發現問題：
啟動 node 項目ReactNative時候出現報錯Error: ENOSPC: no space left on device, watch
[root@iz2zeihk6kfcls5kwmqzj1z JFReactNativeProject]# npm start
> wk_rn@0.0.1 start /app/jenkins_workspace/workspace/JFReactNativeProject
> react-native start
┌──────────────────────────────────────────────────────────────────────────────┐
│ │
│ Running Metro Bundler on port 8081. │
│ │
│ Keep Metro running while developing on any JS projects. Feel free to │
│ close this tab and run your own Metro instance if you prefer. │
│ │
│ https://github.com/facebook/react-native │
│ │
└──────────────────────────────────────────────────────────────────────────────┘
Looking for JS files in
/app/jenkins_workspace/workspace/JFReactNativeProject
Loading dependency graph...fs.js:1413
throw error;
^
Error: ENOSPC: no space left on device, watch '/app/jenkins_workspace/workspace/JFReactNativeProject/node_modules/.staging/react-native-ddd311e5/ReactAndroid/src/androidTest/java/com/facebook/react/testing/idledetection'
at FSWatcher.start (fs.js:1407:26)
at Object.fs.watch (fs.js:1444:11)
at NodeWatcher.watchdir (/app/jenkins_workspace/workspace/JFReactNativeProject/node_modules/_sane@4.1.0@sane/src/node_watcher.js:159:22)
at Walker.<anonymous> (/app/jenkins_workspace/workspace/JFReactNativeProject/node_modules/_sane@4.1.0@sane/src/common.js:109:31)
at Walker.emit (events.js:182:13)
at /app/jenkins_workspace/workspace/JFReactNativeProject/node_modules/_walker@1.0.7@walker/lib/walker.js:69:16
at go$readdir$cb (/app/jenkins_workspace/workspace/JFReactNativeProject/node_modules/_graceful-fs@4.2.2@graceful-fs/graceful-fs.js:187:14)
at FSReqWrap.oncomplete (fs.js:169:20)
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! wk_rn@0.0.1 start: `react-native start`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the wk_rn@0.0.1 start script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
npm ERR! A complete log of this run can be found in:
npm ERR! /root/.npm/_logs/2019-09-25T06_57_58_754Z-debug.log
解決辦法：
ENOSPC的含義是 Error No more hard-disk space available（沒有更多的磁盤空間可以使用）
首先使用df -hT發現磁盤空間還有很多
然后從報錯日志中發現FSWatcher和Object.fs.watch字段，然后查看系統允許用戶監聽文件數相關內容
#表示同一用戶同時可以添加的watch數目（watch一般是針對目錄，決定了同時同一用戶可以監控的目錄數量）
[root@iz2zeihk6kfcls5kwmqzj1z JFReactNativeProject]# cat /proc/sys/fs/inotify/max_user_watches
8192
[root@iz2zeihk6kfcls5kwmqzj1z JFReactNativeProject]# echo 100000 > /proc/sys/fs/inotify/max_user_watches
[root@iz2zeihk6kfcls5kwmqzj1z JFReactNativeProject]# cat /proc/sys/fs/inotify/max_user_watches
100000
永久生效方法如下：（建議采用此方法）
vim /etc/sysctl.conf
fs.inotify.max_user_watches = 100000（后面值根據實際情況可自行調整）
添加並運行/sbin/sysctl -p即可
啟動驗證：
再次啟動，正常
[root@iz2zeihk6kfcls5kwmqzj1z JFReactNativeProject]# npm start
> wk_rn@0.0.1 start /app/jenkins_workspace/workspace/JFReactNativeProject
> react-native start
┌──────────────────────────────────────────────────────────────────────────────┐
│ │
│ Running Metro Bundler on port 8081. │
│ │
│ Keep Metro running while developing on any JS projects. Feel free to │
│ close this tab and run your own Metro instance if you prefer. │
│ │
│ https://github.com/facebook/react-native │
│ │
└──────────────────────────────────────────────────────────────────────────────┘
Looking for JS files in
/app/jenkins_workspace/workspace/JFReactNativeProject
Loading dependency graph, done.
知識點：
inotify 的默認內核參數
/proc/sys/fs/inotify/max_queued_events默認值:16384該文件中的值為調用inotify_init時分配給inotify instance中可排隊的event的數目的最大值，超出這個值得事件被丟棄，但會觸發IN_Q_OVERFLOW事件/proc/sys/fs/inotify/max_user_instances默認值:128指定了每一個real user ID可創建的inotify instatnces的數量上限/proc/sys/fs/inotify/max_user_watches默認值:8192指定了每個inotify instance相關聯的watches的上限
注意: max_queued_events 是 Inotify 管理的隊列的最大長度，文件系統變化越頻繁，這個值就應該越大
如果你在日志中看到Event Queue Overflow，說明 max_queued_events 太小需要調整參數后再次使用.