一、Replica Set 集群分为两种架构：
- 奇数个节点构成Replica Set，所有节点拥有数据集。最小架构: 1个Primary节点，2个Secondary节点
- 偶数个节点 + 一个仲裁节点 构成的Replica Set，节点拥有数据集，仲裁节点仅参与仲裁选举出Primary节点。 最小架构：1个Primary节点，1个Secondary节点，1个Arbiter节点
-
接下来就以3台服务器为例，部署具有仲裁的框架。
二、安装部署（请访问 "MongoDB安装"）https://www.558idc.com/Linux/2019-07/159249.htm
Primary的配置文件：
systemLog: destination: file path: "/data/mongodb/log/mongod.log" logAppend: true storage: dbPath: "/data/mongodb/data" journal: enabled: true wiredTiger: engineConfig: cacheSizeGB: 2 processManagement: fork: true pidFilePath: "/data/mongodb/pid/m.pid" net: bindIp: 10.10.18.10 port: 27017
replication: replSetName: "rs0"
Secondary的配置文件
systemLog: destination: file path: "/data/mongodb/log/mongod.log" logAppend: true storage: dbPath: "/data/mongodb/data" journal: enabled: true wiredTiger: engineConfig: cacheSizeGB: 2 processManagement: fork: true pidFilePath: "/data/mongodb/pid/m.pid" net: bindIp: 10.10.18.11 port: 27017
replication: replSetName: "rs0"
Arbiter的配置文件
systemLog: destination: file path: "/data/mongodb/log/mongod.log" logAppend: true storage: dbPath: "/data/mongodb/data" journal: enabled: true wiredTiger: engineConfig: cacheSizeGB: 2 processManagement: fork: true pidFilePath: "/data/mongodb/pid/m.pid" net: bindIp: 10.10.18.12 port: 27017
replication: replSetName: "rs0"
启动三台服务器上的mongdb
mongod -f /data/mongodb/mongod.conf
关闭进程
mongod -f /data/mongodb/mongod.conf --shutdown
三、配置Replica Set
登录三台服务器中任意一台，登录mongo（如果报错就将配置文件中：security 内容暂时先去掉）
mongo --host 10.10.18.10
>cfg={ _id:"rs0",members:[{_id:0,host:'10.10.18.10:27017',priority:1},{_id:1,host:'10.10.18.11:27017',priority:1},{_id:2,host:'10.10.18.12:27017',arbiterOnly:true}] };
>rs.initiate(cfg)
查看Replica Set配置
> rs.conf()
{
"_id" : "rs0",
"version" : 1,
"protocolVersion" : NumberLong(1),
"writeConcernMajorityJournalDefault" : true,
"members" : [
{
"_id" : 0,
"host" : "10.10.18.10:27017",
"arbiterOnly" : false,
"buildIndexes" : true,
"hidden" : false,
"priority" : 1,
"tags" : {
},
"slaveDelay" : NumberLong(0),
"votes" : 1
},
{
"_id" : 1,
"host" : "10.10.18.11:27017",
"arbiterOnly" : false,
"buildIndexes" : true,
"hidden" : false,
"priority" : 1,
"tags" : {
},
"slaveDelay" : NumberLong(0),
"votes" : 1
},
{
"_id" : 2,
"host" : "10.10.18.12:27017",
"arbiterOnly" : true,
"buildIndexes" : true,
"hidden" : false,
"priority" : 0,
"tags" : {
},
"slaveDelay" : NumberLong(0),
"votes" : 1
}
],
"settings" : {
"chainingAllowed" : true,
"heartbeatIntervalMillis" : 2000,
"heartbeatTimeoutSecs" : 10,
"electionTimeoutMillis" : 10000,
"catchUpTimeoutMillis" : -1,
"catchUpTakeoverDelayMillis" : 30000,
"getLastErrorModes" : {
},
"getLastErrorDefaults" : {
"w" : 1,
"wtimeout" : 0
},
"replicaSetId" : ObjectId("5cff76e5e57e23a5bc7054e2")
}
}
四、验证Replica Set
在Primary中插入数据
rs0:PRIMARY> show dbs admin 0.000GB config 0.000GB local 0.000GB rs0:PRIMARY> db.users.insertOne( ... { ... name:"sue", ... age: 26, ... status:"pending" ... }) { "acknowledged" : true, "insertedId" : ObjectId("5cff79e8993e70290a081d04") }
rs0:PRIMARY> db.users.find()
{ "_id" : ObjectId("5cff79e8993e70290a081d04"), "name" : "sue", "age" : 26, "status" : "pending" }
在Secondary中，默认是不允许读
rs0:SECONDARY> db.users.find() Error: error: { "operationTime" : Timestamp(1560247181, 1), "ok" : 0, "errmsg" : "not master and slaveOk=false", "code" : 13435, "codeName" : "NotMasterNoSlaveOk", "$clusterTime" : { "clusterTime" : Timestamp(1560247181, 1), "signature" : { "hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="), "keyId" : NumberLong(0) } } }
五、创建用户 https://www.558idc.com/Linux/2019-07/159238.htm
六、故障模拟
停止Primary上的mongo进程，在Secondary上登录mongo查看
mongo --host 10.10.18.11
rs0:PRIMARY> db.users.find() { "_id" : ObjectId("5cff79e8993e70290a081d04"), "name" : "sue", "age" : 26, "status" : "pending" }
发现原Secondary变成Primary，并且可以进行查询。
开启原Primary服务器上的mongo进程，该服务器变成了Secondary。
七、数据备份和恢复
mongodump从MongoDB中读取数据，保存为BSON文件，mongorestore读取BSON文件恢复到MongoDB中。适用于小型MongoDB的备份和恢复。
mongodump备份的时候只备份MongoDB中的文档，使用mongorestore恢复之后需要重建索引
mongodump --host 10.10.18.11 --port 27017 --username myUserAdmin --password abc123 --gzip --out /data/mongobak/$(date +%F)
注：--oplog 表示备份的时候oplog.bson文件，存放在dump开始 到 dump结束之间所有的oplog。
根据前面的备份恢复到一个新的Replica Set集群中其中一台服务器上。
恢复
恢复的过程中，不要启用认证。否则在将其他机器加入到Replica Set集群中来的时候，会出现无法认证的问题。
1、首先在一台服务器上开启一个干净mongo服务（无任何数据），做为 Primary
mongd.conf配置文件内容
systemLog: destination: file path: "/data/mongodb/log/mongod.log" logAppend: true storage: dbPath: "/data/mongodb/data" journal: enabled: true wiredTiger: engineConfig: cacheSizeGB: 2 processManagement: fork: true pidFilePath: "/data/mongodb/pid/mongod.pid" net: bindIp: 10.10.18.10 port: 27017 replication: replSetName: "rs0"
2、开启mongod服务
/data/mongodb/bin/mongod -f /data/mongodb/mongod.conf
3、创建单个Replica Set
登录mongo，然后创建单个Replica Set
mongo --host 10.10.18.10 > cfg={_id:"rs0",members:[{_id:0,host:'10.10.18.10:27017',priority:1}]}
> rs.initiate(cfg)
创建结果：
{
"ok" : 1,
"operationTime" : Timestamp(1560394449, 1),
"$clusterTime" : {
"clusterTime" : Timestamp(1560394449, 1),
"signature" : {
"hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
"keyId" : NumberLong(0)
}
}
}
创建好了之后，就可以查看当前的数据库
rs0:SECONDARY> show dbs admin 0.000GB config 0.000GB local 0.000GB
可以发现，目前就三个基本的数据库。
4、恢复数据
mongorestore --host 10.10.18.10 --port 27017 --gzip /data/mongobak/2019-06-12
结果
2019-06-13T10:55:33.817+0800 preparing collections to restore from
2019-06-13T10:55:33.829+0800 reading metadata for admin.test from /data/mongobak/2019-06-12/admin/test.metadata.json.gz
2019-06-13T10:55:33.832+0800 reading metadata for test.users from /data/mongobak/2019-06-12/test/users.metadata.json.gz
2019-06-13T10:55:33.834+0800 reading metadata for reporting.reporting from /data/mongobak/2019-06-12/reporting/reporting.metadata.json.gz
2019-06-13T10:55:33.841+0800 reading metadata for admin.reporting from /data/mongobak/2019-06-12/admin/reporting.metadata.json.gz
2019-06-13T10:55:33.861+0800 restoring test.users from /data/mongobak/2019-06-12/test/users.bson.gz
2019-06-13T10:55:34.085+0800 restoring admin.test from /data/mongobak/2019-06-12/admin/test.bson.gz
2019-06-13T10:55:34.123+0800 no indexes to restore
2019-06-13T10:55:34.123+0800 finished restoring test.users (1 document)
2019-06-13T10:55:34.123+0800 restoring admin.reporting from /data/mongobak/2019-06-12/admin/reporting.bson.gz
2019-06-13T10:55:34.175+0800 restoring reporting.reporting from /data/mongobak/2019-06-12/reporting/reporting.bson.gz
2019-06-13T10:55:34.230+0800 no indexes to restore
2019-06-13T10:55:34.230+0800 finished restoring admin.test (2 documents)
2019-06-13T10:55:34.233+0800 no indexes to restore
2019-06-13T10:55:34.233+0800 finished restoring reporting.reporting (1 document)
2019-06-13T10:55:34.234+0800 no indexes to restore
2019-06-13T10:55:34.234+0800 finished restoring admin.reporting (1 document)
2019-06-13T10:55:34.234+0800 restoring users from /data/mongobak/2019-06-12/admin/system.users.bson.gz
2019-06-13T10:55:34.312+0800 done
恢复完成，在登录mongo查看，恢复数据库的情况。
rs0:PRIMARY> show dbs
admin 0.000GB
config 0.000GB
local 0.000GB
reporting 0.000GB
test 0.000GB
rs0:PRIMARY> use test
switched to db test
rs0:PRIMARY> show collections
users
rs0:PRIMARY> db.users.find()
{ "_id" : ObjectId("5cff79e8993e70290a081d04"), "name" : "sue", "age" : 26, "status" : "pending" }
可以看出之前的记录已经恢复了。
注意：如果备份时，MongoDB是拥有用户名和密码才能进行登录的，在恢复之后，用户名和密码也是可以使用的。如果需要在使用认证登录，需要将下面信息添加的配置文件mongod.conf：
security: keyFile: "/data/mongodb/keyfile" authorization: "enabled"
然后重启mongo服务。
5、关闭刚恢复的MongoDB，将数据目录同步到另一台服务器上，作为Secondary
通过之前，确认该台服务器上的mongo是无任何数据。将Primary服务上的 /data/mongodb/data 同步到 Secondary服务器上 /data/mongodb/data
6、依次开启Primary、Secondary、Arbiter的mongo服务
7、在Primary服务器上，将Secondary、Arbiter加入到Replica Set集群中来
查看当前Replica Set集群的配置
rs0:PRIMARY> rs.conf() { "_id" : "rs0", "version" : 1, "protocolVersion" : NumberLong(1), "writeConcernMajorityJournalDefault" : true, "members" : [ { "_id" : 0, "host" : "10.10.18.10:27017", "arbiterOnly" : false, "buildIndexes" : true, "hidden" : false, "priority" : 1, "tags" : { }, "slaveDelay" : NumberLong(0), "votes" : 1 } ], "settings" : { "chainingAllowed" : true, "heartbeatIntervalMillis" : 2000, "heartbeatTimeoutSecs" : 10, "electionTimeoutMillis" : 10000, "catchUpTimeoutMillis" : -1, "catchUpTakeoverDelayMillis" : 30000, "getLastErrorModes" : { }, "getLastErrorDefaults" : { "w" : 1, "wtimeout" : 0 }, "replicaSetId" : ObjectId("5d01bad15dfd3f294d147b36") } }
可以看到当前Replica Set集群中就一台服务器
将Secondary、Arbiter加入到Replica Set集群中
rs0:PRIMARY> rs.add( ... { ... _id: 1, ... host:'10.10.18.11:27017', ... priority:1 ... } ... ) { "ok" : 1, "operationTime" : Timestamp(1560397822, 1), "$clusterTime" : { "clusterTime" : Timestamp(1560397822, 1), "signature" : { "hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="), "keyId" : NumberLong(0) } } } rs0:PRIMARY> rs.add( ... { ... _id: 2, ... host:'10.10.18.12:27017', ... arbiterOnly:true ... } ... ) { "ok" : 1, "operationTime" : Timestamp(1560397830, 1), "$clusterTime" : { "clusterTime" : Timestamp(1560397830, 1), "signature" : { "hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="), "keyId" : NumberLong(0) }
再次查看状态：
rs0:PRIMARY> rs.conf() { "_id" : "rs0", "version" : 3, "protocolVersion" : NumberLong(1), "writeConcernMajorityJournalDefault" : true, "members" : [ { "_id" : 0, "host" : "10.10.18.10:27017", "arbiterOnly" : false, "buildIndexes" : true, "hidden" : false, "priority" : 1, "tags" : { }, "slaveDelay" : NumberLong(0), "votes" : 1 }, { "_id" : 1, "host" : "10.10.18.11:27017", "arbiterOnly" : false, "buildIndexes" : true, "hidden" : false, "priority" : 1, "tags" : { }, "slaveDelay" : NumberLong(0), "votes" : 1 }, { "_id" : 2, "host" : "10.10.18.12:27017", "arbiterOnly" : true, "buildIndexes" : true, "hidden" : false, "priority" : 0, "tags" : { }, "slaveDelay" : NumberLong(0), "votes" : 1 } ], "settings" : { "chainingAllowed" : true, "heartbeatIntervalMillis" : 2000, "heartbeatTimeoutSecs" : 10, "electionTimeoutMillis" : 10000, "catchUpTimeoutMillis" : -1, "catchUpTakeoverDelayMillis" : 30000, "getLastErrorModes" : { }, "getLastErrorDefaults" : { "w" : 1, "wtimeout" : 0 }, "replicaSetId" : ObjectId("5d01bad15dfd3f294d147b36") } }
加入成功。
开启认证访问
在三台服务器的配置文件中添加：
security: keyFile: "/data/mongodb/keyfile" authorization: "enabled"
然后依次关闭：Arbiter Secondary Primary
依次开启：Primary Secondary Arbiter
security: keyFile: "/data/mongodb/keyfile" authorization: "enabled"