[Linux] MongoDB Replica Set with Auth & KeyFile @ Ubuntu 12.04

建 cluster 不見得需要帳號管控，因為多數處在保護的網路環境，而 MongoDB 預設沒有帳密管控且帳密管控做的很簡單，分成 read-only 跟 read-write 模式。而使用認證的主因是為了遠端關掉機器，沒有認證機制的服務僅能透過 localhost 關掉服務，有一派說是透過 service mongodb stop 指令，又有一派說直接 kill process 即可，但有文章說如此容易造成問題？還是要用正式的關機流程比較妥( mongo> db.shutdownServer() )。

參考文件：

• http://docs.mongodb.org/manual/tutorial/manage-mongodb-processes/
• http://docs.mongodb.org/manual/administration/replica-sets/
• http://cookbook.mongodb.org/operations/convert-replica-set-to-replicated-shard-cluster/

架設 Replica Set 的流程：

1. 啟動多台 mongod --replSet set_name
2. 挑選一台 mongod 登入
3. 使用 rs.init() 初始化後，再用 rs.add() 加入其他 mongod 或是使用 db.runCommand({'replSetInitiate':{'members':[]}}) 一次新增

架設需要認證的 Replica Set 的流程：

1. 用 default 模式啟動一台 mongod
2. 建立帳號
3. 建立 keyFile (檔案內容隨意，但需要多過6個字元)
4. 關掉後以 --replSet set_name 與 --keyFile key_file_path 模式啟動多支 mongod
5. 登入一台 mongod 以及完成帳號認證
6. 使用 rs.init() 初始化後，再用 rs.add() 加入其他 mongod 或是使用 db.runCommand({'replSetInitiate':{'members':[]}}) 一次新增

上述兩者流程的差別在於後者要先建帳號後，再用 --replSet 跟 --keyFile 模式啟動。而後，為了測試就寫了隻 script 筆記一下:

未使用認證模式：

$ python replset_init.py --reset

Init DB(0), Port: 30000, Path: /home/id/data/mongodb-study/cluster/db/db-0
 $ mongod --dbpath /home/id/data/mongodb-study/cluster/db/db-0 --port 30000 --oplogSize 700 --logpath /home/id/data/mongodb-study/cluster/log/db-0.log --rest --replSet firstset

Init DB(1), Port: 30001, Path: /home/id/data/mongodb-study/cluster/db/db-1
 $ mongod --dbpath /home/id/data/mongodb-study/cluster/db/db-1 --port 30001 --oplogSize 700 --logpath /home/id/data/mongodb-study/cluster/log/db-1.log --rest --replSet firstset

Init DB(2), Port: 30002, Path: /home/id/data/mongodb-study/cluster/db/db-2
 $ mongod --dbpath /home/id/data/mongodb-study/cluster/db/db-2 --port 30002 --oplogSize 700 --logpath /home/id/data/mongodb-study/cluster/log/db-2.log --rest --replSet firstset

nohup: ignoring input and appending output to `nohup.out'
nohup: ignoring input and appending output to `nohup.out'
nohup: ignoring input and appending output to `nohup.out'

Waiting...
        localhost:30000: .....OK
        localhost:30001: OK
        localhost:30002: OK

Connect to localhost:30000

Initialize the First Replica Set:

$ monogo localhost:30000/admin
mongo> db.runCommand( {'replSetInitiate': {'_id': 'firstset', 'members': [{'host': 'localhost:30000', '_id': 1}, {'host': 'localhost:30001', '_id': 2}, {'host': 'localhost:30002', '_id': 3}]}} )

Result:
{u'info': u'Config now saved locally.  Should come online in about a minute.', u'ok': 1.0}

All is done.

server info:
 $ mongo localhost:30000/admin --eval 'printjson(rs.status())'

shutdown servers:
 $ mongo localhost:30000/admin --eval 'db.shutdownServer()'
 $ mongo localhost:30001/admin --eval 'db.shutdownServer()'
 $ mongo localhost:30002/admin --eval 'db.shutdownServer()'

使用認證模式：

$ python replset_init.py --reset --auth-key-file keyfile --auth-user account --auth-pass password

Init DB(0), Port: 30000, Path: /home/id/data/mongodb-study/cluster/db/db-0
 $ mongod --dbpath /home/id/data/mongodb-study/cluster/db/db-0 --port 30000 --oplogSize 700 --logpath /home/id/data/mongodb-study/cluster/log/db-0.log --rest
nohup: ignoring input and appending output to `nohup.out'

Waiting...
        localhost:30000: ..OK

Connect to localhost:30000

Initialize the First Replica Set:

$ monogo localhost:30000/admin
mongo> db.addUser( {user: "account", pwd:"password", roles:["userAdminAnyDatabase"] })

Add account done.

Restart the mongod:

Init DB(0), Port: 30000, Path: /home/id/data/mongodb-study/cluster/db/db-0
 $ mongod --dbpath /home/id/data/mongodb-study/cluster/db/db-0 --port 30000 --oplogSize 700 --logpath /home/id/data/mongodb-study/cluster/log/db-0.log --rest --replSet firstset --keyFile keyfile

Init DB(1), Port: 30001, Path: /home/id/data/mongodb-study/cluster/db/db-1
 $ mongod --dbpath /home/id/data/mongodb-study/cluster/db/db-1 --port 30001 --oplogSize 700 --logpath /home/id/data/mongodb-
study/cluster/log/db-1.log --rest --replSet firstset --keyFile keyfile

nohup: ignoring input and appending output to `nohup.out'
Init DB(2), Port: 30002, Path: /home/id/data/mongodb-study/cluster/db/db-2
 $ mongod --dbpath /home/id/data/mongodb-study/cluster/db/db-2 --port 30002 --oplogSize 700 --logpath /home/id/data/mongodb-
study/cluster/log/db-2.log --rest --replSet firstset --keyFile keyfile

nohup: ignoring input and appending output to `nohup.out'
nohup: ignoring input and appending output to `nohup.out'
nohup: ignoring input and appending output to `nohup.out'

Waiting...
        localhost:30000: .......OK
        localhost:30001: ...................................OK
        localhost:30002: .OK

Connect to localhost:30000

Initialize the First Replica Set:

$ monogo localhost:30000/admin
mongo> db.runCommand( {'replSetInitiate': {'_id': 'firstset', 'members': [{'host': 'localhost:30000', '_id': 1}, {'host': 'localhost:30001', '_id': 2}, {'host': 'localhost:30002', '_id': 3}]}} )

Result:
{u'info': u'Config now saved locally.  Should come online in about a minute.', u'ok': 1.0}

All is done.

server info:
 $ mongo localhost:30000/admin -u account -p password --eval 'printjson(rs.status())'

shutdown servers:
 $ mongo localhost:30000/admin -u account -p password --eval 'db.shutdownServer()'
 $ mongo localhost:30001/admin -u account -p password --eval 'db.shutdownServer()'
 $ mongo localhost:30002/admin -u account -p password --eval 'db.shutdownServer()'