~~~~~~~~~~~~~~~~~~~~~
~~ CONGFIG servers ~~
~~~~~~~~~~~~~~~~~~~~~

-- IMPORTANT: note that the SECURITY are initially disabled

~~ example mongod.conf for CONFIG server
----------------------------------------------->
storage:
  dbPath: "/data/mongodb/"
  journal:
    enabled: true
  wiredTiger:
    engineConfig:
      cacheSizeGB: 1

net:
  port: 27017
  bindIp: 127.0.0.1,ivera-conf01,ivera-conf01-priv

#security:
  #authorization: 'enabled'
  #keyFile: /app/mongodb/conf/keyfile.basic

replication:
  replSetName: ivera_conf
  oplogSizeMB: 100
  enableMajorityReadConcern: true

sharding:
  clusterRole: configsvr
<-----------------------------------------------

-- replication setup
cfg = { 
	_id : "ivera_conf",
	members : [ { "_id" : 0, "host":"ivera-conf01-priv:27017"},],
	configsvr: true,
}
rs.initiate(cfg)

rs.add('ivera-conf02-priv:27017');

rs.conf();
rs.status();

-- security setup on PRIMARY
use admin
db.createUser({ user: "superhero",  pwd: "secret", roles: ["root"]});

-- uncomment SECURITY lines from config file on PRIMARY/SECONDARY and restart MongoDB instances

~~~~~~~~~~~~~~~~~~
~~ DATA servers ~~
~~~~~~~~~~~~~~~~~~

-- on DATA servers, the security can be implemented before or after replication setup

~~ example mongod.conf for DATA server
----------------------------------------------->
storage:
  dbPath: "/data/mongodb/"
  journal:
    enabled: true
  wiredTiger:
    engineConfig:
      cacheSizeGB: 1

net:
  port: 27017
  bindIp: 127.0.0.1,ivera-mongo01,ivera-mongo01-priv

security:
  authorization: 'enabled'
  keyFile: /app/mongodb/conf/keyfile.basic

replication:
  replSetName: ivera_data_01_02
  oplogSizeMB: 100
  enableMajorityReadConcern: true

sharding:
  clusterRole: shardsvr
<-----------------------------------------------

-- replication setup
cfg = { 
	_id : "ivera_conf",
	members : [ { "_id" : 0, "host":"ivera-conf01-priv:27017"},],
	configsvr: true,
}
rs.initiate(cfg)

rs.add('ivera-conf02-priv:27017');

rs.conf();
rs.status();


~~~~~~~~~~~~~~~~~~~~
~~ ROUTER servers ~~
~~~~~~~~~~~~~~~~~~~~

~~ example mongos.conf 
----------------------------------------------->
net:
  port: 27017
  bindIp: 127.0.0.1,ivera-router01,ivera-router01-priv

sharding:
  configDB: "ivera_conf/ivera-conf01:27017,ivera-conf01:27017"

security:
  keyFile: /app/mongodb/conf/keyfile.basic
<-----------------------------------------------

-- create SYSTEMD service for MongoDB Router
-- create service unit file /etc/systemd/system/mongos.service
----------------------------------------------->
[Unit]
Description=MongoDB Router
After=multi-user.target

[Service]
Type=simple
# (file size)
LimitFSIZE=infinity
# (cpu time)
LimitCPU=infinity
# (virtual memory size)
LimitAS=infinity
# (locked-in-memory size)
LimitMEMLOCK=infinity
# (open files)
LimitNOFILE=64000
# (processes/threads)
LimitNPROC=64000

User=mongod
Group=mongod

ExecStart=/app/mongodb/product/server/current_version/bin/mongos --config=/app/mongodb/conf/mongos.conf --logpath=/app/mongodb/log/mongos.log

[Install]
WantedBy=multi-user.target
<-----------------------------------------------

systemctl daemon-reload
systemctl start mongos
systemctl status mongos
systemctl enable mongos

-- connect to MongoDB Router un authentified mode and add shards
mongo --username "superhero" --password "******"

sh.addShard( "ivera_data_01_02/ivera-mongo01-priv:27017")
sh.addShard( "ivera_data_01_02/ivera-mongo02-priv:27017")
sh.addShard( "ivera_data_03_04/ivera-mongo03-priv:27017")
sh.addShard( "ivera_data_03_04/ivera-mongo04-priv:27017")
sh.addShard( "ivera_data_05_06/ivera-mongo05-priv:27017")
sh.addShard( "ivera_data_05_06/ivera-mongo06-priv:27017")

-- NOTE: a MongoDB router don't have any data locally -- except the mongos.conf file
-- We can create multiple MongoDB routers and use a load balancer to redirect user's calls

~~~~~~~~~~~~~~~~~~
~~ Test Cluster ~~
~~~~~~~~~~~~~~~~~~

-- create a database and activate sharding at the database level
use exampleDB
sh.enableSharding("exampleDB")

-- check database sharding
use config
db.databases.find()

-- create a collection and hash value of _id
db.exampleCollection.ensureIndex( { _id : "hashed" } )

-- shard the collection
sh.shardCollection( "exampleDB.exampleCollection", { "_id" : "hashed" } )

-- insert documents
for (var i = 1; i <= 500; i++) db.exampleCollection.insert( { x : i } )

-- display collection documents distributions across shards
db.exampleCollection.getShardDistribution()