无法在CentOS 7上启动MongoDB 3.2.1

Question

我按照本文档在CentOS 7上安装了MongoDB 3.2.1。安装完成后，我将var/lib/mongo和var/log/mongodb/mongod.log的所有者和组更改为root:root。

当我用service mongod start启动mongodb时，它只显示

Starting mongod (via systemctl):  Job for mongod.service failed. See 'systemctl status mongod.service' and 'journalctl -xn' for details.[FAILED]

我已经运行了这两个命令来显示详细信息。

systemctl status mongod.service展示

mongod.service - SYSV: Mongo is a scalable, document-oriented database.
   Loaded: loaded (/etc/rc.d/init.d/mongod)
   Active: failed (Result: exit-code) since Wen 2016-01-27 18:32:46 CST; 14s ago
  Process: 24913 ExecStart=/etc/rc.d/init.d/mongod start (code=exited, status=1/FAILURE)
 Main PID: 23711 (code=exited, status=0/SUCCESS)

1月 27 18:32:45 server1 systemd[1]: Starting SYSV: Mongo is a scalable, document-oriented database....
1月 27 18:32:45 server1 runuser[24920]: pam_unix(runuser:session): session opened for user mongod by (uid=0)
1月 27 18:32:46 server1 mongod[24913]: Starting mongod: [FAILED]
1月 27 18:32:46 server1 systemd[1]: mongod.service: control process exited, code=exited status=1
1月 27 18:32:46 server1 systemd[1]: Failed to start SYSV: Mongo is a scalable, document-oriented database..
1月 27 18:32:46 server1 systemd[1]: Unit mongod.service entered failed state.

journalctl -xn展示

-- Logs begin at 日 2016-01-24 16:33:05 CST, end at Wen 2016-01-27 18:32:46 CST. --
1月 27 18:32:15 server1 sshd[24879]: pam_succeed_if(sshd:auth): requirement "uid >= 1000" not met by user "root"
1月 27 18:32:17 server1 sshd[24879]: Failed password for root from 182.100.67.59 port 10013 ssh2
1月 27 18:32:45 server1 sudo[24896]: root : TTY=pts/0 ; PWD=/var/log/mongodb ; USER=root ; COMMAND=/sbin/service mongod start
1月 27 18:32:45 server1 systemd[1]: Starting SYSV: Mongo is a scalable, document-oriented database....
-- Subject: Unit mongod.service has begun with start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit mongod.service has begun starting up.
1月 27 18:32:45 server1 runuser[24920]: pam_unix(runuser:session): session opened for user mongod by (uid=0)
1月 27 18:32:46 server1 runuser[24920]: pam_unix(runuser:session): session closed for user mongod
1月 27 18:32:46 server1 mongod[24913]: Starting mongod: [FAILED]
1月 27 18:32:46 server1 systemd[1]: mongod.service: control process exited, code=exited status=1
1月 27 18:32:46 server1 systemd[1]: Failed to start SYSV: Mongo is a scalable, document-oriented database..
-- Subject: Unit mongod.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit mongod.service has failed.
-- 
-- The result is failed.
1月 27 18:32:46 server1 systemd[1]: Unit mongod.service entered failed state.

我使用ssh密钥访问服务器，没有密码。

Answer 1

是否有理由将所有权更改为root？

/var/lib/mongo和/var/log/mongodb都应该是mongodb用户可写的。

默认情况下为mongodb:mongodb。查看哪个用户在/etc/init.d/mongodb中运行mongodb服务。如果它类似于DAEMONUSER=${DAEMONUSER:-mongodb}，则将您的目录切换回此用户。

Answer 2

在CentOS 7中默认启用的selinux权限可能会导致非常类似的问题。可以通过禁用selinux或使用以下命令将正确的上下文添加到mongo数据库路径来修复此问题：

chcon -R -t mongod_var_lib_t /var/lib/mongod

Answer 3

我尝试了人们提到的所有东西，但都没有成功，所以我结束了为它构建一个简单的单元服务文件，因为在我的例子中，问题看起来与初始化脚本(https://jira.mongodb.org/plugins/servlet/mobile#issue/SERVER-18439/comment/915785)有关。

我在这里创建了服务文件：

/etc/systmd/system/mongodb.service

以此为内容：

[Unit]
Description=MongoDB Database Service
Wants=network.target
After=network.target
[Service]
Type=forking
PIDFile=/var/run/mongodb/mongod.pid
ExecStart=/usr/bin/mongod --config /etc/mongod.conf
ExecReload=/bin/kill -HUP $MAINPID
Restart=always
User=mongod
Group=mongod
StandardOutput=syslog
StandardError=syslog
[Install]
WantedBy=multi-user.target

在那之后，我所要做的就是这样开始：

$ sudo systemctl start mongodb

我希望这对任何人都有帮助。