MongoDBに接続できなかった

動作環境

Linux conoharch 4.0.4-2-ARCH
MongoDB shell version: 3.0.6

エラー

[root@conoharch ~]#mongo

MongoDB shell version: 3.0.6
connecting to: test
2015-09-21T10:16:20.453+0900 W NETWORK  Failed to connect to 127.0.0.1:27017, reason: errno:111 Connection refused
2015-09-21T10:16:20.454+0900 E QUERY    Error: couldn't connect to server 127.0.0.1:27017 (127.0.0.1), connection attempt failed
    at connect (src/mongo/shell/mongo.js:179:14)
    at (connect):1:6 at src/mongo/shell/mongo.js:179
exception: connect failed

ログを見よう

[root@conoharch ~]#tail -n 20 /var/log/mongodb/mongod.log

2015-09-21T10:16:03.798+0900 E NETWORK  [initandlisten] Failed to unlink socket file /tmp/mongodb-27017.sock errno:1 Operation not permitted
2015-09-21T10:16:03.799+0900 I -        [initandlisten] Fatal Assertion 28578
2015-09-21T10:16:03.799+0900 I -        [initandlisten]

***aborting after fassert() failure

解決

↑のログを読むと/tmp/mongodb-27017.sockが悪さしてるらしいのでとりあえず消す

[root@conoharch ~]#rm /tmp/mongodb-27017.sock

確認

[root@conoharch ~]#systemctl restart mongodb
[root@conoharch ~]# mongo
MongoDB shell version: 3.0.6
connecting to: test
Welcome to the MongoDB shell.
For interactive help, type "help".
For more comprehensive documentation, see
        http://docs.mongodb.org/
Questions? Try the support group
        http://groups.google.com/group/mongodb-user
Server has startup warnings:
2015-09-21T10:19:47.967+0900 I CONTROL  [initandlisten]
2015-09-21T10:19:47.967+0900 I CONTROL  [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/enabled is 'always'.
2015-09-21T10:19:47.967+0900 I CONTROL  [initandlisten] **        We suggest setting it to 'never'
2015-09-21T10:19:47.967+0900 I CONTROL  [initandlisten]
2015-09-21T10:19:47.967+0900 I CONTROL  [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'.
2015-09-21T10:19:47.967+0900 I CONTROL  [initandlisten] **        We suggest setting it to 'never'
2015-09-21T10:19:47.967+0900 I CONTROL  [initandlisten]
> ^C
bye

みたいな感じで「test」とかいうデータベースに接続されれば成功。