啟動(dòng)不了西饵，分別報(bào)錯(cuò)如下：
ERROR: child process failed, exited with error number 1
ERROR: child process failed, exited with error number 51
1绩郎，第一次嘗試啟動(dòng)mongod刹泄，報(bào)錯(cuò)，取消執(zhí)行窃植，
ai-learning-mongo-1-[root@ai-learning-mongo-1 mongodb]# su - mongo
Last login: Tue Jan? 7 16:40:11 CST 2020 on pts/1
[mongo@ai-learning-mongo-1 ~]$ /app/mongodb/bin/mongod --config /app/mongodb/mongod.conf &
[1] 16477
[mongo@ai-learning-mongo-1 ~]$ about to fork child process, waiting until server is ready for connections.
forked process: 16479
ERROR: child process failed, exited with error number 1
To see additional information in this output, start without the "--fork" option.
^C
[1]+? Exit 1? ? ? ? ? ? ? ? ? /app/mongodb/bin/mongod --config /app/mongodb/mongod.conf
2，檢查目錄荐糜，發(fā)現(xiàn)配置文件權(quán)限不對(duì)巷怜，修改目錄權(quán)限
[mongo@ai-learning-mongo-1 ~]$ cd /app/mongodb/
[mongo@ai-learning-mongo-1 mongodb]$ ll
total 12
drwxr-xr-x 2 mongo mongo? 248 Feb 26? 2019 bin
drwxr-xr-x 8 mongo mongo? 295 Jan? 7 16:39 db
-r-------- 1 mongo mongo 1024 Feb 26? 2019 keyfile
drwxr-xr-x 2 mongo mongo? 24 Jan? 7 15:46 logs
-rw-r--r-- 1 root? root? 785 Feb 26? 2019 mongod.conf
-rw-r--r-- 1 mongo mongo? ? 6 Jan? 7 16:39 mongod.pid
[mongo@ai-learning-mongo-1 mongodb]$ chown -R? mongo:mongo mongod.conf
chown: changing ownership of ‘mongod.conf’: Operation not permitted
[mongo@ai-learning-mongo-1 mongodb]$ exit
logout
3葛超，修改配置文件權(quán)限
ai-learning-mongo-1-[root@ai-learning-mongo-1 ~]# chown -R mongo:mongo /app/mongodb/mongod.conf
4，嘗試重新啟動(dòng)延塑，還是報(bào)一樣的錯(cuò)绣张，排查可能目錄屬主還有可能是其他用戶，繼續(xù)往下級(jí)目錄查看关带，發(fā)現(xiàn)bin目錄下還是沒有改掉權(quán)限
[2020/1/7 16:47:59] [mongo@ai-learning-mongo-1 mongodb]$ cd bin/
[2020/1/7 16:48:00] [mongo@ai-learning-mongo-1 bin]$ ll
[2020/1/7 16:48:00] total 285444
[2020/1/7 16:48:00] -rwxr-xr-x 1 root root 10546472 Nov 14? 2018 bsondump
[2020/1/7 16:48:00] -rwxr-xr-x 1 root root? ? 7770 Nov 14? 2018 install_compass
[2020/1/7 16:48:00] -rwxr-xr-x 1 root root 33750624 Nov 14? 2018 mongo
[2020/1/7 16:48:00] -rwxr-xr-x 1 root root 59532264 Nov 14? 2018 mongod
[2020/1/7 16:48:00] -rwxr-xr-x 1 root root 12848240 Nov 14? 2018 mongodump
[2020/1/7 16:48:00] -rwxr-xr-x 1 root root 10884072 Nov 14? 2018 mongoexport
[2020/1/7 16:48:00] -rwxr-xr-x 1 root root 10767240 Nov 14? 2018 mongofiles
[2020/1/7 16:48:00] -rwxr-xr-x 1 root root 11024432 Nov 14? 2018 mongoimport
[2020/1/7 16:48:00] -rwxr-xr-x 1 root root 59036976 Nov 14? 2018 mongoperf
[2020/1/7 16:48:00] -rwxr-xr-x 1 root root 13955512 Nov 14? 2018 mongoreplay
[2020/1/7 16:48:00] -rwxr-xr-x 1 root root 13941224 Nov 14? 2018 mongorestore
[2020/1/7 16:48:00] -rwxr-xr-x 1 root root 34171112 Nov 14? 2018 mongos
[2020/1/7 16:48:00] -rwxr-xr-x 1 root root 11080688 Nov 14? 2018 mongostat
[2020/1/7 16:48:00] -rwxr-xr-x 1 root root 10721912 Nov 14? 2018 mongotop
[2020/1/7 16:48:34] [mongo@ai-learning-mongo-1 bin]$ exit
[2020/1/7 16:48:34] logout
5侥涵，修改整個(gè)目錄結(jié)構(gòu)的權(quán)限
[2020/1/7 16:49:07] ai-learning-mongo-1-[root@ai-learning-mongo-1 mongodb]# chown -R mongo:mongo /app/mongodb/
6，嘗試啟動(dòng)宋雏，報(bào)error number 51
[2020/1/7 17:09:53] [mongo@ai-learning-mongo-1 db]$ /app/mongodb/bin/mongod --config /app/mongodb/mongod.conf &
[2020/1/7 17:09:53] [1] 18399
[2020/1/7 17:09:53] [mongo@ai-learning-mongo-1 db]$ about to fork child process, waiting until server is ready for connections.
[2020/1/7 17:09:53] forked process: 18401
[2020/1/7 17:09:56] ERROR: child process failed, exited with error number 51
[2020/1/7 17:09:56] To see additional information in this output, start without the "--fork" option.
[2020/1/7 17:10:41] ^C
[2020/1/7 17:10:41] [1]+? Exit 51? ? ? ? ? ? ? ? /app/mongodb/bin/mongod --config /app/mongodb/mongod.conf
7独令，啟動(dòng)不了mongodb,查看日志 less /app/mongodb/logs/mongod.log
8，根據(jù)報(bào)錯(cuò)好芭，open： too many open files ,認(rèn)為應(yīng)該是open files 數(shù)量不夠燃箭，查閱資料修改
https://blog.csdn.net/qq_26614295/article/details/81502338
根據(jù)以上文章修改ulimit -HSn 102400 參數(shù)，并且刪除lock文件舍败，清空log/目錄下日志招狸，
[2020/1/7 17:25:25] [mongo@ai-learning-mongo-1 db]$ rm -f mongod.lock
[2020/1/7 17:25:29] [mongo@ai-learning-mongo-1 mongodb]$ cd logs
[2020/1/7 17:25:30] [mongo@ai-learning-mongo-1 logs]$ ll
[2020/1/7 17:25:30] total 24
[2020/1/7 17:25:30] -rw-rw-r-- 1 mongo mongo 21997 Jan? 7 17:09 mongod.log
[2020/1/7 17:25:55] [mongo@ai-learning-mongo-1 logs]$ mv mongod.log /tmp/mongod.log.25
9，重啟啟動(dòng)邻薯，成功啟動(dòng)mongod?
[2020/1/7 17:26:09] [mongo@ai-learning-mongo-1 logs]$ /app/mongodb/bin/mongod --config /app/mongodb/mongod.conf &
[2020/1/7 17:26:09] [1] 19549
[2020/1/7 17:26:09] [mongo@ai-learning-mongo-1 logs]$ about to fork child process, waiting until server is ready for connections.
[2020/1/7 17:26:09] forked process: 19552
[2020/1/7 17:26:21] child process started successfully, parent exiting
[2020/1/7 17:26:29]
[2020/1/7 17:26:29] [1]+? Done? ? ? ? ? ? ? ? ? ? /app/mongodb/bin/mongod --config /app/mongodb/mongod.conf
[2020/1/7 17:26:35] [mongo@ai-learning-mongo-1 logs]$ ps -ef | grep mongod
[2020/1/7 17:26:35] appuser? 13359? 9538? 0 16:01 pts/0? ? 00:00:00 vi mongod.conf
[2020/1/7 17:26:35] mongo? ? 19552? ? 1 50 17:26 ?? ? ? ? 00:00:13 /app/mongodb/bin/mongod --config /app/mongodb/mongod.conf
[2020/1/7 17:26:35] mongo? ? 19679 19442? 0 17:26 pts/1? ? 00:00:00 grep --color=auto mongod
10裙戏，另外一臺(tái)服務(wù)器修改以上參數(shù)，并且修改目錄權(quán)限厕诡，重啟發(fā)現(xiàn)報(bào)錯(cuò)error number 1
11累榜，查看mongod.log ，嘗試提高--maxConnes,啟動(dòng)失敗灵嫌，報(bào)錯(cuò)error number 1
[mongo@ai-learning-mongo-2 logs]$ /app/mongodb/bin/mongod --config /app/mongodb/mongod.conf --maxConns=2000 &?
12壹罚，根據(jù)日志鐘第二行，permissions on /app/mongodb/keyfile are too open ,懷疑/app/mongodb/keyfile文件權(quán)限給多了寿羞，查看權(quán)限猖凛，果然給多了，收回權(quán)限改為400绪穆，
[mongo@ai-learning-mongo-2 logs]$ ll /app/mongodb/keyfile
[2020/1/7 17:39:47] -rwxrwxrwx 1 mongo mongo 1024 Feb 26? 2019 /app/mongodb/keyfile
[2020/1/7 17:40:12] [mongo@ai-learning-mongo-2 logs]$ exit
[2020/1/7 17:40:12] logout
[2020/1/7 17:40:23] ai-learning-mongo-2-[root@ai-learning-mongo-2 mongodb]# chmod 400 /app/mongodb/keyfile?
13辨泳，再次嘗試啟動(dòng)，此次啟動(dòng)成功
[2020/1/7 17:41:14] ai-learning-mongo-2-[root@ai-learning-mongo-2 mongodb]# su - mongo
[2020/1/7 17:41:15] Last login: Tue Jan? 7 17:33:56 CST 2020 on pts/2
[2020/1/7 17:41:27] [mongo@ai-learning-mongo-2 ~]$? /app/mongodb/bin/mongod --config /app/mongodb/mongod.conf &
[2020/1/7 17:41:27] [1] 21252
[2020/1/7 17:41:27] [mongo@ai-learning-mongo-2 ~]$ about to fork child process, waiting until server is ready for connections.
[2020/1/7 17:41:27] forked process: 21254
[2020/1/7 17:41:34] child process started successfully, parent exiting
[2020/1/7 17:42:01]
[2020/1/7 17:42:01] [1]+? Done? ? ? ? ? ? ? ? ? ? /app/mongodb/bin/mongod --config /app/mongodb/mongod.conf
[2020/1/7 17:42:01] [mongo@ai-learning-mongo-2 ~]$
[2020/1/7 17:42:07] [mongo@ai-learning-mongo-2 ~]$ ps -ef | grep mongo
[2020/1/7 17:42:07] root? ? 21222 20426? 0 17:41 pts/2? ? 00:00:00 su - mongo
[2020/1/7 17:42:07] mongo? ? 21223 21222? 0 17:41 pts/2? ? 00:00:00 -bash
[2020/1/7 17:42:07] mongo? ? 21254? ? 1 17 17:41 ?? ? ? ? 00:00:06 /app/mongodb/bin/mongod --config /app/mongodb/mongod.conf
[2020/1/7 17:42:07] mongo? ? 21389 21223? 0 17:42 pts/2? ? 00:00:00 ps -ef
[2020/1/7 17:42:07] mongo? ? 21390 21223? 0 17:42 pts/2? ? 00:00:00 grep --color=auto mongo
