Migration from MongoDB ReplicaSet setup to a Single Node Standalone setup: Example

all_commands

someuser$ mongo
  ## Check Status and member replica sets
  rs0:PRIMARY> rs.status()
  {
    "set" : "rs0",
    "date" : ISODate("2018-12-25T07:28:19.390Z"),
    "myState" : 1,
    "term" : NumberLong(136),
    "syncingTo" : "",
    "syncSourceHost" : "",
    "syncSourceId" : -1,
    "heartbeatIntervalMillis" : NumberLong(2000),
    "optimes" : {
      "lastCommittedOpTime" : {
        "ts" : Timestamp(1545722890, 1),
        "t" : NumberLong(136)
      },
      "readConcernMajorityOpTime" : {
        "ts" : Timestamp(1545722890, 1),
        "t" : NumberLong(136)
      },
      "appliedOpTime" : {
        "ts" : Timestamp(1545722890, 1),
        "t" : NumberLong(136)
      },
      "durableOpTime" : {
        "ts" : Timestamp(1545722890, 1),
        "t" : NumberLong(136)
      }
    },
    "lastStableCheckpointTimestamp" : Timestamp(1545722890, 1),
    "members" : [
      {
        "_id" : 0,
        "name" : "127.0.0.1:27017",
        "health" : 1,
        "state" : 1,
        "stateStr" : "PRIMARY",
        "uptime" : 7933,
        "optimeDate" : ISODate("2018-12-25T07:28:10Z"),
        "syncingTo" : "",
        "syncSourceHost" : "",
        "syncSourceId" : -1,
        "infoMessage" : "",
        "electionTime" : Timestamp(1545714968, 1),
        "electionDate" : ISODate("2018-12-25T05:16:08Z"),
        "configVersion" : 1,
        "self" : true,
        "lastHeartbeatMessage" : ""
      },
      {
        "_id" : 1,
        "name" : "127.0.0.1:47017",
        "health" : 1,
        "state" : 1,
        "stateStr" : "SECONDARY",
        "uptime" : 7933,
        "optime" : {
          "ts" : Timestamp(1545722890, 1),
          "t" : NumberLong(136)
        },
        "optimeDate" : ISODate("2018-12-25T07:28:10Z"),
        "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
      }
    ],
    "ok" : 1,
    "operationTime" : Timestamp(1545722890, 1),
    "$clusterTime" : {
      "clusterTime" : Timestamp(1545722890, 1),
      "signature" : {
        "hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
        "keyId" : NumberLong(0)
      }
    }
  }
  rs0:PRIMARY> rs.conf()
  {
    "_id" : "rs0",
    "version" : 1,
    "protocolVersion" : NumberLong(1),
    "writeConcernMajorityJournalDefault" : true,
    "members" : [
      {
        "_id" : 0,
        "host" : "127.0.0.1:27017",
        "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("5ba208c9112a69a520717a57")
    }
  }
  
  ## Remove Secondary Sets
  rs0:PRIMARY> rs.remove ("127.0.0.1:47017")
  {"ok": 1}

  rs0:PRIMARY> exit
  bye
#stop all mongo service  
someuser$ sudo service mongod stop
someuser$ sudo service mongod1 stop

# comment Replicaset info in /etc/mongod.conf
    #replication:
    # replSetName: rs0

#restart single node
sudo service mongod start

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

#restart mongo
sudo service mongod restart

## Delete old folder data