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通过docker-compose搭建mongo的replica set高可用

2022年07月19日123落叶无声

通过docker-compose搭建mongo的replica set高可用

前言

搭建一个mongo的集群,同时原来单机mongo的数据需要迁移到集群中。

处理思路:单机mongo的数据通过mongodump备份,然后集群搭建起来了,在mongorestore导入到集群中,实现数据的迁移。

备份数据

备份(mongodump)与恢复(mongorestore)

备份数据到本地

mongodump -h 192.168.56.201:37018 -u handle -p jimeng2017 -o /home/liz/Desktop/mongo-bei

数据恢复

新的集群安装完成之后,恢复数据到Primary节点,集群会自动同步到副本集中

mongorestore -h 192.168.56.201:37017 -u handle -p jimeng2017  /home/liz/Desktop/mongo-bei 

注意:更换自己服务器上面的ip和mongo对应的账号密码

集群搭建

生成keyFile

  • MongoDB使用keyfile认证,副本集中的每个mongod实例使用keyfile内容作为认证其他成员的共享密码。mongod实例只有拥有正确的keyfile才可以加入副本集。
  • keyFile的内容必须是6到1024个字符的长度,且副本集所有成员的keyFile内容必须相同。
  • 有一点要注意是的:在UNIX系统中,keyFile必须没有组权限或完全权限(也就是权限要设置成X00的形式)。Windows系统中,keyFile权限没有被检查。
  • 可以使用任意方法生成keyFile。例如,如下操作使用openssl生成复杂的随机的1024个字符串。然后使用chmod修改文件权限,只给文件拥有者提供读权限。
# 400权限是要保证安全性,否则mongod启动会报错 
openssl rand -base64 756 > mongodb.key 
chmod 400 mongodb.key 

每一个副本集成员都要使用相同的keyFile文件

创建yml文件

配置文件:

version: '3.3' 
 
services: 
  mongodb1: 
    image: mongo:4.2.1 
    volumes: 
      - /data/mongo/data/mongo1:/data/db 
      - ./mongodb.key:/data/mongodb.key 
    user: root 
    environment: 
      - MONGO_INITDB_ROOT_USERNAME=handle 
      - MONGO_INITDB_ROOT_PASSWORD=jimeng2017 
      - MONGO_INITDB_DATABASE=handle 
    container_name: mongodb1 
    ports: 
      - 37017:27017 
    command: mongod --replSet mongos --keyFile /data/mongodb.key 
    restart: always 
    entrypoint: 
      - bash 
      - -c 
      - | 
        chmod 400 /data/mongodb.key 
        chown 999:999 /data/mongodb.key 
        exec docker-entrypoint.sh $$@ 
 
  mongodb2: 
    image: mongo:4.2.1 
    volumes: 
      - /data/mongo/data/mongo2:/data/db 
      - ./mongodb.key:/data/mongodb.key 
    user: root 
    environment: 
      - MONGO_INITDB_ROOT_USERNAME=handle 
      - MONGO_INITDB_ROOT_PASSWORD=jimeng2017 
      - MONGO_INITDB_DATABASE=handle 
    container_name: mongodb2 
    ports: 
      - 37018:27017 
    command: mongod --replSet mongos --keyFile /data/mongodb.key 
    restart: always 
    entrypoint: 
      - bash 
      - -c 
      - | 
        chmod 400 /data/mongodb.key 
        chown 999:999 /data/mongodb.key 
        exec docker-entrypoint.sh $$@ 
 
  mongodb3: 
    image: mongo:4.2.1 
    volumes: 
      - /data/mongo/data/mongo3:/data/db 
      - ./mongodb.key:/data/mongodb.key 
    user: root 
    environment: 
      - MONGO_INITDB_ROOT_USERNAME=handle 
      - MONGO_INITDB_ROOT_PASSWORD=jimeng2017 
      - MONGO_INITDB_DATABASE=handle 
    container_name: mongodb3 
    ports: 
      - 37019:27017 
    command: mongod --replSet mongos --keyFile /data/mongodb.key 
    restart: always 
    entrypoint: 
      - bash 
      - -c 
      - | 
        chmod 400 /data/mongodb.key 
        chown 999:999 /data/mongodb.key 
        exec docker-entrypoint.sh $$@ 

文件详解
chown 999:999 /data/mongodb.key 999用户是容器中的mongod用户,通过chown修改文件用户权限
mongod --replSet mongos --keyFile /data/mongodb.key 启动命令,--replSet mongos 以副本集形式启动并将副本集名字命名为 mongos ,--keyFile /data/mongodb.key 设置keyFile,用于副本集通信,文件通过 volumes 映射到容器内

然后启动

docker-compose -f  docker-compose-set.yml up -d 

初始化副本集

然后进去到第一个容器里面,初始化副本集

docker exec -it mongodb1 /bin/bash 

登录

mongo -u 账号 -p 密码 

登录成功可以查看状态

> rs.status() 
{ 
	"ok" : 0, 
	"errmsg" : "no replset config has been received", 
	"code" : 94, 
	"codeName" : "NotYetInitialized" 
} 

配置副本集

> rs.initiate({ 
... ...     _id: "mongos", 
... ...     members: [ 
... ...         { _id : 0, host : "192.168.56.201:37017" }, 
... ...         { _id : 1, host : "192.168.56.201:37018" }, 
... ...         { _id : 2, host : "192.168.56.201:37019" } 
... ...     ] 
... ... }); 
{ "ok" : 1 } 
 

上面提示ok就是表示成功了,这时候会选举出Primary节点。重新通过rs.status()查看状态就能看到了。

rs.status() 
{ 
	"set" : "mongos", 
	"date" : ISODate("2020-07-04T13:02:44.676Z"), 
	"myState" : 1, 
	"term" : NumberLong(1), 
	"syncingTo" : "", 
	"syncSourceHost" : "", 
	"syncSourceId" : -1, 
	"heartbeatIntervalMillis" : NumberLong(2000), 
	"majorityVoteCount" : 2, 
	"writeMajorityCount" : 2, 
	"optimes" : { 
		"lastCommittedOpTime" : { 
			"ts" : Timestamp(1593867760, 1), 
			"t" : NumberLong(1) 
		}, 
		"lastCommittedWallTime" : ISODate("2020-07-04T13:02:40.809Z"), 
		"readConcernMajorityOpTime" : { 
			"ts" : Timestamp(1593867760, 1), 
			"t" : NumberLong(1) 
		}, 
		"readConcernMajorityWallTime" : ISODate("2020-07-04T13:02:40.809Z"), 
		"appliedOpTime" : { 
			"ts" : Timestamp(1593867760, 1), 
			"t" : NumberLong(1) 
		}, 
		"durableOpTime" : { 
			"ts" : Timestamp(1593867760, 1), 
			"t" : NumberLong(1) 
		}, 
		"lastAppliedWallTime" : ISODate("2020-07-04T13:02:40.809Z"), 
		"lastDurableWallTime" : ISODate("2020-07-04T13:02:40.809Z") 
	}, 
	"lastStableRecoveryTimestamp" : Timestamp(1593867720, 5), 
	"lastStableCheckpointTimestamp" : Timestamp(1593867720, 5), 
	"electionCandidateMetrics" : { 
		"lastElectionReason" : "electionTimeout", 
		"lastElectionDate" : ISODate("2020-07-04T13:02:00.300Z"), 
		"termAtElection" : NumberLong(1), 
		"lastCommittedOpTimeAtElection" : { 
			"ts" : Timestamp(0, 0), 
			"t" : NumberLong(-1) 
		}, 
		"lastSeenOpTimeAtElection" : { 
			"ts" : Timestamp(1593867709, 1), 
			"t" : NumberLong(-1) 
		}, 
		"numVotesNeeded" : 2, 
		"priorityAtElection" : 1, 
		"electionTimeoutMillis" : NumberLong(10000), 
		"numCatchUpOps" : NumberLong(-29631936), 
		"newTermStartDate" : ISODate("2020-07-04T13:02:00.787Z"), 
		"wMajorityWriteAvailabilityDate" : ISODate("2020-07-04T13:02:01.528Z") 
	}, 
	"members" : [ 
		{ 
			"_id" : 0, 
			"name" : "192.168.56.201:37017", 
			"ip" : "192.168.56.201", 
			"health" : 1, 
			"state" : 1, 
			"stateStr" : "PRIMARY", 
			"uptime" : 155, 
			"optime" : { 
				"ts" : Timestamp(1593867760, 1), 
				"t" : NumberLong(1) 
			}, 
			"optimeDate" : ISODate("2020-07-04T13:02:40Z"), 
			"syncingTo" : "", 
			"syncSourceHost" : "", 
			"syncSourceId" : -1, 
			"infoMessage" : "could not find member to sync from", 
			"electionTime" : Timestamp(1593867720, 1), 
			"electionDate" : ISODate("2020-07-04T13:02:00Z"), 
			"configVersion" : 1, 
			"self" : true, 
			"lastHeartbeatMessage" : "" 
		}, 
		{ 
			"_id" : 1, 
			"name" : "192.168.56.201:37018", 
			"ip" : "192.168.56.201", 
			"health" : 1, 
			"state" : 2, 
			"stateStr" : "SECONDARY", 
			"uptime" : 54, 
			"optime" : { 
				"ts" : Timestamp(1593867760, 1), 
				"t" : NumberLong(1) 
			}, 
			"optimeDurable" : { 
				"ts" : Timestamp(1593867760, 1), 
				"t" : NumberLong(1) 
			}, 
			"optimeDate" : ISODate("2020-07-04T13:02:40Z"), 
			"optimeDurableDate" : ISODate("2020-07-04T13:02:40Z"), 
			"lastHeartbeat" : ISODate("2020-07-04T13:02:44.402Z"), 
			"lastHeartbeatRecv" : ISODate("2020-07-04T13:02:43.511Z"), 
			"pingMs" : NumberLong(0), 
			"lastHeartbeatMessage" : "", 
			"syncingTo" : "192.168.56.201:37017", 
			"syncSourceHost" : "192.168.56.201:37017", 
			"syncSourceId" : 0, 
			"infoMessage" : "", 
			"configVersion" : 1 
		}, 
		{ 
			"_id" : 2, 
			"name" : "192.168.56.201:37019", 
			"ip" : "192.168.56.201", 
			"health" : 1, 
			"state" : 2, 
			"stateStr" : "SECONDARY", 
			"uptime" : 54, 
			"optime" : { 
				"ts" : Timestamp(1593867760, 1), 
				"t" : NumberLong(1) 
			}, 
			"optimeDurable" : { 
				"ts" : Timestamp(1593867760, 1), 
				"t" : NumberLong(1) 
			}, 
			"optimeDate" : ISODate("2020-07-04T13:02:40Z"), 
			"optimeDurableDate" : ISODate("2020-07-04T13:02:40Z"), 
			"lastHeartbeat" : ISODate("2020-07-04T13:02:44.402Z"), 
			"lastHeartbeatRecv" : ISODate("2020-07-04T13:02:43.533Z"), 
			"pingMs" : NumberLong(0), 
			"lastHeartbeatMessage" : "", 
			"syncingTo" : "192.168.56.201:37017", 
			"syncSourceHost" : "192.168.56.201:37017", 
			"syncSourceId" : 0, 
			"infoMessage" : "", 
			"configVersion" : 1 
		} 
	], 
	"ok" : 1, 
	"$clusterTime" : { 
		"clusterTime" : Timestamp(1593867760, 1), 
		"signature" : { 
			"hash" : BinData(0,"Zr91geLBqJM7xN3vVVMWnJYAexk="), 
			"keyId" : NumberLong("6845609731550085123") 
		} 
	}, 
	"operationTime" : Timestamp(1593867760, 1) 
} 

通过rs.status()的输出我们就能分出那个是PRIMARY节点了。

增加副本集

之前已经初始化了三个mongo,我们在原来的基础上再增加一个副本集。

首先编写docker-compose-set.yml增加mongodb4

mongodb4: 
    image: mongo:4.2.1 
    volumes: 
      - /data/mongo/data/mongo4:/data/db 
      - ./mongodb.key:/data/mongodb.key 
    user: root 
    environment: 
      - MONGO_INITDB_ROOT_USERNAME=handle 
      - MONGO_INITDB_ROOT_PASSWORD=jimeng2017 
      - MONGO_INITDB_DATABASE=handle 
    container_name: mongodb4 
    ports: 
      - 37020:27017 
    command: mongod --replSet mongos --keyFile /data/mongodb.key 
    restart: always 
    entrypoint: 
      - bash 
      - -c 
      - | 
        chmod 400 /data/mongodb.key 
        chown 999:999 /data/mongodb.key 
        exec docker-entrypoint.sh $$@ 

启动

docker-compose -f  docker-compose-set.yml up -d 

然后进入到PRIMARY,执行

> rs.add("192.168.56.201:37020") 
{ 
	"ok" : 1, 
	"$clusterTime" : { 
		"clusterTime" : Timestamp(1593868399, 1), 
		"signature" : { 
			"hash" : BinData(0,"BZJ2tCwFE1NvE22/LwGzFTWy+1M="), 
			"keyId" : NumberLong("6845609731550085123") 
		} 
	}, 
	"operationTime" : Timestamp(1593868399, 1) 
} 

再次查看

> rs.status() 
{ 
	"set" : "mongos", 
	"date" : ISODate("2020-07-04T13:13:27.944Z"), 
	"myState" : 1, 
	"term" : NumberLong(3), 
	"syncingTo" : "", 
	"syncSourceHost" : "", 
	"syncSourceId" : -1, 
	"heartbeatIntervalMillis" : NumberLong(2000), 
	"majorityVoteCount" : 3, 
	"writeMajorityCount" : 3, 
	"optimes" : { 
		"lastCommittedOpTime" : { 
			"ts" : Timestamp(1593868399, 1), 
			"t" : NumberLong(3) 
		}, 
		"lastCommittedWallTime" : ISODate("2020-07-04T13:13:19.243Z"), 
		"readConcernMajorityOpTime" : { 
			"ts" : Timestamp(1593868399, 1), 
			"t" : NumberLong(3) 
		}, 
		"readConcernMajorityWallTime" : ISODate("2020-07-04T13:13:19.243Z"), 
		"appliedOpTime" : { 
			"ts" : Timestamp(1593868399, 1), 
			"t" : NumberLong(3) 
		}, 
		"durableOpTime" : { 
			"ts" : Timestamp(1593868399, 1), 
			"t" : NumberLong(3) 
		}, 
		"lastAppliedWallTime" : ISODate("2020-07-04T13:13:19.243Z"), 
		"lastDurableWallTime" : ISODate("2020-07-04T13:13:19.243Z") 
	}, 
	"lastStableRecoveryTimestamp" : Timestamp(1593868366, 1), 
	"lastStableCheckpointTimestamp" : Timestamp(1593868366, 1), 
	"electionCandidateMetrics" : { 
		"lastElectionReason" : "electionTimeout", 
		"lastElectionDate" : ISODate("2020-07-04T13:06:06.408Z"), 
		"termAtElection" : NumberLong(3), 
		"lastCommittedOpTimeAtElection" : { 
			"ts" : Timestamp(0, 0), 
			"t" : NumberLong(-1) 
		}, 
		"lastSeenOpTimeAtElection" : { 
			"ts" : Timestamp(1593867860, 1), 
			"t" : NumberLong(1) 
		}, 
		"numVotesNeeded" : 2, 
		"priorityAtElection" : 1, 
		"electionTimeoutMillis" : NumberLong(10000), 
		"numCatchUpOps" : NumberLong(37018), 
		"newTermStartDate" : ISODate("2020-07-04T13:06:06.753Z"), 
		"wMajorityWriteAvailabilityDate" : ISODate("2020-07-04T13:06:07.255Z") 
	}, 
	"members" : [ 
		{ 
			"_id" : 0, 
			"name" : "192.168.56.201:37017", 
			"ip" : "192.168.56.201", 
			"health" : 1, 
			"state" : 2, 
			"stateStr" : "SECONDARY", 
			"uptime" : 452, 
			"optime" : { 
				"ts" : Timestamp(1593868399, 1), 
				"t" : NumberLong(3) 
			}, 
			"optimeDurable" : { 
				"ts" : Timestamp(1593868399, 1), 
				"t" : NumberLong(3) 
			}, 
			"optimeDate" : ISODate("2020-07-04T13:13:19Z"), 
			"optimeDurableDate" : ISODate("2020-07-04T13:13:19Z"), 
			"lastHeartbeat" : ISODate("2020-07-04T13:13:27.642Z"), 
			"lastHeartbeatRecv" : ISODate("2020-07-04T13:13:27.493Z"), 
			"pingMs" : NumberLong(0), 
			"lastHeartbeatMessage" : "", 
			"syncingTo" : "", 
			"syncSourceHost" : "", 
			"syncSourceId" : -1, 
			"infoMessage" : "", 
			"configVersion" : 2 
		}, 
		{ 
			"_id" : 1, 
			"name" : "192.168.56.201:37018", 
			"ip" : "192.168.56.201", 
			"health" : 1, 
			"state" : 2, 
			"stateStr" : "SECONDARY", 
			"uptime" : 452, 
			"optime" : { 
				"ts" : Timestamp(1593868399, 1), 
				"t" : NumberLong(3) 
			}, 
			"optimeDurable" : { 
				"ts" : Timestamp(1593868399, 1), 
				"t" : NumberLong(3) 
			}, 
			"optimeDate" : ISODate("2020-07-04T13:13:19Z"), 
			"optimeDurableDate" : ISODate("2020-07-04T13:13:19Z"), 
			"lastHeartbeat" : ISODate("2020-07-04T13:13:27.622Z"), 
			"lastHeartbeatRecv" : ISODate("2020-07-04T13:13:27.493Z"), 
			"pingMs" : NumberLong(13), 
			"lastHeartbeatMessage" : "", 
			"syncingTo" : "", 
			"syncSourceHost" : "", 
			"syncSourceId" : -1, 
			"infoMessage" : "", 
			"configVersion" : 2 
		}, 
		{ 
			"_id" : 2, 
			"name" : "192.168.56.201:37019", 
			"ip" : "192.168.56.201", 
			"health" : 1, 
			"state" : 1, 
			"stateStr" : "PRIMARY", 
			"uptime" : 454, 
			"optime" : { 
				"ts" : Timestamp(1593868399, 1), 
				"t" : NumberLong(3) 
			}, 
			"optimeDate" : ISODate("2020-07-04T13:13:19Z"), 
			"syncingTo" : "", 
			"syncSourceHost" : "", 
			"syncSourceId" : -1, 
			"infoMessage" : "", 
			"electionTime" : Timestamp(1593867966, 1), 
			"electionDate" : ISODate("2020-07-04T13:06:06Z"), 
			"configVersion" : 2, 
			"self" : true, 
			"lastHeartbeatMessage" : "" 
		}, 
		{ 
			"_id" : 3, 
			"name" : "192.168.56.201:37020", 
			"ip" : "192.168.56.201", 
			"health" : 1, 
			"state" : 2, 
			"stateStr" : "SECONDARY", 
			"uptime" : 8, 
			"optime" : { 
				"ts" : Timestamp(1593868399, 1), 
				"t" : NumberLong(3) 
			}, 
			"optimeDurable" : { 
				"ts" : Timestamp(1593868399, 1), 
				"t" : NumberLong(3) 
			}, 
			"optimeDate" : ISODate("2020-07-04T13:13:19Z"), 
			"optimeDurableDate" : ISODate("2020-07-04T13:13:19Z"), 
			"lastHeartbeat" : ISODate("2020-07-04T13:13:27.418Z"), 
			"lastHeartbeatRecv" : ISODate("2020-07-04T13:13:27.823Z"), 
			"pingMs" : NumberLong(0), 
			"lastHeartbeatMessage" : "", 
			"syncingTo" : "", 
			"syncSourceHost" : "", 
			"syncSourceId" : -1, 
			"infoMessage" : "", 
			"configVersion" : 2 
		} 
	], 
	"ok" : 1, 
	"$clusterTime" : { 
		"clusterTime" : Timestamp(1593868399, 1), 
		"signature" : { 
			"hash" : BinData(0,"BZJ2tCwFE1NvE22/LwGzFTWy+1M="), 
			"keyId" : NumberLong("6845609731550085123") 
		} 
	}, 
	"operationTime" : Timestamp(1593868399, 1) 
} 

可以看到最新的节点已经加进去了

将节点初始化也放到yml中

如果熟练了,我们可以将副本集的初始化也放到yml中完成

version: '3.3' 
 
services: 
  mongodb1: 
    image: mongo:4.2.1 
    volumes: 
      - /data/mongo/data/mongo1:/data/db 
      - ./mongodb.key:/data/mongodb.key 
    user: root 
    environment: 
      - MONGO_INITDB_ROOT_USERNAME=handle 
      - MONGO_INITDB_ROOT_PASSWORD=jimeng2017 
      - MONGO_INITDB_DATABASE=handle 
    container_name: mongodb1 
    ports: 
      - 37017:27017 
    command: mongod --replSet mongos --keyFile /data/mongodb.key 
    restart: always 
    entrypoint: 
      - bash 
      - -c 
      - | 
        chmod 400 /data/mongodb.key 
        chown 999:999 /data/mongodb.key 
        exec docker-entrypoint.sh $$@ 
 
  mongodb2: 
    image: mongo:4.2.1 
    volumes: 
      - /data/mongo/data/mongo2:/data/db 
      - ./mongodb.key:/data/mongodb.key 
    user: root 
    environment: 
      - MONGO_INITDB_ROOT_USERNAME=handle 
      - MONGO_INITDB_ROOT_PASSWORD=jimeng2017 
      - MONGO_INITDB_DATABASE=handle 
    container_name: mongodb2 
    ports: 
      - 37018:27017 
    command: mongod --replSet mongos --keyFile /data/mongodb.key 
    restart: always 
    entrypoint: 
      - bash 
      - -c 
      - | 
        chmod 400 /data/mongodb.key 
        chown 999:999 /data/mongodb.key 
        exec docker-entrypoint.sh $$@ 
 
  mongodb3: 
    image: mongo:4.2.1 
    volumes: 
      - /data/mongo/data/mongo3:/data/db 
      - ./mongodb.key:/data/mongodb.key 
    user: root 
    environment: 
      - MONGO_INITDB_ROOT_USERNAME=handle 
      - MONGO_INITDB_ROOT_PASSWORD=jimeng2017 
      - MONGO_INITDB_DATABASE=handle 
    container_name: mongodb3 
    ports: 
      - 37019:27017 
    command: mongod --replSet mongos --keyFile /data/mongodb.key 
    restart: always 
    entrypoint: 
      - bash 
      - -c 
      - | 
        chmod 400 /data/mongodb.key 
        chown 999:999 /data/mongodb.key 
        exec docker-entrypoint.sh $$@ 
 
  mongodb4: 
    image: mongo:4.2.1 
    volumes: 
      - /data/mongo/data/mongo4:/data/db 
      - ./mongodb.key:/data/mongodb.key 
    user: root 
    environment: 
      - MONGO_INITDB_ROOT_USERNAME=handle 
      - MONGO_INITDB_ROOT_PASSWORD=jimeng2017 
      - MONGO_INITDB_DATABASE=handle 
    container_name: mongodb4 
    ports: 
      - 37020:27017 
    command: mongod --replSet mongos --keyFile /data/mongodb.key 
    restart: always 
    entrypoint: 
      - bash 
      - -c 
      - | 
        chmod 400 /data/mongodb.key 
        chown 999:999 /data/mongodb.key 
        exec docker-entrypoint.sh $$@ 
 
  mongodb-init: 
    image: mongo:4.2.1 
    depends_on: 
      - mongodb1 
      - mongodb2 
      - mongodb3 
      - mongodb4 
    restart: on-failure:5 
    command: 
      - mongo 
      - mongodb://handle:jimeng2017@192.168.56.201:37017/admin 
      - --eval 
      - 'rs.initiate({ _id: "mongos", members: [{_id:1,host:"192.168.56.201:37017"},{_id:2,host:"192.168.56.201:37018"},{_id:3,host:"192.168.56.201:37019"},{_id:4,host:"192.168.56.201:37020"}]})' 

这样通过docker-compose up -d就能完成镜像的构建和副本集的初始化

了解下Replica set

Replica set,由一组Mongod实例(进程)组成,包含一个Primary节点和多个Secondary节点,Mongodb Driver(客户端)的所有数据都写入Primary,Secondary从Primary同步写入的数据,通过这样的方式来保持复制集内所有成员存储相同的数据集,提供数据的高可用。

优点:

  • 确保数据安全
  • 高(24 * 7)数据可用性
  • 灾难恢复
  • 无需停机维护(例如备份,索引重建,压缩)
  • 读取缩放(要读取的额外副本)
  • 副本集对应用程序是透明的

复制在MongoDB中的工作方式

  • MongoDB通过使用副本集来实现复制。 副本集是一组托管相同数据集的mongod实例。 在副本中,一个节点是接收所有写操作的主节点。 所有其他实例,例如第二实例,都将应用来自第一实例的操作,以便它们具有相同的数据集。 副本集只能有一个主节点。
  • 副本集是一组两个或更多节点(通常至少需要3个节点)。
  • 在副本集中,一个节点是主要节点,其余节点是次要节点。
  • 所有数据从主节点复制到辅助节点。
  • 在自动故障转移或维护时,将为主节点建立选举,并选举一个新的主节点。
  • 恢复失败的节点后,它再次加入副本集并用作辅助节点。

下面就是工作的流程图

测试连接

使用go测试下是否能正常连接和读写数据。

show dbs;:查看数据库

> show dbs 
admin         0.000GB 
bs-cx         0.000GB 
config        0.000GB 
handle        0.001GB 
handle-core4  0.019GB 
local         0.020GB 
stud          0.000GB 

use stud;:切换到指定数据库,如果不存在该数据库就创建。

> use stud 
switched to db stud 

db;:显示当前所在数据库。

> db 
stud 

db.dropDatabase():删除当前数据库

> db.dropDatabase(); 
{ "ok" : 1 } 

测试写入数据,使用的包https://github.com/mongodb/mongo-go-driver

package main 
 
import ( 
	"context" 
	"fmt" 
	"go.mongodb.org/mongo-driver/bson" 
	"go.mongodb.org/mongo-driver/mongo" 
	"go.mongodb.org/mongo-driver/mongo/options" 
	"log" 
) 
 
type Student struct { 
	Name string 
	Age  int 
} 
 
func main() { 
	uri := "mongodb://handle:jimeng2017@192.168.56.201:37017,192.168.56.201:37018,192.168.56.201:37019,192.168.56.201:37020/admin?replicaSet=mongos" 
	// 设置客户端连接配置 
	clientOptions := options.Client().ApplyURI(uri) 
 
	// 连接到MongoDB 
	client, err := mongo.Connect(context.TODO(), clientOptions) 
	if err != nil { 
		log.Fatal(err) 
	} 
 
	// 检查连接 
	err = client.Ping(context.TODO(), nil) 
	if err != nil { 
		log.Fatal(err) 
	} 
	fmt.Println("Connected to MongoDB!") 
	collection := client.Database("stud").Collection("student") 
 
	s1 := Student{"小红", 12} 
	insertResult, err := collection.InsertOne(context.TODO(), s1) 
	if err != nil { 
		log.Fatal(err) 
	} 
	fmt.Println("Inserted a single document: ", insertResult.InsertedID) 
 
	var result Student 
	filter := bson.D{{"name", "小红"}} 
 
	err = collection.FindOne(context.TODO(), filter).Decode(&result) 
	if err != nil { 
		log.Fatal(err) 
	} 
	fmt.Printf("Found a single document: %+v\n", result) 
 
	// 断开连接 
	err = client.Disconnect(context.TODO()) 
	if err != nil { 
		log.Fatal(err) 
	} 
	fmt.Println("Connection to MongoDB closed.") 
} 

打印下输出

Connected to MongoDB! 
Inserted a single document:  ObjectID("5f00b6092aef651857151754") 
Found a single document: {Name:小红 Age:12} 
Connection to MongoDB closed. 

成功连接上了


本文参考链接:https://www.cnblogs.com/ricklz/p/13237419.html