diff --git a/packages/hydrooj/src/entry/worker.ts b/packages/hydrooj/src/entry/worker.ts
index 4a57ed837..735219f17 100644
--- a/packages/hydrooj/src/entry/worker.ts
+++ b/packages/hydrooj/src/entry/worker.ts
@@ -44,7 +44,7 @@ export async function apply(ctx: Context) {
     await ctx.root.start();
     require('../lib/index');
     await lib(pending, fail, ctx);
-    require('../service/monitor');
+    ctx.plugin(require('../service/monitor'));
     await service(pending, fail, ctx);
     await builtinModel(ctx);
     await model(pending, fail, ctx);
diff --git a/packages/hydrooj/src/interface.ts b/packages/hydrooj/src/interface.ts
index 7a972e02d..f81f08872 100644
--- a/packages/hydrooj/src/interface.ts
+++ b/packages/hydrooj/src/interface.ts
@@ -649,7 +649,6 @@ export interface HydroService {
     /** @deprecated */
     bus: Context,
     db: typeof import('./service/db').default,
-    monitor: typeof import('./service/monitor'),
     server: typeof import('./service/server'),
     storage: typeof import('./service/storage').default,
 }
diff --git a/packages/hydrooj/src/service/monitor.ts b/packages/hydrooj/src/service/monitor.ts
index f2bee6dd8..328f6cff9 100644
--- a/packages/hydrooj/src/service/monitor.ts
+++ b/packages/hydrooj/src/service/monitor.ts
@@ -2,6 +2,7 @@ import { dump } from 'js-yaml';
 import superagent from 'superagent';
 import type { StatusUpdate } from '@hydrooj/utils/lib/sysinfo';
 import * as sysinfo from '@hydrooj/utils/lib/sysinfo';
+import { Context } from '../context';
 import { Logger } from '../logger';
 import * as bus from './bus';
 import db from './db';
@@ -90,8 +91,9 @@ export async function updateJudge(args) {
     );
 }
 
-if (process.env.NODE_APP_INSTANCE === '0') {
-    bus.on('ready', async () => {
+export function apply(ctx: Context) {
+    if (process.env.NODE_APP_INSTANCE !== '0') return;
+    ctx.on('app/started', async () => {
         sysinfo.get().then((info) => {
             coll.updateOne(
                 { mid: info.mid, type: 'server' },
@@ -103,5 +105,3 @@ if (process.env.NODE_APP_INSTANCE === '0') {
         });
     });
 }
-
-global.Hydro.service.monitor = { feedback, update, updateJudge };