MongoDB健壮集群——用副本集做分片
1. MongoDB分片+副本集
健壮的集群方案
多个配置服务器 多个mongos服务器 每个片都是副本集 正确设置w
架构图
|
说明： 1. 此实验环境在一台机器上通过不同port和dbpath实现启动不同的mongod实例 2. 总的9个mongod实例，分别做成shard1、shard2、shard3三组副本集，每组1主2从 3. Mongos进程的数量不限，建议把mongos配置在每个应用服务器本机上，这样每个应用服务器就与自身的mongos进行通信，如果服务器不工作了，并不会影响其他的应用服务器与其自己的mongos通信 4. 此实验模拟2台应用服务器（2个mongos服务） 5. 生产环境中每个片都应该是副本集，这样单个服务器坏了，才不会导致片失效 |
部署环境
创建相关目录
[root@Master cluster2]# mkdir -p shard{,,}/node{,,}
[root@Master cluster2]# mkdir -p shard{,,}/logs
[root@Master cluster2]# ls shard*
shard1:
logs node1 node2 node3
shard2:
logs node1 node2 node3
shard3:
logs node1 node2 node3
[root@Master cluster2]# mkdir -p config/logs
[root@Master cluster2]# mkdir -p config/node{,,}
[root@Master cluster2]# ls config/
logs node1 node2 node3
[root@Master cluster2]# mkdir -p mongos/logs
启动配置服务
|
Config server |
/data/mongodb/config/node1 |
/data/mongodb/config/logs/node1.log |
10000 |
|
/data/mongodb/config/node2 |
/data/mongodb/config/logs/node2.log |
20000 |
|
|
/data/mongodb/config/node3 |
/data/mongodb/config/logs/node3.log |
30000 |
#按规划启动3个：跟启动单个配置服务一样，只是重复3次
[root@Master cluster2]# mongod --dbpath config/node1 --logpath config/logs/node1.log --logappend --fork --port
[root@Master cluster2]# mongod --dbpath config/node2 --logpath config/logs/node2.log --logappend --fork --port
[root@Master cluster2]# mongod --dbpath config/node3 --logpath config/logs/node3.log --logappend --fork --port
[root@Master cluster2]# ps -ef|grep mongod|grep -v grep
mongod : ? :: /usr/bin/mongod -f /etc/mongod.conf
root : ? :: mongod --dbpath config/node1 --logpath config/logs/node1.log --logappend --fork --port
root : ? :: mongod --dbpath config/node2 --logpath config/logs/node2.log --logappend --fork --port
root : ? :: mongod --dbpath config/node3 --logpath config/logs/node3.log --logappend --fork --port
启动路由服务
|
Mongos server |
—— |
/data/mongodb/mongos/logs/node1.log |
40000 |
|
—— |
/data/mongodb/mongos/logs/node2.log |
50000 |
#mongos的数量不受限制，通常应用一个服务器运行一个mongos
[root@Master cluster2]# mongos --port --configdb localhost:,localhost:,localhost: --logpath mongos/logs/mongos1.log --logappend --fork
[root@Master cluster2]# mongos --port --configdb localhost:,localhost:,localhost: --logpath mongos/logs/mongos1.log --logappend --fork
[root@Master cluster2]# ps -ef|grep mongos|grep -v grep
root : ? :: mongos --port --configdb localhost:,localhost:,localhost: --logpath mongos/logs/mongos1.log --logappend --fork
root : ? :: mongos --port --configdb localhost:,localhost:,localhost: --logpath mongos/logs/mongos1.log --logappend --fork
配置副本集
按规划，配置启动shard1、shard2、shard3三组副本集
#此处以shard1为例说明配置方法
#启动三个mongod进程
[root@Master cluster2]# mongod --replSet shard1 --dbpath shard1/node1 --logpath shard1/logs/node1.log --logappend --fork --port
[root@Master cluster2]# mongod --replSet shard1 --dbpath shard1/node2 --logpath shard1/logs/node2.log --logappend --fork --port
[root@Master cluster2]# mongod --replSet shard1 --dbpath shard1/node3 --logpath shard1/logs/node3.log --logappend --fork --port
#初始化Replica Set:shard1
[root@Master cluster2]# mongo --port
MongoDB shell version: 3.0.
connecting to: 127.0.0.1:/test
> use admin
switched to db admin
> rsconf={"_id" : "shard1","members" : [{"_id" : , "host" : "localhost:10001"}]}
{
"_id" : "shard1",
"members" : [
{
"_id" : ,
"host" : "localhost:10001"
}
]
}
> rs.initiate(rsconf)
{ "ok" : }
shard1:OTHER> rs.add("localhost:10002")
{ "ok" : }
shard1:PRIMARY> rs.add("localhost:10003")
{ "ok" : }
shard1:PRIMARY> rs.conf()
{
"_id" : "shard1",
"version" : ,
"members" : [
{
"_id" : ,
"host" : "localhost:10001",
"arbiterOnly" : false,
"buildIndexes" : true,
"hidden" : false,
"priority" : ,
"tags" : { },
"slaveDelay" : ,
"votes" :
},
{
"_id" : ,
"host" : "localhost:10002",
"arbiterOnly" : false,
"buildIndexes" : true,
"hidden" : false,
"priority" : ,
"tags" : { },
"slaveDelay" : ,
"votes" :
},
{
"_id" : ,
"host" : "localhost:10003",
"arbiterOnly" : false,
"buildIndexes" : true,
"hidden" : false,
"priority" : ,
"tags" : { },
"slaveDelay" : ,
"votes" :
}
],
"settings" : {
"chainingAllowed" : true,
"heartbeatTimeoutSecs" : ,
"getLastErrorModes" : { },
"getLastErrorDefaults" : {
"w" : ,
"wtimeout" :
}
}
}
Shard2和shard3同shard1配置副本集
[root@Master cluster2]# mongod --replSet shard2 --dbpath shard2/node1 --logpath shard2/logs/node1.log --logappend --fork --port
[root@Master cluster2]# mongod --replSet shard2 --dbpath shard2/node2 --logpath shard2/logs/node2.log --logappend --fork --port
[root@Master cluster2]# mongod --replSet shard2 --dbpath shard2/node3 --logpath shard2/logs/node3.log --logappend --fork --port
[root@Master cluster2]# mongo --port
> use admin
> rsconf={"_id" : "shard2","members" : [{"_id" : , "host" : "localhost:20001"}]}
> rs.initiate(rsconf)
shard2:OTHER> rs.add("localhost:20002")
shard2:PRIMARY> rs.add("localhost:20003")
shard2:PRIMARY> rs.conf()
{
"_id" : "shard2",
"version" : ,
"members" : [
{
"_id" : ,
"host" : "localhost:20001",
"arbiterOnly" : false,
"buildIndexes" : true,
"hidden" : false,
"priority" : ,
"tags" : { },
"slaveDelay" : ,
"votes" :
},
{
"_id" : ,
"host" : "localhost:20002",
"arbiterOnly" : false,
"buildIndexes" : true,
"hidden" : false,
"priority" : ,
"tags" : { },
"slaveDelay" : ,
"votes" :
},
{
"_id" : ,
"host" : "localhost:20003",
"arbiterOnly" : false,
"buildIndexes" : true,
"hidden" : false,
"priority" : ,
"tags" : { },
"slaveDelay" : ,
"votes" :
}
],
"settings" : {
"chainingAllowed" : true,
"heartbeatTimeoutSecs" : ,
"getLastErrorModes" : { },
"getLastErrorDefaults" : {
"w" : ,
"wtimeout" :
}
}
}
[root@Master cluster2]# mongod --replSet shard3 --dbpath shard3/node1 --logpath shard3/logs/node1.log --logappend --fork --port
[root@Master cluster2]# mongod --replSet shard3 --dbpath shard3/node2 --logpath shard3/logs/node2.log --logappend --fork --port
[root@Master cluster2]# mongod --replSet shard3 --dbpath shard3/node3 --logpath shard3/logs/node3.log --logappend --fork --port
[root@Master cluster2]# mongo --port
connecting to: 127.0.0.1:/test> use admin
> rsconf={"_id" : "shard3","members" : [{"_id" : , "host" : "localhost:30001"}]}
> rs.initiate(rsconf)
shard3:OTHER> rs.add("localhost:30002")
shard3:PRIMARY> rs.add("localhost:30003")
shard3:PRIMARY> rs.conf()
{
"_id" : "shard3",
"version" : ,
"members" : [
{
"_id" : ,
"host" : "localhost:30001",
"arbiterOnly" : false,
"buildIndexes" : true,
"hidden" : false,
"priority" : ,
"tags" : { },
"slaveDelay" : ,
"votes" :
},
{
"_id" : ,
"host" : "localhost:30002",
"arbiterOnly" : false,
"buildIndexes" : true,
"hidden" : false,
"priority" : ,
"tags" : { },
"slaveDelay" : ,
"votes" :
},
{
"_id" : ,
"host" : "localhost:30003",
"arbiterOnly" : false,
"buildIndexes" : true,
"hidden" : false,
"priority" : ,
"tags" : { },
"slaveDelay" : ,
"votes" :
}
],
"settings" : {
"chainingAllowed" : true,
"heartbeatTimeoutSecs" : ,
"getLastErrorModes" : { },
"getLastErrorDefaults" : {
"w" : ,
"wtimeout" :
}
}
}
添加（副本集）分片
#连接到mongs，并切换到admin这里必须连接路由节点
[root@Master cluster2]# mongo --port
MongoDB shell version: 3.0.
connecting to: 127.0.0.1:/test
mongos> use admin
switched to db admin
mongos> db.runCommand({"addShard":"shard1/localhost:10001"})
{ "shardAdded" : "shard1", "ok" : }
mongos> db.runCommand({"addShard":"shard2/localhost:20001"})
{ "shardAdded" : "shard2", "ok" : }
mongos> db.runCommand({"addShard":"shard3/localhost:30001"})
{ "shardAdded" : "shard3", "ok" : }
mongos> db.runCommand({listshards:})
{
"shards" : [
{
"_id" : "shard1",
"host" : "shard1/localhost:10001,localhost:10002,localhost:10003"
},
{
"_id" : "shard2",
"host" : "shard2/localhost:20001,localhost:20002,localhost:20003"
},
{
"_id" : "shard3",
"host" : "shard3/localhost:30001,localhost:30002,localhost:30003"
}
],
"ok" :
}
激活db和collections分片
激活数据库分片，命令
> db.runCommand( { enablesharding : "数据库名称"} );
执行以上命令，可以让数据库跨shard，如果不执行这步，数据库只会存放在一个shard
一旦激活数据库分片，数据库中不同的collection将被存放在不同的shard上
但一个collection仍旧存放在同一个shard上，要使单个collection也分片，还需单独对collection作些操作
#如：激活test数据库分片功能，连接mongos进程
[root@Master cluster2]# mongo --port
MongoDB shell version: 3.0.
connecting to: 127.0.0.1:/test
mongos> use admin
switched to db admin
mongos> db.runCommand({"enablesharding":"test"})
{ "ok" : }
要使单个collection也分片存储，需要给collection指定一个分片key，通过以下命令操作：
> db.runCommand( { shardcollection : "集合名称",key : "字段名称"});
注： a. 分片的collection系统会自动创建一个索引（也可用户提前创建好）
b. 分片的collection只能有一个在分片key上的唯一索引，其它唯一索引不被允许
#对collection：test.yujx分片
mongos> db.runCommand({"shardcollection":"test.yujx","key":{"_id":}})
{ "collectionsharded" : "test.yujx", "ok" : }
生成测试数据
mongos> use test
switched to db test
mongos> for(var i=;i<=;i++) db.yujx.save({"id":i,"a":,"b":,"c":})
WriteResult({ "nInserted" : })
mongos> db.yujx.count()
查看集合分片
mongos> db.yujx.stats()
{
"sharded" : true,
"paddingFactorNote" : "paddingFactor is unused and unmaintained in 3.0. It remains hard coded to 1.0 for compatibility only.",
"userFlags" : ,
"capped" : false,
"ns" : "test.yujx",
"count" : ,
"numExtents" : ,
"size" : ,
"storageSize" : ,
"totalIndexSize" : ,
"indexSizes" : {
"_id_" :
},
"avgObjSize" : ,
"nindexes" : ,
"nchunks" : ,
"shards" : {
"shard1" : {
"ns" : "test.yujx",
"count" : ,
"size" : ,
"avgObjSize" : ,
"numExtents" : ,
"storageSize" : ,
"lastExtentSize" : ,
"paddingFactor" : ,
"paddingFactorNote" : "paddingFactor is unused and unmaintained in 3.0. It remains hard coded to 1.0 for compatibility only.",
"userFlags" : ,
"capped" : false,
"nindexes" : ,
"totalIndexSize" : ,
"indexSizes" : {
"_id_" :
},
"ok" : ,
"$gleStats" : {
"lastOpTime" : Timestamp(, ),
"electionId" : ObjectId("55d15366716d7504d5d74c4c")
}
},
"shard2" : {
"ns" : "test.yujx",
"count" : ,
"size" : ,
"avgObjSize" : ,
"numExtents" : ,
"storageSize" : ,
"lastExtentSize" : ,
"paddingFactor" : ,
"paddingFactorNote" : "paddingFactor is unused and unmaintained in 3.0. It remains hard coded to 1.0 for compatibility only.",
"userFlags" : ,
"capped" : false,
"nindexes" : ,
"totalIndexSize" : ,
"indexSizes" : {
"_id_" :
},
"ok" : ,
"$gleStats" : {
"lastOpTime" : Timestamp(, ),
"electionId" : ObjectId("55d1543eabed7d6d4a71d25e")
}
},
"shard3" : {
"ns" : "test.yujx",
"count" : ,
"size" : ,
"avgObjSize" : ,
"numExtents" : ,
"storageSize" : ,
"lastExtentSize" : ,
"paddingFactor" : ,
"paddingFactorNote" : "paddingFactor is unused and unmaintained in 3.0. It remains hard coded to 1.0 for compatibility only.",
"userFlags" : ,
"capped" : false,
"nindexes" : ,
"totalIndexSize" : ,
"indexSizes" : {
"_id_" :
},
"ok" : ,
"$gleStats" : {
"lastOpTime" : Timestamp(, ),
"electionId" : ObjectId("55d155346f36550e3c5f062c")
}
}
},
"ok" :
}
查看数据库分片
mongos> db.printShardingStatus()
--- Sharding Status ---
sharding version: {
"_id" : ,
"minCompatibleVersion" : ,
"currentVersion" : ,
"clusterId" : ObjectId("55d152a35348652fbc726a10")
}
shards:
{ "_id" : "shard1", "host" : "shard1/localhost:10001,localhost:10002,localhost:10003" }
{ "_id" : "shard2", "host" : "shard2/localhost:20001,localhost:20002,localhost:20003" }
{ "_id" : "shard3", "host" : "shard3/localhost:30001,localhost:30002,localhost:30003" }
balancer:
Currently enabled: yes
Currently running: yes
Balancer lock taken at Sun Aug :: GMT- (PDT) by Master.Hadoop::::Balancer:
Failed balancer rounds in last attempts:
Migration Results for the last hours:
: Success
: Failed with error 'could not acquire collection lock for test.yujx to migrate chunk [{ : MinKey },{ : MaxKey }) :: caused by :: Lock for migrating chunk [{ : MinKey }, { : MaxKey }) in test.yujx is taken.', from shard1 to shard2
databases:
{ "_id" : "admin", "partitioned" : false, "primary" : "config" }
{ "_id" : "test", "partitioned" : true, "primary" : "shard1" }
test.yujx
shard key: { "_id" : }
chunks:
shard1
shard2
shard3
{ "_id" : { "$minKey" : } } -->> { "_id" : ObjectId("55d157cca0c90140e33a9342") } on : shard3 Timestamp(, )
{ "_id" : ObjectId("55d157cca0c90140e33a9342") } -->> { "_id" : ObjectId("55d157cca0c90140e33a934a") } on : shard1 Timestamp(, )
{ "_id" : ObjectId("55d157cca0c90140e33a934a") } -->> { "_id" : { "$maxKey" : } } on : shard2 Timestamp(, )
#或者连接mongos的config数据库查询
mongos> use config
switched to db config
mongos> db.shards.find()
{ "_id" : "shard1", "host" : "shard1/localhost:10001,localhost:10002,localhost:10003" }
{ "_id" : "shard2", "host" : "shard2/localhost:20001,localhost:20002,localhost:20003" }
{ "_id" : "shard3", "host" : "shard3/localhost:30001,localhost:30002,localhost:30003" }
mongos> db.databases.find()
{ "_id" : "admin", "partitioned" : false, "primary" : "config" }
{ "_id" : "test", "partitioned" : true, "primary" : "shard1" }
mongos> db.chunks.find()
{ "_id" : "test.yujx-_id_MinKey", "lastmod" : Timestamp(, ), "lastmodEpoch" : ObjectId("55d15738679c4d5f9108eba0"), "ns" : "test.yujx", "min" : { "_id" : { "$minKey" : } }, "max" : { "_id" : ObjectId("55d157cca0c90140e33a9342") }, "shard" : "shard3" }
{ "_id" : "test.yujx-_id_ObjectId('55d157cca0c90140e33a9342')", "lastmod" : Timestamp(, ), "lastmodEpoch" : ObjectId("55d15738679c4d5f9108eba0"), "ns" : "test.yujx", "min" : { "_id" : ObjectId("55d157cca0c90140e33a9342") }, "max" : { "_id" : ObjectId("55d157cca0c90140e33a934a") }, "shard" : "shard1" }
{ "_id" : "test.yujx-_id_ObjectId('55d157cca0c90140e33a934a')", "lastmod" : Timestamp(, ), "lastmodEpoch" : ObjectId("55d15738679c4d5f9108eba0"), "ns" : "test.yujx", "min" : { "_id" : ObjectId("55d157cca0c90140e33a934a") }, "max" : { "_id" : { "$maxKey" : } }, "shard" : "shard2" }
hash分片
MongoDB2.4以上的版本支持基于哈希的分片
mongos> use admin
mongos> db.runCommand({"enablesharding":"mydb"})
mongos> db.runCommand({"shardcollection":"mydb.mycollection","key":{"_id":"hashed"}})
mongos> use mydb
switched to db mydb
mongos> for(i=;i<;i++){ db.mycollection.insert({"Uid":i,"Name":"zhanjindong2","Age":,"Date":new Date()}); }
WriteResult({ "nInserted" : })
mongos> db.mycollection.stats()
{
"sharded" : true,
"paddingFactorNote" : "paddingFactor is unused and unmaintained in 3.0. It remains hard coded to 1.0 for compatibility only.",
"userFlags" : ,
"capped" : false,
"ns" : "mydb.mycollection",
"count" : ,
"numExtents" : ,
"size" : ,
"storageSize" : ,
"totalIndexSize" : ,
"indexSizes" : {
"_id_" : ,
"_id_hashed" :
},
"avgObjSize" : ,
"nindexes" : ,
"nchunks" : ,
"shards" : {
"shard1" : {
"ns" : "mydb.mycollection",
"count" : ,
"size" : ,
"avgObjSize" : ,
"numExtents" : ,
"storageSize" : ,
"lastExtentSize" : ,
"paddingFactor" : ,
"paddingFactorNote" : "paddingFactor is unused and unmaintained in 3.0. It remains hard coded to 1.0 for compatibility only.",
"userFlags" : ,
"capped" : false,
"nindexes" : ,
"totalIndexSize" : ,
"indexSizes" : {
"_id_" : ,
"_id_hashed" :
},
"ok" : ,
"$gleStats" : {
"lastOpTime" : Timestamp(, ),
"electionId" : ObjectId("55d15366716d7504d5d74c4c")
}
},
"shard2" : {
"ns" : "mydb.mycollection",
"count" : ,
"size" : ,
"avgObjSize" : ,
"numExtents" : ,
"storageSize" : ,
"lastExtentSize" : ,
"paddingFactor" : ,
"paddingFactorNote" : "paddingFactor is unused and unmaintained in 3.0. It remains hard coded to 1.0 for compatibility only.",
"userFlags" : ,
"capped" : false,
"nindexes" : ,
"totalIndexSize" : ,
"indexSizes" : {
"_id_" : ,
"_id_hashed" :
},
"ok" : ,
"$gleStats" : {
"lastOpTime" : Timestamp(, ),
"electionId" : ObjectId("55d1543eabed7d6d4a71d25e")
}
},
"shard3" : {
"ns" : "mydb.mycollection",
"count" : ,
"size" : ,
"avgObjSize" : ,
"numExtents" : ,
"storageSize" : ,
"lastExtentSize" : ,
"paddingFactor" : ,
"paddingFactorNote" : "paddingFactor is unused and unmaintained in 3.0. It remains hard coded to 1.0 for compatibility only.",
"userFlags" : ,
"capped" : false,
"nindexes" : ,
"totalIndexSize" : ,
"indexSizes" : {
"_id_" : ,
"_id_hashed" :
},
"ok" : ,
"$gleStats" : {
"lastOpTime" : Timestamp(, ),
"electionId" : ObjectId("55d155346f36550e3c5f062c")
}
}
},
"ok" :
}
单点故障分析
由于这是为了了解入门mongodb做的实验，而故障模拟太浪费时间，所以这里就不一一列出，关于故障场景分析，可以参考：
http://blog.itpub.net/27000195/viewspace-1404402/
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