服务器上启动mongodb的错误是什么意思

Question

2017-05-02T16:16:31.190+0800 I CONTROL  [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'.
2017-05-02T16:16:31.190+0800 I CONTROL  [initandlisten] **        We suggest setting it to 'never'
2017-05-02T16:16:31.190+0800 I CONTROL  [initandlisten]
2017-05-02T16:16:31.190+0800 I CONTROL  [initandlisten] ** WARNING: soft rlimits too low. rlimits set to 3901 processes, 1000000 files. Number of processes should be at least 500000 : 0.5 times number of files.
2017-05-02T16:16:31.190+0800 I CONTROL  [initandlisten]
2017-05-02T16:16:31.265+0800 I FTDC     [initandlisten] Initializing full-time diagnostic data capture with directory '/var/mongodb/data/diagnostic.data'
2017-05-02T16:16:31.279+0800 I NETWORK  [HostnameCanonicalizationWorker] Starting hostname canonicalization worker
2017-05-02T16:16:31.282+0800 I NETWORK  [initandlisten] waiting for connections on port 27017
2017-05-02T17:13:19.617+0800 I NETWORK  [initandlisten] connection accepted from 127.0.0.1:52260 #1 (1 connection now open)
2017-05-02T17:13:48.843+0800 I NETWORK  [conn1] end connection 127.0.0.1:52260 (0 connections now open)
2017-05-02T17:26:19.310+0800 I CONTROL  [signalProcessingThread] got signal 15 (Terminated), will terminate after current cmd ends
2017-05-02T17:26:19.310+0800 I FTDC     [signalProcessingThread] Shutting down full-time diagnostic data capture
2017-05-02T17:26:19.312+0800 I CONTROL  [signalProcessingThread] now exiting
2017-05-02T17:26:19.312+0800 I NETWORK  [signalProcessingThread] shutdown: going to close listening sockets...
2017-05-02T17:26:19.312+0800 I NETWORK  [signalProcessingThread] closing listening socket: 6
2017-05-02T17:26:19.312+0800 I NETWORK  [signalProcessingThread] closing listening socket: 7
2017-05-02T17:26:19.312+0800 I NETWORK  [signalProcessingThread] removing socket file: /tmp/mongodb-27017.sock
2017-05-02T17:26:19.313+0800 I NETWORK  [signalProcessingThread] shutdown: going to flush diaglog...
2017-05-02T17:26:19.313+0800 I NETWORK  [signalProcessingThread] shutdown: going to close sockets...
2017-05-02T17:26:19.313+0800 I STORAGE  [signalProcessingThread] WiredTigerKVEngine shutting down
2017-05-02T17:26:19.547+0800 I STORAGE  [signalProcessingThread] shutdown: removing fs lock...
2017-05-02T17:26:19.547+0800 I CONTROL  [signalProcessingThread] dbexit:  rc: 0

Answer 1

这里列出的只是WARNING，并不会造成服务器退出。如果这这两个WARNING感兴趣，可查看文档:
Disable Transparent Huge Pages (THP)
UNIX ulimit Settings
服务器退出的原因是：

2017-05-02T17:26:19.310+0800 I CONTROL [signalProcessingThread] got signal 15 (Terminated), will terminate after current cmd ends

实际上这是一个正常结束，可能是kill或其他类似的命令结束了mongod。

Answer 2

有警告啊： soft rlimits too low

Answer 3

https://serverfault.com/quest...
这里有提到在 systemctl service 下需要 fork=false：
processManagement:
fork: false