Connecting to shards in MongoDB mongo shell - mongodb

Question

I'm following the tutorial in the MongoDB: The Definitive Guide, 2nd edition, for a databases course, and it appears not to work in version 3.6.2.
Basically I have two mongo shells opened using mongo --nodb.
Then, in the first, I run cluster = new ShardingTest({"shards": 3, "chunksize": 1}) (which works and produces a steady stream of output).
In the second shell, the book says to run db = (new Mongo("localhost:30999")).getDB("test") which fails. I was told by a colleague instead to run db = (new Mongo("localhost:20000")).getDB("test"), which worked.
Then, I inserted data which worked as well. However, when trying sh.status(), I got the message printShardingStatus: this db does not have sharding enabled. be sure you are connecting to a mongos from the shell and not to a mongod.
After searching online, I figured I'd run sh.enableSharding(db) which also gave me the following error:
2018-03-01T11:05:22.654-0500 E QUERY [thread1] Error: not connected to a mongos :
sh._checkMongos#src/mongo/shell/utils_sh.js:8:15
sh._adminCommand#src/mongo/shell/utils_sh.js:18:9
sh.enableSharding#src/mongo/shell/utils_sh.js:98:12
#(shell):1:1
I'm running on a Windows 10 machine, and have the correct environmental variables set up and the db folder created, so any help/pointers would be much appreciated!
EDIT 1:
This error persists even if db.collection.ensureIndex() is run first.

Answer 1

Try connecting to the shell on port 20006 by opening a new mongo --nodb, then do db = (new Mongo("localhost:20006")).getDB("test")
This should open the mongos for all the shards, so now the command sh.status() should work, as well as other commands like setting balancer state and starting balancer.

Answer 2

The commands bellow show how to run 3 shards instances and 3 config instances in your localhost. For each of these shards also are created 3 replica sets (mongod instances), may it can help you:
clean everything up
echo "killing mongod and mongos"
killall mongod
killall mongos
echo "removing data files"
rm -rf /data/config
rm -rf /data/shard*
start a replica set and tell it that it will be shard0
echo "starting servers for shard 0"
mkdir -p /data/shard0/rs0 /data/shard0/rs1 /data/shard0/rs2
mongod --replSet s0 --logpath "s0-r0.log" --dbpath /data/shard0/rs0 --port 37017 --fork --shardsvr
mongod --replSet s0 --logpath "s0-r1.log" --dbpath /data/shard0/rs1 --port 37018 --fork --shardsvr
mongod --replSet s0 --logpath "s0-r2.log" --dbpath /data/shard0/rs2 --port 37019 --fork --shardsvr
sleep 5
connect to one server and initiate the set
echo "Configuring s0 replica set"
mongo --port 37017 << 'EOF'
config = { _id: "s0", members:[
{ _id : 0, host : "localhost:37017" },
{ _id : 1, host : "localhost:37018" },
{ _id : 2, host : "localhost:37019" }]};
rs.initiate(config)
EOF
start a replicate set and tell it that it will be a shard1
echo "starting servers for shard 1"
mkdir -p /data/shard1/rs0 /data/shard1/rs1 /data/shard1/rs2
mongod --replSet s1 --logpath "s1-r0.log" --dbpath /data/shard1/rs0 -port 47017 --fork --shardsvr
mongod --replSet s1 --logpath "s1-r1.log" --dbpath /data/shard1/rs1 --port 47018 --fork --shardsvr
mongod --replSet s1 --logpath "s1-r2.log" --dbpath /data/shard1/rs2 --port 47019 --fork --shardsvr
sleep 5
echo "Configuring s1 replica set"
mongo --port 47017 << 'EOF'
config = { _id: "s1", members:[
{ _id : 0, host : "localhost:47017" },
{ _id : 1, host : "localhost:47018" },
{ _id : 2, host : "localhost:47019" }]};
rs.initiate(config)
EOF
start a replicate set and tell it that it will be a shard2
echo "starting servers for shard 2"
mkdir -p /data/shard2/rs0 /data/shard2/rs1 /data/shard2/rs2
mongod --replSet s2 --logpath "s2-r0.log" --dbpath /data/shard2/rs0 --port 57017 --fork --shardsvr
mongod --replSet s2 --logpath "s2-r1.log" --dbpath /data/shard2/rs1 --port 57018 --fork --shardsvr
mongod --replSet s2 --logpath "s2-r2.log" --dbpath /data/shard2/rs2 --port 57019 --fork --shardsvr
sleep 5
echo "Configuring s2 replica set"
mongo --port 57017 << 'EOF'
config = { _id: "s2", members:[
{ _id : 0, host : "localhost:57017" },
{ _id : 1, host : "localhost:57018" },
{ _id : 2, host : "localhost:57019" }]};
rs.initiate(config)
EOF
now start 3 config servers
echo "Starting config servers"
mkdir -p /data/config/config-a /data/config/config-b /data/config/config-c
mongod --replSet csReplSet --logpath "cfg-a.log" --dbpath /data/config/config-a --port 57040 --fork --configsvr
mongod --replSet csReplSet --logpath "cfg-b.log" --dbpath /data/config/config-b --port 57041 --fork --configsvr
mongod --replSet csReplSet --logpath "cfg-c.log" --dbpath /data/config/config-c --port 57042 --fork --configsvr
echo "Configuring configuration server replica set"
mongo --port 57040 << 'EOF'
config = { _id: "csReplSet", members:[
{ _id : 0, host : "localhost:57040" },
{ _id : 1, host : "localhost:57041" },
{ _id : 2, host : "localhost:57042" }]};
rs.initiate(config)
EOF
now start the mongos on a standard port
mongos --logpath "mongos-1.log" --configdb csReplSet/localhost:57040,localhost:57041,localhost:57042 --fork
echo "Waiting 60 seconds for the replica sets to fully come online"
sleep 60
echo "Connnecting to mongos and enabling sharding"
add shards and enable sharding on the test db
mongo <<'EOF'
use admin
db.runCommand( { addshard : "s0/localhost:37017" } );
db.runCommand( { addshard : "s1/localhost:47017" } );
db.runCommand( { addshard : "s2/localhost:57017" } );
db.runCommand( { enableSharding: "test" } );
db.runCommand( { shardCollection: "test.some_collection", key: { some_id:1 } } );
EOF