MongoDB: can't shard on localhost because of shard socket exception

问题

I'm trying the MongoDB's shard tutorial, for some simple testing (proof-of-concept project).

I want to try sharding on a single machine. Is this possible and/or does it make any sense?

When I follow the guide steps, it does not work.

First, I start the mongod configsrv database instances on my machine:

bin/mongod --configsvr --dbpath $BASEDIR/data/configdb --port 27019 &
bin/mongod --configsvr --dbpath $BASEDIR/data/configdb1 --port 27020 &
bin/mongod --configsvr --dbpath $BASEDIR/data/configdb2 --port 27021 &

Then, I start the mongos instances so that they "bind" to the config servers:

HOST=$(uname -n) # my machine's name
# starts on default poort 27017
bin/mongos --configdb $HOST:27019,$HOST:27020,$HOST:27021

Until here, everything looks good.

Now I want to add a Shard to the cluster:

bin/mongo --host $(uname -n)

It enters the MongoDB shell.

connecting to: my.machine.name:27017/test

But when I try to add a new shard, I have the following error:

mongos> sh.addShard( "rs1/my.machine.name:27017" )
{
    "ok" : 0,
    "errmsg" : "couldn't connect to new shard socket exception [CONNECT_ERROR] for rs1/my.machine.name:27017"
}

I have tried with ip, machine's alias, localhost ... nothing seems to work.

Anyone could help me on this? Maybe I'm missing a point.

Thanks in advance

回答1:

I had the same problem, you have to run

mongod &

on your each of your shards

and then you can call

sh.addShard( "rs1/my.machine.name:27017" )

回答2:

Its possible, follow below sequence.

lets say we want to create a cluster with 3 shards each with 1 replica on same machine.

Start first mongod server (shard 1 with replica 1)with a replica set named s1
Start second mongod server (shard 2 with replica 1)with a replica set named s2
Start third mongod server (shard 3 with replica 1)with a replica set named s3

mkdir -p /data/shard0/rs0 /data/shard0/rs1 /data/shard0/rs2

/bin/mongod --replSet Sv1 --logpath "Sv1-r0.log" --dbpath /data/shard0/rs0 --port 37017

/bin/mongod --replSet Sv2 --logpath "Sv2-r0.log" --dbpath /data/shard0/rs1 --port 47017

/bin/mongod --replSet Sv3 --logpath "Sv3-r0.log" --dbpath /data/shard0/rs2 --port 57017

This will start 3 mongod servers/shards with one replica for each shard

/bin/mongo --port 37017 << 'EOF'
config = { _id: "Sv1", members:[
          { _id : 0, host : "<ip>:37017" }]};
rs.initiate(config)
EOF

This will add replicas to replica set Sv1. This should be done for each shard i.e. on each port 47017 and 57017

Now we have cluster ready with shards and replicas but no one knows other shards and replicas, thus we need config server

/bin/mongod --logpath "cfg-a.log" --dbpath /data/config/config-a --port 57040 --fork --configsvr

Then start mongos for admin access,

/bin/mongos --logpath "mongos-1.log" --configdb 10.88.66.218:57040

Now add shards to our cluster,

/bin/mongo <<'EOF'
db.adminCommand( { addShard : "Sv1/"+"<ip>:37017" } );
db.adminCommand( { addShard : "Sv2/"+"<ip>:47017" } );
db.adminCommand( { addShard : "Sv3/"+"<ip>:57017" } );
use db
db.createCollection("col1")
db.adminCommand({enableSharding:"db"})                                       db.adminCommand({shardCollection: "db.col1", key: {_id:"hashed"}});
EOF

And that's it.... Cluster should be up with 3 shards. You can check with sh.status() command on mongos.

来源：https://stackoverflow.com/questions/29768355/mongodb-cant-shard-on-localhost-because-of-shard-socket-exception

标签

mongodb

sharding