验签、也不决定拉什么</b>：节点宿主机上的更新器用本机的发布公钥验签，并且只认本机配置的镜像仓库；
+/// 所以面板即使被攻破，也推不出一个能被装上的假镜像。面板只负责「通知」和「请求更新」，状态由节点随心跳报回来。
+/// </summary>
+public sealed partial class ReleaseService
+{
+    public const int MaxManifestBytes = 4096;
+    public const int MaxSignatureBytes = 512;
+    private static readonly string[] s_components = [NodeKinds.Agent, NodeKinds.Probe];
+
+    private readonly ISettingsStore _settings;
+    private readonly IAgentGateway _gateway;
+    private readonly ConcurrentDictionary<string, UpdateStatus> _status = new();
+
+    public ReleaseService(ISettingsStore settings, IAgentGateway gateway)
+    {
+        _settings = settings;
+        _gateway = gateway;
+    }
+
+    /// <summary>登记一份新清单并推给在线的同类节点。只要格式对、<c>seq</c> 比现有的新就收下（签名由节点验证）。</summary>
+    public async ValueTask<Result<ReleaseOffer>> PublishAsync(string manifest, string signature, CancellationToken ct)
+    {
+        if (!TryParse(manifest, signature, out ReleaseOffer? offer, out string? problem))
+        {
+            return ValidationError.Fail<ReleaseOffer>("manifest", problem);
+        }
+
+        ReleaseOffer? current = await GetAsync(offer.Component, ct);
+        if (current is not null && offer.Seq <= current.Seq)
+        {
+            return Result<ReleaseOffer>.Fail(MonitorErrors.NameConflict, $"a release with seq {current.Seq} or newer is already registered");
+        }
+
+        await _settings.SetAsync(Key(offer.Component, "manifest"), offer.Manifest, ct);
+        await _settings.SetAsync(Key(offer.Component, "signature"), offer.Signature, ct);
+        foreach (NodeId node in OnlineOf(offer.Component))
+        {
+            await _gateway.NotifyUpdateOfferAsync(node, offer.Manifest, offer.Signature, ct);
+        }
+
+        return Result<ReleaseOffer>.Ok(offer);
+    }
+
+    public async ValueTask<ReleaseOffer?> GetAsync(string component, CancellationToken ct)
+    {
+        string? manifest = await _settings.GetAsync(Key(component, "manifest"), ct);
+        string? signature = await _settings.GetAsync(Key(component, "signature"), ct);
+        return manifest is not null && signature is not null && TryParse(manifest, signature, out ReleaseOffer? offer, out _) && offer.Component == component ? offer : null;
+    }
+
+    public async ValueTask<IReadOnlyList<ReleaseOffer>> ListAsync(CancellationToken ct)
+    {
+        var list = new List<ReleaseOffer>();
+        foreach (string component in s_components)
+        {
+            if (await GetAsync(component, ct) is { } offer)
+            {
+                list.Add(offer);
+            }
+        }
+
+        return list;
+    }
+
+    /// <summary>节点刚连上：把它这个组件最新的清单补发一份（节点离线时发布的也不会错过）。</summary>
+    public async ValueTask OfferToNodeAsync(NodeId node, CancellationToken ct)
+    {
+        if (ComponentOf(node) is { } component && await GetAsync(component, ct) is { } offer)
+        {
+            await _gateway.NotifyUpdateOfferAsync(node, offer.Manifest, offer.Signature, ct);
+        }
+    }
+
+    /// <summary>请求某个节点更新到它手里那份（验过签的）清单。节点不在线返回 false。</summary>
+    public ValueTask<bool> RequestUpdateAsync(NodeId node, CancellationToken ct) => _gateway.NotifyUpdateApplyAsync(node, ct);
+
+    public void RecordStatus(NodeId node, UpdateStatus? status)
+    {
+        if (status is null)
+        {
+            _status.TryRemove(node.Value, out _);
+        }
+        else
+        {
+            _status[node.Value] = status;
+        }
+    }
+
+    public UpdateStatus? StatusOf(NodeId node) => _status.TryGetValue(node.Value, out UpdateStatus? status) ? status : null;
+
+    public void Forget(NodeId node) => _status.TryRemove(node.Value, out _);
+
+    private IEnumerable<NodeId> OnlineOf(string component) => _gateway.OnlineNodes.Where(n => ComponentOf(n) == component);
+
+    private static string? ComponentOf(NodeId node) =>
+        node.Value.StartsWith(AgentIds.Prefix, StringComparison.Ordinal) ? NodeKinds.Agent
+        : node.Value.StartsWith(ProbeId.Prefix, StringComparison.Ordinal) ? NodeKinds.Probe
+        : null;
+
+    private static string Key(string component, string part) => $"release.{component}.{part}";
+
+    private static bool TryParse(string manifest, string signature, [NotNullWhen(true)] out ReleaseOffer? offer, [NotNullWhen(false)] out string? problem)
+    {
+        offer = null;
+        problem = null;
+        if (manifest.Length is 0 or > MaxManifestBytes || signature.Length is 0 or > MaxSignatureBytes || !Base64().IsMatch(signature))
+        {
+            problem = "manifest or signature has an unexpected size or encoding";
+            return false;
+        }
+
+        try
+        {
+            using JsonDocument document = JsonDocument.Parse(manifest);
+            JsonElement root = document.RootElement;
+            string component = Text(root, "component");
+            string digest = Text(root, "digest");
+            if (root.ValueKind != JsonValueKind.Object || Array.IndexOf(s_components, component) < 0
+                || !root.TryGetProperty("seq", out JsonElement seq) || !seq.TryGetInt64(out long seqValue) || seqValue <= 0
+                || !Digest().IsMatch(digest) || Text(root, "image").Length is 0 or > 200)
+            {
+                problem = "manifest needs a known component, a positive seq, an image and a sha256 digest";
+                return false;
+            }
+
+            offer = new ReleaseOffer(component, seqValue, Text(root, "tag"), Text(root, "version"), digest, manifest, signature);
+            return true;
+        }
+        catch (JsonException)
+        {
+            problem = "manifest is not valid JSON";
+            return false;
+        }
+    }
+
+    private static string Text(JsonElement root, string name) =>
+        root.ValueKind == JsonValueKind.Object && root.TryGetProperty(name, out JsonElement value) && value.ValueKind == JsonValueKind.String ? value.GetString() ?? "" : "";
+
+    [GeneratedRegex("^[A-Za-z0-9+/=]+$")]
+    private static partial Regex Base64();
+
+    [GeneratedRegex("^sha256:[0-9a-f]{64}$")]
+    private static partial Regex Digest();
+}

backend/src/Monitor.Backend.Gateway/FleetGateway.cs

@@ -26,6 +26,8 @@ public sealed class FleetGateway : IAgentGateway
 
     public IReadOnlyCollection<NodeId> OnlineAgents => [.. Connections.OnlineNodes.Where(n => n.Value.StartsWith(AgentIds.Prefix, StringComparison.Ordinal))];
 
+    public IReadOnlyCollection<NodeId> OnlineNodes => Connections.OnlineNodes;
+
     public bool IsOnline(NodeId agent) => Connections.IsOnline(agent);
 
     public void NotifyTaskSetChanged(NodeId agent) => Notifier.NotifyChanged(agent);
@@ -61,4 +63,10 @@ public sealed class FleetGateway : IAgentGateway
     }
 
     public ValueTask DisconnectAsync(NodeId agent, string reason, CancellationToken ct) => Connections.DisconnectAsync(agent, reason, ct);
+
+    public async ValueTask NotifyUpdateOfferAsync(NodeId node, string manifest, string signature, CancellationToken ct) =>
+        await Connections.NotifyAsync(node, MonitorMethods.UpdateOffer, new UpdateOfferParams { Manifest = manifest, Signature = signature }, MonitorJsonContext.Default.UpdateOfferParams, ct);
+
+    public async ValueTask<bool> NotifyUpdateApplyAsync(NodeId node, CancellationToken ct) =>
+        await Connections.NotifyAsync(node, MonitorMethods.UpdateApply, new UpdateOfferParams(), MonitorJsonContext.Default.UpdateOfferParams, ct);
 }

backend/tests/Monitor.Backend.Tests/AgentHarness.cs

@@ -56,7 +56,7 @@ public sealed class AgentHarness : IAsyncDisposable
         };
         configure?.Invoke(config);
         LoadedNodeIdentity identity = LoadedNodeIdentity.Load(directory);
-        var app = new AgentApp(config, identity, TimeProvider.System, new ConsoleNodeLog(TimeProvider.System, Console.Out));
+        var app = new AgentApp(config, identity, directory, TimeProvider.System, new ConsoleNodeLog(TimeProvider.System, Console.Out));
         var harness = new AgentHarness(backend, directory, identity, app);
         await app.Ready.WaitAsync(TimeSpan.FromSeconds(10));
         await BackendFixture.EventuallyAsync(() => Task.FromResult(app.Link.IsConnected), because: "the agent should connect to the backend");

backend/tests/Monitor.Backend.Tests/UpdateTests.cs

@@ -0,0 +1,96 @@
+using System.Net;
+using System.Text.Json.Nodes;
+using Monitor.Protocol;
+using Monitor.TestSupport;
+
+namespace Monitor.Backend.Tests;
+
+[Collection("probe-e2e")]
+public sealed class UpdateTests
+{
+    private const string Digest = "sha256:0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef";
+
+    private readonly BackendFixture _backend;
+
+    public UpdateTests(BackendFixture backend)
+    {
+        _backend = backend;
+    }
+
+    // 面板不验签（节点宿主机上的更新器验），所以测试里签名随便写一个格式对的
+    private static string Manifest(string component, long seq, string digest = Digest) =>
+        $$"""{"schema":1,"component":"{{component}}","channel":"dev","image":"registry.example/monitor-dev/monitor-{{component}}","digest":"{{digest}}","tag":"dev-{{seq}}","version":"0.1.1","commit":"abc","built_at":"2026-10-06T00:00:00Z","seq":{{seq}}}""";
+
+    private async Task<HttpResponseMessage> PublishAsync(string manifest, string signature = "MEUCIQDc") =>
+        await _backend.Admin.PostAsync("/api/admin/releases", BackendFixture.Json(new JsonObject { ["manifest"] = manifest, ["signature"] = signature }));
+
+    [Fact]
+    public async Task Release_IsForwardedByteForByte_ToOnlineNodesOfThatComponent_AndToNodesThatConnectLater()
+    {
+        long seq = TimeProvider.System.GetUtcNow().ToUnixTimeSeconds() * 1000;
+        await using AgentSimulator online = await _backend.ConnectAgentAsync();
+        string manifest = Manifest("agent", seq);
+
+        using HttpResponseMessage published = await PublishAsync(manifest);
+        Assert.Equal(HttpStatusCode.Created, published.StatusCode);
+        JsonNode release = JsonNode.Parse(await published.Content.ReadAsStringAsync())!;
+        Assert.Equal("agent", release["component"]!.GetValue<string>());
+        Assert.Equal(Digest, release["digest"]!.GetValue<string>());
+
+        await BackendFixture.EventuallyAsync(() => Task.FromResult(online.UpdateOffers.ToArray().Any(o => o.Manifest == manifest && o.Signature == "MEUCIQDc")), because: "the offer reaches online agents unchanged");
+
+        // 之后才连上的节点，hello 之后补发
+        await using AgentSimulator late = await _backend.ConnectAgentAsync();
+        await BackendFixture.EventuallyAsync(() => Task.FromResult(late.UpdateOffers.ToArray().Any(o => o.Manifest == manifest)), because: "a node that connects later still gets the latest offer");
+
+        // 另一个组件（probe）的清单不会发给 Agent
+        using HttpResponseMessage probeRelease = await PublishAsync(Manifest("probe", seq));
+        Assert.Equal(HttpStatusCode.Created, probeRelease.StatusCode);
+        await Task.Delay(300);
+        Assert.DoesNotContain(online.UpdateOffers.ToArray(), o => o.Manifest.Contains("\"component\":\"probe\"", StringComparison.Ordinal));
+    }
+
+    [Fact]
+    public async Task Release_Registration_RefusesBadManifests_StaleSeq_AndNeedsAnAdmin()
+    {
+        long seq = TimeProvider.System.GetUtcNow().ToUnixTimeSeconds() * 1000 + 5;
+        Assert.Equal(HttpStatusCode.BadRequest, (await PublishAsync("{not json")).StatusCode);
+        Assert.Equal(HttpStatusCode.BadRequest, (await PublishAsync(Manifest("agent", seq, digest: "sha256:short"))).StatusCode);
+        Assert.Equal(HttpStatusCode.BadRequest, (await PublishAsync(Manifest("backend", seq))).StatusCode);
+        Assert.Equal(HttpStatusCode.BadRequest, (await PublishAsync(Manifest("agent", seq), signature: "not base64!")).StatusCode);
+
+        Assert.Equal(HttpStatusCode.Created, (await PublishAsync(Manifest("agent", seq))).StatusCode);
+        Assert.Equal(HttpStatusCode.Conflict, (await PublishAsync(Manifest("agent", seq))).StatusCode); // 同一个 seq：重放
+        Assert.Equal(HttpStatusCode.Conflict, (await PublishAsync(Manifest("agent", seq - 1))).StatusCode); // 更旧的 seq
+
+        using HttpResponseMessage anonymous = await _backend.Anonymous.PostAsync("/api/admin/releases", BackendFixture.Json(new JsonObject { ["manifest"] = Manifest("agent", seq + 1), ["signature"] = "MEUC" }));
+        Assert.Contains(anonymous.StatusCode, new[] { HttpStatusCode.Unauthorized, HttpStatusCode.Forbidden });
+    }
+
+    [Fact]
+    public async Task UpdateRequest_ReachesTheNode_AndItsReportedStatusShowsInBuildInfo()
+    {
+        await using AgentSimulator agent = await _backend.ConnectAgentAsync();
+        using HttpResponseMessage request = await _backend.Admin.PostAsync($"/api/admin/nodes/{agent.NodeId.Value}/update", null);
+        Assert.Equal(HttpStatusCode.NoContent, request.StatusCode);
+        await BackendFixture.EventuallyAsync(() => Task.FromResult(agent.UpdateApplies == 1));
+
+        // 节点（宿主机更新器）报告状态：面板在构建信息里显示
+        await agent.SendUpdateStatusAsync(new UpdateStatus { State = "available", Available = new UpdateAvailable { Tag = "dev-9", Version = "0.1.1", Digest = Digest, Seq = 9 }, At = TimeProvider.System.GetUtcNow().ToUnixTimeSeconds() });
+        await BackendFixture.EventuallyAsync(async () =>
+        {
+            JsonNode info = await _backend.GetJsonAsync(_backend.Admin, "/api/admin/build-info");
+            JsonNode? node = info["nodes"]!.AsArray().FirstOrDefault(n => n!["id"]!.GetValue<string>() == agent.NodeId.Value);
+            return node?["update"]?["state"]?.GetValue<string>() == "available" && node["update"]!["available_tag"]!.GetValue<string>() == "dev-9";
+        }, because: "the update state comes from the node's heartbeat");
+
+        // 节点离线之后不能请求更新
+        string id = agent.NodeId.Value;
+        await agent.DisposeAsync();
+        await BackendFixture.EventuallyAsync(async () =>
+        {
+            using HttpResponseMessage offline = await _backend.Admin.PostAsync($"/api/admin/nodes/{id}/update", null);
+            return offline.StatusCode == HttpStatusCode.Conflict || offline.StatusCode == HttpStatusCode.NotFound;
+        });
+    }
+}

backend/tests/Monitor.TestSupport/AgentSimulator.cs

@@ -48,6 +48,13 @@ public sealed class AgentSimulator : IAsyncDisposable
 
     public ConcurrentQueue<TestRunParams> TestRuns { get; } = new();
 
+    /// <summary>面板发来的发布清单（<c>monitor.update.offer</c>）和更新请求（<c>monitor.update.apply</c>）。</summary>
+    public ConcurrentQueue<UpdateOfferParams> UpdateOffers { get; } = new();
+
+    private int _updateApplies;
+
+    public int UpdateApplies => Volatile.Read(ref _updateApplies);
+
     public ConcurrentQueue<TestId> TestCancels { get; } = new();
 
     public IReadOnlyList<RejectedItem> RejectNextState { get; set; } = [];
@@ -188,6 +195,13 @@ public sealed class AgentSimulator : IAsyncDisposable
             new TestStatusParams { TestId = test, Status = status, Phase = phase, ErrorCode = errorCode },
             MonitorJsonContext.Default.TestStatusParams));
 
+    /// <summary>像节点的更新器报告的那样，随心跳上报更新状态。</summary>
+    public Task SendUpdateStatusAsync(UpdateStatus status) =>
+        SendAsync(RpcMessage.Notification(
+            FleetMethods.Heartbeat,
+            new HeartbeatParams { Extra = JsonSerializer.SerializeToElement(new AgentHeartbeatExtra { Update = status }, MonitorJsonContext.Default.AgentHeartbeatExtra) },
+            FleetRpcContext.Default.HeartbeatParams));
+
     public async Task<RpcMessage> RequestRawAsync(string method, JsonElement? parameters = null) => await RequestAsync(method, parameters);
 
     public async Task<TaskSet> WaitForTaskSetAsync(Func<TaskSet, bool> predicate, TimeSpan? timeout = null)
@@ -389,6 +403,12 @@ public sealed class AgentSimulator : IAsyncDisposable
             case FleetMethods.Revoked:
                 Revoked = true;
                 break;
+            case MonitorMethods.UpdateOffer:
+                UpdateOffers.Enqueue(message.Params!.Value.Deserialize(MonitorJsonContext.Default.UpdateOfferParams)!);
+                break;
+            case MonitorMethods.UpdateApply:
+                Interlocked.Increment(ref _updateApplies);
+                break;
             case MonitorMethods.TestRun:
                 TestRunParams run = message.Params!.Value.Deserialize(MonitorJsonContext.Default.TestRunParams)!;
                 TestRuns.Enqueue(run);

ci/build-main-amd64.sh

@@ -68,7 +68,7 @@ done
 for tag in latest "$dev_tag"; do
   pushed=false
   for attempt in 1 2 3; do
-    if buildah push --tls-verify=true "$local_image" "docker://$repository:$tag"; then
+    if buildah push --tls-verify=true --digestfile "$work/$component.digest" "$local_image" "docker://$repository:$tag"; then
       pushed=true
       break
     fi
@@ -80,3 +80,15 @@ for tag in latest "$dev_tag"; do
   [[ "$pushed" == true ]] || { echo "could not push $repository:$tag after 3 attempts" >&2; exit 1; }
   echo "pushed development image $repository:$tag"
 done
+
+# 发布清单：给镜像的 digest 签名（私钥只在 CI 密钥里），再登记到面板；面板把它原样转给在线的节点，节点宿主机上的更新器用本机的公钥验签后才会更新。
+# 没有配置签名密钥（例如 fork）就只构建镜像、不发清单。
+if [[ -n "${RELEASE_SIGNING_KEY:-}" ]]; then
+  digest="$(cat "$work/$component.digest")"
+  release_dir="$work/$component-release"
+  bash "$root/ci/release-manifest.sh" "$component" "$repository" "$digest" "$dev_tag" dev "$release_dir"
+  if [[ -n "${RELEASE_API_URL:-}" && -n "${RELEASE_API_TOKEN:-}" ]]; then
+    python3 -c 'import json,sys; print(json.dumps({"manifest": open(sys.argv[1]).read(), "signature": open(sys.argv[2]).read()}))'       "$release_dir/manifest.json" "$release_dir/manifest.sig"       | curl --fail-with-body --silent --show-error --retry 3 -X POST "${RELEASE_API_URL%/}/api/admin/releases"           -H "Authorization: Bearer $RELEASE_API_TOKEN" -H 'Content-Type: application/json' --data-binary @- >/dev/null
+    echo "registered the signed $component release with the panel"
+  fi
+fi

ci/release-manifest.sh

@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+# 生成并签名一个镜像的发布清单：ci/release-manifest.sh <组件> <镜像仓库> <digest> <tag> <通道> <输出目录>
+# 签名私钥从环境变量 RELEASE_SIGNING_KEY（PEM 内容）读取，只写进一个 600 权限的临时文件，用完即删；私钥只放在 CI 密钥里，不进仓库、不上传面板。
+# 输出：<输出目录>/manifest.json（扁平 JSON，签名对象是它的原始字节）和 manifest.sig（base64 的 DER ECDSA 签名）。
+set -euo pipefail
+
+component="${1:?usage: release-manifest.sh <component> <repository> <digest> <tag> <channel> <outdir>}"
+repository="${2:?}"; digest="${3:?}"; tag="${4:?}"; channel="${5:?}"; outdir="${6:?}"
+[[ "$component" =~ ^(agent|probe|backend)$ ]] || { echo "unsupported component: $component" >&2; exit 2; }
+[[ "$digest" =~ ^sha256:[0-9a-f]{64}$ ]] || { echo "digest must look like sha256:<64 hex>" >&2; exit 2; }
+[[ "$repository" =~ ^[a-z0-9./_-]+$ && "$tag" =~ ^[A-Za-z0-9._-]+$ && "$channel" =~ ^[a-z0-9._-]+$ ]] || { echo "unexpected characters in repository, tag or channel" >&2; exit 2; }
+[[ -n "${RELEASE_SIGNING_KEY:-}" ]] || { echo "RELEASE_SIGNING_KEY is required" >&2; exit 2; }
+
+root="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+version="$(sed -n 's#.*<Version>\(.*\)</Version>.*#\1#p' "$root/backend/Directory.Build.props" | head -1)"
+commit="$(git -C "$root" rev-parse --short=10 HEAD 2>/dev/null || true)"
+built_at="$(date -u +%Y-%m-%dT%H:%M:%SZ)"
+seq="$(date +%s)"
+
+mkdir -p "$outdir"
+printf '{"schema":1,"component":"%s","channel":"%s","image":"%s","digest":"%s","tag":"%s","version":"%s","commit":"%s","built_at":"%s","seq":%s}' \
+  "$component" "$channel" "$repository" "$digest" "$tag" "$version" "$commit" "$built_at" "$seq" > "$outdir/manifest.json"
+
+key="$(mktemp)"
+trap 'rm -f "$key" "$outdir/manifest.sig.bin"' EXIT
+chmod 600 "$key"
+printf '%s\n' "$RELEASE_SIGNING_KEY" > "$key"
+openssl dgst -sha256 -sign "$key" -out "$outdir/manifest.sig.bin" "$outdir/manifest.json"
+base64 -w0 "$outdir/manifest.sig.bin" > "$outdir/manifest.sig" 2>/dev/null || base64 "$outdir/manifest.sig.bin" | tr -d '\n' > "$outdir/manifest.sig"
+echo "signed $component $tag ($digest) seq=$seq"

docs/api.md

@@ -135,7 +135,9 @@
 | POST | `/api/admin/releases/{app}/{channel}/rollout` | `{version, batches:[{labels?, count?}], soak_minutes}`：分批灰度；只能选择已经签名的清单 |
 | POST | `/api/admin/releases/{app}/approve` | 对 `policy = notify` 的节点批准更新 `{version, agents?}` |
 | GET/PATCH | `/api/admin/settings` | 站点公开或私有、是否对访客显示构建信息（`site.show_build`）、保留期等 |
-| GET | `/api/admin/build-info` | 后端和每个 Agent、Probe 的版本、tag、提交、构建时间、系统（管理端「系统 → 版本」） |
+| GET | `/api/admin/build-info` | 后端和每个 Agent、Probe 的版本、tag、提交、构建时间、系统，以及节点宿主机更新器报告的更新状态（管理端「系统 → 版本」） |
+| GET/POST | `/api/admin/releases` | CI 签名的发布清单：POST 登记（`{manifest, signature}`，面板不验签、原样转给在线的节点和之后连上的节点），GET 看每个组件最新的一份 |
+| POST | `/api/admin/nodes/{id}/update` | 请求一个在线的 Agent 或 Probe 更新到它收到的清单（节点不在线返回 409） |
 | GET/POST/PATCH | `/api/admin/users` | 首次启动时通过命令行或环境变量创建初始管理员 |
 
 任务的请求体示例：

docs/deployment.md

@@ -194,3 +194,27 @@ OpenWrt 默认不带 OpenSSL：`opkg install libopenssl3`（较新的快照和 2
 | Agent 主机状态 | CPU 1.5%，内存 274 / 493 MB，已运行约 20.5 天 |
 
 这次试跑发现并修掉的问题：`hy2_ladder` 的阶梯按「块」而不是按「阶段」计算，真实的 Probe 把一个阶段切成几块，4 个阶段出了 7 步（模拟数据不切块，所以之前的测试没有发现）；现在同一阶段的块先合并。␍
+
+## 容器节点的更新（Agent、Probe）
+
+面板通知、节点验签、宿主机更新，**面板即使被攻破也装不上假镜像**：
+
+```text
+CI 构建并推镜像（Zot）──► ci/release-manifest.sh：对镜像 digest 的清单签名（ECDSA P-256，私钥只在 Woodpecker 密钥 release_signing_key 里）
+        └─ POST /api/admin/releases ──► 面板：只存下并原样转发（不验签）──► 在线的 Agent、Probe（连上时补发）
+                                            节点进程：只把清单和签名写进数据目录的 update/，不执行任何命令
+                                                 │ systemd.path 监视到 offer.sig
+                                                 ▼
+          宿主机 monitor-update（root）：复制到临时目录 → 用本机的发布公钥验签 → 核对组件和镜像仓库 → seq 必须比已安装的大
+                 → status：available / invalid（写进 update-status/，节点随心跳报给面板，管理端「版本」页显示）
+                 → 管理员点「更新」（或本机配置 POLICY=auto）→ podman pull <仓库>@sha256:<digest>（内容寻址，Registry 或链路上换不了）
+                 → 写 IMAGE=… 到 /etc/monitor-update/<组件>.image，重启容器单元；20 秒内没有健康就换回旧镜像（rolled_back）
+```
+
+- **安装更新器**（每个容器节点一次，root）：`packaging/update/install-updater.sh agent --data-dir /opt/monitor/etc --image-repo registry.oeo.one/monitor/monitor-agent --unit monitor-agent-container.service [--policy auto] [--authfile <Registry 认证文件>]`。它装好 `monitor-update` 脚本和发布公钥，写 `/etc/monitor-update/<组件>.conf`，启用两个 systemd 路径单元。容器单元要用 `EnvironmentFile=/etc/monitor-update/<组件>.image` 和 `${IMAGE}` 启动容器。
+- **镜像仓库、服务名、公钥都在本机配置里**，清单里写什么都不会改变拉取哪个仓库；清单被篡改、签名对不上、组件或仓库不符、`seq` 不比已安装的大（重放旧清单），都会被拒绝，状态是 `invalid`。
+- **业务进程不能改二进制，也不执行命令**：它只能往 `update/` 里放清单和请求；状态在 root 拥有的 `update-status/` 里（只读）。
+- **CI 的配置**：Woodpecker 密钥 `release_signing_key`（发布私钥，PEM）、`release_api_token`（面板的 API 令牌，管理员权限，用来登记清单）；环境变量 `RELEASE_API_URL`（面板地址）。没有 `release_signing_key` 就只构建镜像、不发清单。
+- **发布公钥**在 `packaging/update/release-key.pub.pem`；私钥不入库，请离线备份。更换密钥：节点上换新公钥之后再用新私钥发布。
+- 纯二进制的安装方式（`fleet-updater`、`fleet-release`，见 [fleet/update.md](fleet/update.md)）还没有实现；容器方式优先。
+

docs/fleet/update.md

@@ -1,5 +1,7 @@
 # Fleet：通用更新（Fleet.Update / fleet-updater）
 
+> **实现状态**：容器节点（Agent、Probe）的更新已经实现，见 [deployment.md](../deployment.md) 的「容器节点的更新」：同样的信任模型（离线发布密钥签名、本机配置公钥和仓库、`seq` 防重放、面板只通知和请求），清单里是镜像 digest，更新器是宿主机上的 `monitor-update`。本文下面描述的纯二进制方案（`Fleet.Update`、`fleet-updater`、`fleet-release`、健康信标）还没有实现。
+
 ## 1. 原则
 
 - **与产品无关**：`fleet-updater` 通过本地配置声明它管理哪些应用，一台机器上可以同时管理多个产品。

packaging/update/install-updater.sh

@@ -0,0 +1,89 @@
+#!/bin/sh
+# 在容器节点的宿主机上安装更新器：
+#   install-updater.sh <agent|probe> --data-dir <挂载到容器 /etc/monitor 的宿主机目录> --image-repo <镜像仓库，不带 tag> --unit <容器的 systemd 单元名>
+#                      [--policy auto|manual] [--authfile <拉镜像用的 Registry 认证文件>]
+# 需要 root、systemd、podman、openssl。做的事：装脚本和发布公钥，写本机配置，装两个 systemd 单元（有新清单就检查，有「更新」请求就更新）。
+# 容器的单元要从 EnvironmentFile=/etc/monitor-update/<组件>.image 读 IMAGE=…，并用 ${IMAGE} 启动容器（没有这个文件时先写一份当前镜像）。
+set -eu
+
+COMPONENT="${1:-}"; shift || true
+case "$COMPONENT" in agent|probe) ;; *) echo "usage: install-updater.sh <agent|probe> --data-dir D --image-repo R --unit U [--policy auto|manual] [--authfile F]" >&2; exit 2 ;; esac
+DATA_DIR=""; IMAGE_REPO=""; UNIT=""; POLICY="manual"; AUTHFILE=""
+while [ $# -gt 0 ]; do
+  case "$1" in
+    --data-dir) DATA_DIR="$2"; shift 2 ;;
+    --image-repo) IMAGE_REPO="$2"; shift 2 ;;
+    --unit) UNIT="$2"; shift 2 ;;
+    --policy) POLICY="$2"; shift 2 ;;
+    --authfile) AUTHFILE="$2"; shift 2 ;;
+    *) echo "unknown option: $1" >&2; exit 2 ;;
+  esac
+done
+[ -n "$DATA_DIR" ] && [ -n "$IMAGE_REPO" ] && [ -n "$UNIT" ] || { echo "--data-dir, --image-repo and --unit are required" >&2; exit 2; }
+case "$POLICY" in auto|manual) ;; *) echo "--policy must be auto or manual" >&2; exit 2 ;; esac
+[ "$(id -u)" -eq 0 ] || { echo "run as root" >&2; exit 1; }
+
+HERE="$(cd "$(dirname "$0")" && pwd)"
+install -d -m 755 /etc/monitor-update /var/lib/monitor-update
+install -m 755 "$HERE/monitor-update.sh" /usr/local/sbin/monitor-update
+install -m 644 "$HERE/release-key.pub.pem" /etc/monitor-update/release-key.pub.pem
+
+# 容器用户（UID 1654）能写 update/（放清单和请求）；update-status/ 归 root，业务进程只读
+install -d -m 755 -o 1654 -g 1654 "$DATA_DIR/update"
+install -d -m 755 "$DATA_DIR/update-status"
+
+cat > "/etc/monitor-update/$COMPONENT.conf" <<CONF
+DATA_DIR=$DATA_DIR
+IMAGE_REPO=$IMAGE_REPO
+UNIT=$UNIT
+PUBKEY=/etc/monitor-update/release-key.pub.pem
+ENV_FILE=/etc/monitor-update/$COMPONENT.image
+STATE_DIR=/var/lib/monitor-update
+POLICY=$POLICY
+AUTHFILE=$AUTHFILE
+CONF
+chmod 644 "/etc/monitor-update/$COMPONENT.conf"
+
+cat > "/etc/systemd/system/monitor-update-check-$COMPONENT.service" <<UNITFILE
+[Unit]
+Description=Check the signed update offer for monitor-$COMPONENT
+
+[Service]
+Type=oneshot
+ExecStart=/usr/local/sbin/monitor-update check $COMPONENT
+UNITFILE
+cat > "/etc/systemd/system/monitor-update-apply-$COMPONENT.service" <<UNITFILE
+[Unit]
+Description=Apply the verified update for monitor-$COMPONENT
+
+[Service]
+Type=oneshot
+TimeoutStartSec=300
+ExecStart=/usr/local/sbin/monitor-update apply $COMPONENT
+UNITFILE
+cat > "/etc/systemd/system/monitor-update-check-$COMPONENT.path" <<UNITFILE
+[Unit]
+Description=Watch for a new update offer for monitor-$COMPONENT
+
+[Path]
+PathChanged=$DATA_DIR/update/offer.sig
+Unit=monitor-update-check-$COMPONENT.service
+
+[Install]
+WantedBy=multi-user.target
+UNITFILE
+cat > "/etc/systemd/system/monitor-update-apply-$COMPONENT.path" <<UNITFILE
+[Unit]
+Description=Watch for an update request for monitor-$COMPONENT
+
+[Path]
+PathChanged=$DATA_DIR/update/apply.request
+Unit=monitor-update-apply-$COMPONENT.service
+
+[Install]
+WantedBy=multi-user.target
+UNITFILE
+
+systemctl daemon-reload
+systemctl enable --now "monitor-update-check-$COMPONENT.path" "monitor-update-apply-$COMPONENT.path"
+echo "updater installed for $COMPONENT (policy: $POLICY)"

packaging/update/monitor-update.sh

@@ -0,0 +1,142 @@
+#!/bin/sh
+# Monitor 容器节点（Agent、Probe）的宿主机更新器。用法：monitor-update <check|apply> <组件>   组件 = agent 或 probe
+#
+# 信任模型（防篡改、防中间人）：
+#   - 只接受用发布私钥签名的清单（ECDSA P-256 / SHA-256，对清单文件的原始字节签名）；公钥放在本机，面板和 Registry 都改不了它。
+#   - 清单里写的是镜像的 digest：拉取时用 repo@sha256:…，内容寻址，Registry 或链路上的人换不出另一个镜像。
+#   - 镜像仓库、组件、服务名都来自本机的配置（/etc/monitor-update/<组件>.conf），清单里写什么都不会改变拉哪个仓库。
+#   - 清单的 seq 必须比已安装的大（防止旧清单被重放回滚）。
+#   - 业务进程（Agent、Probe）只能往数据目录里写「清单」和「请求」文件，更新由这个宿主机脚本完成，业务进程不执行任何命令。
+set -eu
+
+CMD="${1:-}"
+COMPONENT="${2:-}"
+case "$CMD" in check|apply) ;; *) echo "usage: monitor-update <check|apply> <agent|probe>" >&2; exit 2 ;; esac
+case "$COMPONENT" in agent|probe) ;; *) echo "component must be agent or probe" >&2; exit 2 ;; esac
+
+CONF="${MONITOR_UPDATE_CONF_DIR:-/etc/monitor-update}/$COMPONENT.conf"
+[ -r "$CONF" ] || { echo "missing $CONF" >&2; exit 2; }
+# 配置：DATA_DIR（容器里 /etc/monitor 对应的宿主机目录）、IMAGE_REPO、UNIT、PUBKEY、POLICY（auto|manual）、AUTHFILE（可选）、
+#       STATE_DIR（已安装版本的记录）、ENV_FILE（容器单元读取的 IMAGE=… 文件）
+# shellcheck disable=SC1090
+. "$CONF"
+: "${DATA_DIR:?}" "${IMAGE_REPO:?}" "${UNIT:?}" "${PUBKEY:?}" "${ENV_FILE:?}"
+POLICY="${POLICY:-manual}"
+STATE_DIR="${STATE_DIR:-/var/lib/monitor-update}"
+# 业务进程（容器里的 Agent、Probe）可写的目录只有 update/：它在里面放 offer.manifest、offer.sig、apply.request。
+# 这个脚本以 root 运行，所以：只读取普通文件（不跟符号链接）、读取之后先复制到自己的临时目录再验证和使用（防止验证之后被换掉），
+# 并且绝不往 update/ 里写任何东西；状态写在 root 拥有的 update-status/ 里（业务进程只读）。
+UPDATE_DIR="$DATA_DIR/update"
+STATUS_DIR="$DATA_DIR/update-status"
+STATUS="$STATUS_DIR/status.json"
+INSTALLED="$STATE_DIR/$COMPONENT.installed"     # 两行：seq、digest
+mkdir -p "$STATE_DIR" "$STATUS_DIR"
+chmod 755 "$STATUS_DIR"
+WORK="$(mktemp -d)"
+trap 'rm -rf "$WORK"' EXIT
+OFFER_MANIFEST="$WORK/offer.manifest"
+OFFER_SIG="$WORK/offer.sig"
+
+# 把业务进程放的清单和签名复制到临时目录；不是普通文件（缺失、符号链接）就当作没有
+fetch_offer() {
+  rm -f "$OFFER_MANIFEST" "$OFFER_SIG"
+  for name in offer.manifest offer.sig; do
+    f="$UPDATE_DIR/$name"
+    if [ -f "$f" ] && [ ! -L "$f" ]; then head -c 8192 "$f" > "$WORK/$name"; fi
+  done
+}
+
+now() { date +%s; }
+
+# 状态文件：Agent / Probe 读它并随心跳报给面板。root 写，业务进程只读。
+write_status() { # state available_json error
+  tmp="$(mktemp "$STATUS_DIR/.status.XXXXXX")"
+  printf '{"state":"%s","current":"%s","available":%s,"error":"%s","at":%s}\n' \
+    "$1" "$(current_digest)" "${2:-null}" "$(printf '%s' "${3:-}" | tr -d '"\\\n' | cut -c1-200)" "$(now)" > "$tmp"
+  chmod 644 "$tmp"
+  mv -f "$tmp" "$STATUS"
+}
+
+current_digest() { [ -r "$INSTALLED" ] && sed -n 2p "$INSTALLED" || echo ""; }
+installed_seq() { [ -r "$INSTALLED" ] && sed -n 1p "$INSTALLED" || echo 0; }
+
+# 从扁平的清单里取字段（清单由 CI 生成，只有字符串和整数，没有嵌套）
+field() { sed -n 's/.*"'"$1"'":"\([^"]*\)".*/\1/p' "$OFFER_MANIFEST" | head -n 1; }
+num_field() { sed -n 's/.*"'"$1"'":\([0-9][0-9]*\).*/\1/p' "$OFFER_MANIFEST" | head -n 1; }
+
+# 验签 + 字段校验。成功时设置 M_DIGEST、M_TAG、M_VERSION、M_SEQ；失败返回非 0，原因在 ERR。
+verify_offer() {
+  ERR=""
+  [ -s "$OFFER_MANIFEST" ] && [ -s "$OFFER_SIG" ] || { ERR="no offer"; return 1; }
+  [ "$(wc -c < "$OFFER_MANIFEST")" -le 4096 ] || { ERR="manifest too large"; return 1; }
+  sigbin="$WORK/sig.bin"
+  base64 -d "$OFFER_SIG" > "$sigbin" 2>/dev/null || { ERR="bad signature encoding"; return 1; }
+  openssl dgst -sha256 -verify "$PUBKEY" -signature "$sigbin" "$OFFER_MANIFEST" >/dev/null 2>&1 || { ERR="signature check failed"; return 1; }
+  [ "$(field component)" = "$COMPONENT" ] || { ERR="manifest is for another component"; return 1; }
+  [ "$(field image)" = "$IMAGE_REPO" ] || { ERR="manifest names another repository"; return 1; }
+  M_DIGEST="$(field digest)"
+  case "$M_DIGEST" in sha256:*) ;; *) ERR="bad digest"; return 1 ;; esac
+  [ "${#M_DIGEST}" -eq 71 ] && [ -z "$(printf '%s' "${M_DIGEST#sha256:}" | tr -d '0-9a-f')" ] || { ERR="bad digest"; return 1; }
+  M_TAG="$(field tag)"; M_VERSION="$(field version)"; M_SEQ="$(num_field seq)"
+  [ -n "$M_SEQ" ] || { ERR="no seq"; return 1; }
+  [ "$M_SEQ" -gt "$(installed_seq)" ] || { ERR="stale manifest (seq $M_SEQ <= $(installed_seq))"; return 1; }
+}
+
+available_json() { printf '{"version":"%s","tag":"%s","digest":"%s","seq":%s}' "$(printf '%s' "$M_VERSION" | tr -d '"\\')" "$(printf '%s' "$M_TAG" | tr -d '"\\')" "$M_DIGEST" "$M_SEQ"; }
+
+do_check() {
+  fetch_offer
+  if ! verify_offer; then
+    # 没有新清单，或者清单已经安装过：不算错误，只是没有更新
+    case "$ERR" in
+      "no offer"|"stale manifest"*) write_status up_to_date null "" ;;
+      *) write_status invalid null "$ERR"; echo "offer rejected: $ERR" >&2 ;;
+    esac
+    return 0
+  fi
+  if [ "$M_DIGEST" = "$(current_digest)" ]; then
+    write_status up_to_date null ""
+    return 0
+  fi
+  write_status available "$(available_json)" ""
+  echo "update available: $M_TAG ($M_DIGEST)"
+  if [ "$POLICY" = auto ]; then do_apply; fi
+  return 0
+}
+
+do_apply() {
+  rm -f "$UPDATE_DIR/apply.request"
+  fetch_offer
+  verify_offer || { write_status invalid null "$ERR"; echo "refusing to apply: $ERR" >&2; return 1; }
+  avail="$(available_json)"
+  write_status applying "$avail" ""
+  ref="$IMAGE_REPO@$M_DIGEST"
+  if [ -n "${AUTHFILE:-}" ]; then export REGISTRY_AUTH_FILE="$AUTHFILE"; fi
+  if ! podman pull --quiet "$ref" >/dev/null 2>&1; then
+    write_status failed "$avail" "pull failed"; echo "pull failed: $ref" >&2; return 1
+  fi
+  prev="$(cat "$ENV_FILE" 2>/dev/null || true)"
+  printf 'IMAGE=%s\n' "$ref" > "$ENV_FILE.new" && mv -f "$ENV_FILE.new" "$ENV_FILE"
+  systemctl restart "$UNIT" || true
+  # 健康确认：服务在跑，并且 20 秒内没有再被重启（崩溃循环算失败）
+  sleep 5
+  before="$(systemctl show -p NRestarts --value "$UNIT" 2>/dev/null || echo 0)"
+  sleep 15
+  after="$(systemctl show -p NRestarts --value "$UNIT" 2>/dev/null || echo 0)"
+  if systemctl is-active --quiet "$UNIT" && [ "$before" = "$after" ]; then
+    printf '%s\n%s\n' "$M_SEQ" "$M_DIGEST" > "$INSTALLED"
+    write_status up_to_date null ""
+    echo "updated to $M_TAG"
+    return 0
+  fi
+  echo "new version did not become healthy, rolling back" >&2
+  if [ -n "$prev" ]; then printf '%s\n' "$prev" > "$ENV_FILE"; fi
+  systemctl restart "$UNIT" || true
+  write_status rolled_back "$avail" "new version did not become healthy"
+  return 1
+}
+
+case "$CMD" in
+  check) do_check ;;
+  apply) do_apply ;;
+esac

packaging/update/release-key.pub.pem

@@ -0,0 +1,4 @@
+-----BEGIN PUBLIC KEY-----
+MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEfw7EkNcl0FZqOETK+Vt55RMZ9K0q
+YOrtO3Vso/QNdSMmepQlx1Q3v+KkN7ro3AY3I6DT2Q2txJu5pS7qzutSQA==
+-----END PUBLIC KEY-----