MongoDB开发环境Replica Set单机部署流程

Replica Set（复制集）是由一组MongoDB实例组成的集群，每个实例包含相同的数据集（除了arbiter节点）。通过Replica Set提供的数据冗余支持，提供高可用性、读写分离、自动故障转移等功能

如果是正式环境，当然应该部署在单独的服务器上。但是，开发环境需要测试/学习的话，一般会部署在一台服务器中

环境信息

数据库：MongoDB 4.0.9

操作系统：CentOS Linux release 7.3.1611

虚拟机：Oracle VirtualBox 6.0

部署流程

创建数据存放的文件夹：/data/mongodb/rs-0/1/2

cd /data
mkdir mongodb
cd mongodb/
mkdir rs0-0 rs0-1 rs0-2
chmod 777 -R /data/mongodb

　　

启动mongo实例

mongod --replSet rs0 --port 27017 --bind_ip localhost,jerry --dbpath /data/mongodb/rs0-0 --smallfiles --oplogSize 128
mongod --replSet rs0 --port 27018 --bind_ip localhost,jerry --dbpath /data/mongodb/rs0-1 --smallfiles --oplogSize 128
mongod --replSet rs0 --port 27019 --bind_ip localhost,jerry --dbpath /data/mongodb/rs0-2 --smallfiles --oplogSize 128

replSet：指定复制集名称，各个实例中需保持相同，这里设为rs0

port：端口监听的端口。默认为27017

bind_ip：绑定的计算机名

dbpath：数据目录路径。默认值为/data/db

也可以将配置信息保存到文件中，在mongo启动时通过-f参数指定配置文件

mongod -f /data/mongodb/rs1.conf

　　

感觉用默认端口27017不好，改到40001/40002/40003

新开一个连接，连接到mongo

mongo --port 40001

可以使用参数--host指定要连接的服务器名称，因为是localhost，所以不需要特别指定

在27017端口对应的shell上，可以看到如下信息

2019-05-31T09:43:02.640+0800 I NETWORK  [conn16] received client metadata from 127.0.0.1:38920 conn16: { application: { name: "MongoDB Shell" }, driver: { name: "MongoDB Internal Client", version: "4.0.9" }, os: { type: "Linux", name: "CentOS Linux release 7.3.1611 (Core) ", architecture: "x86_64", version: "Kernel 3.10.0-514.el7.x86_64" } }

　　

使用rs.status()查看复制集信息，可以看到40001是PRIMARY，其他两个是SECONDARY

syncingTo字段，可以看到40002从40001同步，40003从40002同步

rs0:PRIMARY> rs.status()
{
        "set" : "rs0",
        "date" : ISODate("2019-05-31T01:37:28.913Z"),
        "myState" : 1,
        "term" : NumberLong(12),
        "syncingTo" : "",
        "syncSourceHost" : "",
        "syncSourceId" : -1,
        "heartbeatIntervalMillis" : NumberLong(2000),
        "optimes" : {
                "lastCommittedOpTime" : {
                        "ts" : Timestamp(1559266646, 1),
                        "t" : NumberLong(12)
                },
                "readConcernMajorityOpTime" : {
                        "ts" : Timestamp(1559266646, 1),
                        "t" : NumberLong(12)
                },
                "appliedOpTime" : {
                        "ts" : Timestamp(1559266646, 1),
                        "t" : NumberLong(12)
                },
                "durableOpTime" : {
                        "ts" : Timestamp(1559266646, 1),
                        "t" : NumberLong(12)
                }
        },
        "lastStableCheckpointTimestamp" : Timestamp(1559266606, 1),
        "members" : [
                {
                        "_id" : 0,
                        "name" : "localhost:40001",
                        "health" : 1,
                        "state" : 1,
                        "stateStr" : "PRIMARY",
                        "uptime" : 158,
                        "optime" : {
                                "ts" : Timestamp(1559266646, 1),
                                "t" : NumberLong(12)
                        },
                        "optimeDate" : ISODate("2019-05-31T01:37:26Z"),
                        "syncingTo" : "",
                        "syncSourceHost" : "",
                        "syncSourceId" : -1,
                        "infoMessage" : "",
                        "electionTime" : Timestamp(1559266514, 1),
                        "electionDate" : ISODate("2019-05-31T01:35:14Z"),
                        "configVersion" : 1,
                        "self" : true,
                        "lastHeartbeatMessage" : ""
                },
                {
                        "_id" : 1,
                        "name" : "localhost:40002",
                        "health" : 1,
                        "state" : 2,
                        "stateStr" : "SECONDARY",
                        "uptime" : 143,
                        "optime" : {
                                "ts" : Timestamp(1559266646, 1),
                                "t" : NumberLong(12)
                        },
                        "optimeDurable" : {
                                "ts" : Timestamp(1559266646, 1),
                                "t" : NumberLong(12)
                        },
                        "optimeDate" : ISODate("2019-05-31T01:37:26Z"),
                        "optimeDurableDate" : ISODate("2019-05-31T01:37:26Z"),
                        "lastHeartbeat" : ISODate("2019-05-31T01:37:28.462Z"),
                        "lastHeartbeatRecv" : ISODate("2019-05-31T01:37:28.799Z"),
                        "pingMs" : NumberLong(0),
                        "lastHeartbeatMessage" : "",
                        "syncingTo" : "localhost:40001",
                        "syncSourceHost" : "localhost:40001",
                        "syncSourceId" : 0,
                        "infoMessage" : "",
                        "configVersion" : 1
                },
                {
                        "_id" : 2,
                        "name" : "localhost:40003",
                        "health" : 1,
                        "state" : 2,
                        "stateStr" : "SECONDARY",
                        "uptime" : 126,
                        "optime" : {
                                "ts" : Timestamp(1559266646, 1),
                                "t" : NumberLong(12)
                        },
                        "optimeDurable" : {
                                "ts" : Timestamp(1559266646, 1),
                                "t" : NumberLong(12)
                        },
                        "optimeDate" : ISODate("2019-05-31T01:37:26Z"),
                        "optimeDurableDate" : ISODate("2019-05-31T01:37:26Z"),
                        "lastHeartbeat" : ISODate("2019-05-31T01:37:28.460Z"),
                        "lastHeartbeatRecv" : ISODate("2019-05-31T01:37:27.989Z"),
                        "pingMs" : NumberLong(0),
                        "lastHeartbeatMessage" : "",
                        "syncingTo" : "localhost:40002",
                        "syncSourceHost" : "localhost:40002",
                        "syncSourceId" : 1,
                        "infoMessage" : "",
                        "configVersion" : 1
                }
        ],
        "ok" : 1,
        "operationTime" : Timestamp(1559266646, 1),
        "$clusterTime" : {
                "clusterTime" : Timestamp(1559266646, 1),
                "signature" : {
                        "hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
                        "keyId" : NumberLong(0)
                }
        }
}