Migrate MongoDB ReplicaSet to single MongoDB Node

downgrade_Mongodb_replica_to_standalone.txt

mongoserver:PRIMARY> rs.status();
{
	"set" : "mongoserver",
	"date" : ISODate("2016-02-02T10:47:07.510Z"),
	"myState" : 1,
	"members" : [
		{
			"_id" : 3,
			"name" : "192.168.1.10:37017",
			"health" : 1,
			"state" : 2,
			"stateStr" : "SECONDARY",
			"uptime" : 1195281,
			"optime" : Timestamp(1454409817, 1),
			"optimeDate" : ISODate("2016-02-02T10:43:37Z"),
			"lastHeartbeat" : ISODate("2016-02-02T10:47:07.230Z"),
			"lastHeartbeatRecv" : ISODate("2016-02-02T10:47:07.194Z"),
			"pingMs" : 0,
			"syncingTo" : "192.168.1.10:27017",
			"configVersion" : 16
		},
		{
			"_id" : 4,
			"name" : "192.168.1.10:47017",
			"health" : 1,
			"state" : 7,
			"stateStr" : "ARBITER",
			"uptime" : 1195281,
			"lastHeartbeat" : ISODate("2016-02-02T10:47:06.225Z"),
			"lastHeartbeatRecv" : ISODate("2016-02-02T10:47:07.238Z"),
			"pingMs" : 0,
			"configVersion" : 16
		},
		{
			"_id" : 5,
			"name" : "192.168.1.10:27017",
			"health" : 1,
			"state" : 1,
			"stateStr" : "PRIMARY",
			"uptime" : 1195286,
			"optime" : Timestamp(1454409817, 1),
			"optimeDate" : ISODate("2016-02-02T10:43:37Z"),
			"electionTime" : Timestamp(1453214750, 1),
			"electionDate" : ISODate("2016-01-19T14:45:50Z"),
			"configVersion" : 16,
			"self" : true
		}
	],
	"ok" : 1
}

##Remove Secondary
mongoserver:PRIMARY> rs.remove("192.168.1.10:37017")
{ "ok" : 1 }
mongoserver:PRIMARY> rs.remove("192.168.1.10:47017")
{ "ok" : 1 }

mongoserver:PRIMARY> rs.status();
{
	"set" : "mongoserver",
	"date" : ISODate("2016-02-02T10:48:23.214Z"),
	"myState" : 1,
	"members" : [
		{
			"_id" : 5,
			"name" : "192.168.1.10:27017",
			"health" : 1,
			"state" : 1,
			"stateStr" : "PRIMARY",
			"uptime" : 1195362,
			"optime" : Timestamp(1454410079, 1),
			"optimeDate" : ISODate("2016-02-02T10:47:59Z"),
			"electionTime" : Timestamp(1453214750, 1),
			"electionDate" : ISODate("2016-01-19T14:45:50Z"),
			"configVersion" : 18,
			"self" : true
		}
	],
	"ok" : 1
}


stop all mongo service
/etc/init.d/mongod1 stop
/etc/init.d/mongod2 stop
/etc/init.d/mongod3 stop

comment replicaset info in /etc/mongod1.conf
#replication:
#   replSetName: mongoserver


restart single node
/etc/init.d/mongod_single start

connect to mongo

> use local
switched to db local
> db.dropDatabase();
{ "dropped" : "local", "ok" : 1 }


restart mongo
/etc/init.d/mongod_single stop
/etc/init.d/mongod_single start

##Delete old folder data