Pymongo won't connect to Mongo replica set

Question

I can't seem to connect pymongo to a replica set I've created. The message I'm getting doesn't seem to make much sense as it's not what I'm seeing.

I'll first explain my configuration.

Basically I have three machines 10.141.0.156, 10.141.0.158, 10.141.0.159

I have 3 mongod instances, each running on a different machine, each running with:

mongod --configsvr --dbpath /mnt/sdb/ --port 27019

Next I've added the 3 mongod machines to a replica set:

{
    "set" : "replSet",
    "date" : ISODate("2016-04-01T12:23:12.552Z"),
    "myState" : 2,
    "term" : NumberLong(2),
    "syncingTo" : "10.141.0.158:27017",
    "configsvr" : true,
    "heartbeatIntervalMillis" : NumberLong(2000),
    "members" : [
        {
            "_id" : 0,
            "name" : "10.141.0.156:27017",
            "health" : 1,
            "state" : 2,
            "stateStr" : "SECONDARY",
            "uptime" : 2751,
            "optime" : {
                "ts" : Timestamp(1459513383, 6),
                "t" : NumberLong(2)
            },
            "optimeDate" : ISODate("2016-04-01T12:23:03Z"),
            "syncingTo" : "10.141.0.158:27017",
            "configVersion" : 2,
            "self" : true
        },
        {
            "_id" : 1,
            "name" : "10.141.0.158:27017",
            "health" : 1,
            "state" : 1,
            "stateStr" : "PRIMARY",
            "uptime" : 2749,
            "optime" : {
                "ts" : Timestamp(1459513383, 6),
                "t" : NumberLong(2)
            },
            "optimeDate" : ISODate("2016-04-01T12:23:03Z"),
            "lastHeartbeat" : ISODate("2016-04-01T12:23:11.054Z"),
            "lastHeartbeatRecv" : ISODate("2016-04-01T12:23:11.579Z"),
            "pingMs" : NumberLong(0),
            "electionTime" : Timestamp(1459510633, 1),
            "electionDate" : ISODate("2016-04-01T11:37:13Z"),
            "configVersion" : 2
        },
        {
            "_id" : 2,
            "name" : "10.141.0.159:27017",
            "health" : 1,
            "state" : 2,
            "stateStr" : "SECONDARY",
            "uptime" : 2749,
            "optime" : {
                "ts" : Timestamp(1459513383, 6),
                "t" : NumberLong(2)
            },
            "optimeDate" : ISODate("2016-04-01T12:23:03Z"),
            "lastHeartbeat" : ISODate("2016-04-01T12:23:11.261Z"),
            "lastHeartbeatRecv" : ISODate("2016-04-01T12:23:12.240Z"),
            "pingMs" : NumberLong(0),
            "syncingTo" : "10.141.0.158:27017",
            "configVersion" : 2
        }
    ],
    "ok" : 1
}

Next I've started the mongos on the first machine 10.141.0.156:

mongos --configdb replSet/10.141.0.156:27017,10.141.0.158:27017,10.141.0.159:27017 --port 27077

At this point everything is running normally and I'm not getting any errors.

Then I try to connect to the replica set with pymongo 3.2.1:

MongoClient("10.141.0.156", 27077, replicaSet='replSet')

When I try either to read all the keys, or to write, I get:

*** ServerSelectionTimeoutError: No replica set members available for replica set name "replSet"

Despite seeing the replica set in the mongo shell.

Saleem Saleem · Accepted Answer · 2016-04-01T15:02:13

For replicaset you'll need to start mongod instances which will participate in replicaset; with --replSet flag.

mongod --dbpath /mnt/sdb/ --port 27019 --replSet "your_replicaset_name"

with --configsvr option, you are starting a config server for sharding, not replicaset. for more information, see https://docs.mongodb.org/manual/reference/program/mongod/#bin.mongod

See this tutorial about how to setup replicaset: https://docs.mongodb.org/manual/tutorial/deploy-replica-set/

Pymongo won't connect to Mongo replica set

1 Answers