M103 - Basic Cluster Administration - Mongo University - Solutions

M103 - Basic Cluster Administration - Mongo University - Solutions
==================================================

C:\Users\prins\Documents\m103\m103-vagrant-env

============================================================================================================
Chapter 0: Introduction & Setup
================================
vagrant ssh
validate_box
6445a3f8b6f1cc5873cf1ac94194903444602708d4eb189d42b6e65ca594d80d

============================================================================================================
Chapter 1: The Mongod
======================
mongod --dbpath /data/db/ --port 27000 --bind_ip "127.0.0.1,192.168.103.100" --auth

mongo admin --host localhost:27000 --eval '
  db.createUser({
    user: "m103-admin",
    pwd: "m103-pass",
    roles: [
      {role: "root", db: "admin"}
    ]
  })
'

Chapter 1: The Mongod
Lab - Launching Mongod :
-------------------------
validate_lab_launch_mongod
5a21c6dd403b6546001e79c0
-----------------------------------------------------------------------------------------------------------
mkdir /data/logs
vi /data/mongod.conf

storage:
  dbPath: "/data/db"
systemLog:
  path: "/data/logs/mongod.log"
  destination: "file"
net:
  bindIp : "127.0.0.1,192.168.103.100"
  port: 27000
security:
  authorization: enabled
processManagement:
  fork : true

mongod -f /data/mongod.conf

Chapter 1: The Mongod
Lab - Configuration File
--------------------------
validate_lab_configuration_file
5a2f0e41ae3c4e2f7427ee8f
---------------------------------------------------------------------------------------------------------
sudo mkdir -p /var/mongodb/db/
mkdir -p /var/mongodb/db/
sudo kill -9 2400
mongod -f /data/mongod.conf
rm -rf mongodb-27000.sock
sudo chown -R vagrant:vagrant /var/mongodb/db/

storage:
  dbPath: "/var/mongodb/db/"
systemLog:
  path: "/data/logs/mongod.log"
  destination: "file"
net:
  bindIp : "127.0.0.1,192.168.103.100"
  port: 27000
security:
  authorization: enabled
processManagement:
  fork : true

mongo admin --host localhost:27000 --eval '
  db.createUser({
    user: "m103-admin",
    pwd: "m103-pass",
    roles: [
      {role: "root", db: "admin"}
    ]
  })
'

Chapter 1: The Mongod
Lab - Change the Default DB Path
---------------------------------
validate_lab_change_dbpath
5a2f973bcb6b357b57e6bf43
--------------------------------------------------------------
mongo admin --port 27000 -u m103-admin -p m103-pass --eval 'db.shutdownServer()'

storage:
  dbPath: "/var/mongodb/db/"
systemLog:
  path: "/var/mongodb/db/mongod.log"
  destination: "file"
  logAppend: true
net:
  bindIp : "127.0.0.1,192.168.103.100"
  port: 27000
security:
  authorization: enabled
processManagement:
  fork : true
operationProfiling:
  slowOpThresholdMs: 50

Chapter 1: The Mongod
Lab - Logging to a Different Facility
---------------------------------------
validate_lab_different_logpath
5a32e5835d7a25685155aa61
--------------------------------------------------------------
mongo admin --host localhost:27000 -u m103-admin -p m103-pass --eval '
  db.createUser({
    user: "m103-application-user",
    pwd: "m103-application-pass",
    roles: [
      {role: "readWrite", db: "applicationData"}
    ]
  })
'

Chapter 1: The Mongod
Lab - Creating First Application User
--------------------------------------
validate_lab_first_application_user
5a32fdd630bff1f2fcb87acf
-------------------------------------------------------------
mongoimport --port 27000 -u m103-application-user -p m103-application-pass --authenticationDatabase admin -d applicationData -c products /dataset/products.json

vagrant@m103:/tmp$ mongoimport --port 27000 -u m103-application-user -p m103-application-pass --authenticationDatabase admin -d applicationData -c products /dataset/products.json
2019-01-20T14:59:08.225+0000    connected to: localhost:27000
2019-01-20T14:59:11.212+0000    [###.....................] applicationData.products     14.6MB/87.9MB (16.6%)
2019-01-20T14:59:14.212+0000    [#######.................] applicationData.products     29.0MB/87.9MB (32.9%)
2019-01-20T14:59:17.209+0000    [###########.............] applicationData.products     43.3MB/87.9MB (49.2%)
2019-01-20T14:59:20.209+0000    [###############.........] applicationData.products     57.3MB/87.9MB (65.2%)
2019-01-20T14:59:23.209+0000    [###################.....] applicationData.products     71.7MB/87.9MB (81.5%)
2019-01-20T14:59:26.209+0000    [#######################.] applicationData.products     86.5MB/87.9MB (98.4%)
2019-01-20T14:59:26.470+0000    [########################] applicationData.products     87.9MB/87.9MB (100.0%)
2019-01-20T14:59:26.472+0000    imported 516784 documents

Chapter 1: The Mongod
Lab - Importing a Dataset
--------------------------
validate_lab_import_dataset
5a383323ba6dbcf3cbcaec97
============================================================================================================================================
Chapter 2: Replicaiton
=======================

mongo admin --port 27000 -u m103-admin -p m103-pass --eval 'db.shutdownServer()'

mongod-repl-1.conf
vi mongod-repl-1.conf

storage:
  dbPath: /var/mongodb/db/1
net:
  bindIp: 192.168.103.100,localhost
  port: 27001
security:
  authorization: enabled
  keyFile: /var/mongodb/pki/m103-keyfile
systemLog:
  destination: file
  path: /var/mongodb/db/mongod1.log
  logAppend: true
processManagement:
  fork: true
replication:
  replSetName: m103-repl

cp mongod-repl-1.conf mongod-repl-2.conf
cp mongod-repl-1.conf mongod-repl-3.conf
vi mongod-repl-2.conf
vi mongod-repl-3.conf
mkdir /var/mongodb/db/{1,2,3}

sudo mkdir -p /var/mongodb/pki
sudo chown vagrant:vagrant -R /var/mongodb
openssl rand -base64 741 > /var/mongodb/pki/m103-keyfile
chmod 600 /var/mongodb/pki/m103-keyfile

mongod -f mongod-repl-1.conf
mongod -f mongod-repl-2.conf
mongod -f mongod-repl-3.conf

mongo --port 27001
rs.initiate()
use admin
db.createUser({
  user: "m103-admin",
  pwd: "m103-pass",
  roles: [
    {role: "root", db: "admin"}
  ]
})

exit
mongo --host "m103-repl/192.168.103.100:27001" -u "m103-admin" -p "m103-pass" --authenticationDatabase "admin"
rs.status()
rs.add("m103:27002")
rs.add("m103:27003")

Chapter 2: Replication
Lab - Initiate a Replica Set Locally
-------------------------------------
validate_lab_initialize_local_replica_set
5a4d32f979235b109001c7bc

----------------------------------------------------------------------------------------------------------------
mongo --host "m103-repl/192.168.103.100:27001" -u "m103-admin" -p "m103-pass" --authenticationDatabase "admin"
rs.stepDown()
rs.status()
rs.remove("192.168.103.100:27001")
rs.status()
rs.add("m103:27001")
rs.status()

Chapter 2: Replication
Lab - Remove and Re-Add a Node
--------------------------------
validate_lab_remove_readd_node
5a4fff19c0324e9feb9f60b9

-----------------------------------------------------------------------------------------------------------------
mongod -f mongod-repl-1.conf
mongod -f mongod-repl-2.conf
mongod -f mongod-repl-3.conf

mongo --host "m103-repl/m103:27001" -u "m103-admin" -p "m103-pass" --authenticationDatabase "admin" (or)
mongo --port 27001 -u "m103-admin" -p "m103-pass" --authenticationDatabase "admin"
rs.status()
mongo admin --port 27003 -u "m103-admin" -p "m103-pass" --authenticationDatabase "admin" --eval 'db.shutdownServer()'
use testDatabase
db.new_data.insert({"m103": "very fun"}, { writeConcern: { w: 3, wtimeout: 1000 }})

MongoDB Enterprise m103-repl:PRIMARY> use testDatabase
switched to db testDatabase
MongoDB Enterprise m103-repl:PRIMARY> db.new_data.insert({"m103": "very fun"}, { writeConcern: { w: 3, wtimeout: 1000 }})
WriteResult({
        "nInserted" : 1,
        "writeConcernError" : {
                "code" : 64,
                "codeName" : "WriteConcernFailed",
                "errInfo" : {
                        "wtimeout" : true
                },
                "errmsg" : "waiting for replication timed out"
        }
})

Chapter 2: Replication
Lab - Writes with Failovers
----------------------------
Correct:
1)When a writeConcernError occurs, the document is still written to the healthy nodes.
2)The unhealthy node will have the inserted document when it is brought back online.
Wrong:
1)w: "majority" would also cause this write operation to return with an error.
2)The write operation will always return with an error, even if wtimeout is not specified.

---------------------------------------------------------------------------------------------------------------------------
mongod -f mongod-repl-1.conf
mongod -f mongod-repl-2.conf
mongod -f mongod-repl-3.conf

mongoimport --drop \
--host m103-repl/192.168.103.100:27002,192.168.103.100:27001,192.168.103.100:27003 \
-u "m103-admin" -p "m103-pass" --authenticationDatabase "admin" \
--db applicationData --collection products /dataset/products.json

vagrant@m103:~$ mongoimport --drop \
> --host m103-repl/192.168.103.100:27002,192.168.103.100:27001,192.168.103.100:27003 \
> -u "m103-admin" -p "m103-pass" --authenticationDatabase "admin" \
> --db applicationData --collection products /dataset/products.json
2019-01-22T06:25:25.459+0000    connected to: m103-repl/192.168.103.100:27002,192.168.103.100:27001,192.168.103.100:27003
2019-01-22T06:25:25.471+0000    dropping: applicationData.products
2019-01-22T06:25:28.440+0000    [#.......................] applicationData.products     4.38MB/87.9MB (5.0%)
2019-01-22T06:25:31.440+0000    [##......................] applicationData.products     8.67MB/87.9MB (9.9%)
2019-01-22T06:25:34.439+0000    [###.....................] applicationData.products     13.0MB/87.9MB (14.8%)
2019-01-22T06:25:37.439+0000    [####....................] applicationData.products     17.2MB/87.9MB (19.5%)
2019-01-22T06:25:40.439+0000    [#####...................] applicationData.products     21.4MB/87.9MB (24.3%)
2019-01-22T06:25:43.439+0000    [######..................] applicationData.products     25.6MB/87.9MB (29.1%)
2019-01-22T06:25:46.439+0000    [########................] applicationData.products     29.6MB/87.9MB (33.7%)
2019-01-22T06:25:49.440+0000    [#########...............] applicationData.products     33.7MB/87.9MB (38.4%)
2019-01-22T06:25:52.439+0000    [##########..............] applicationData.products     38.0MB/87.9MB (43.2%)
2019-01-22T06:25:55.439+0000    [###########.............] applicationData.products     42.0MB/87.9MB (47.7%)
2019-01-22T06:25:58.439+0000    [############............] applicationData.products     46.3MB/87.9MB (52.6%)
2019-01-22T06:26:01.439+0000    [#############...........] applicationData.products     50.1MB/87.9MB (56.9%)
2019-01-22T06:26:04.440+0000    [##############..........] applicationData.products     54.0MB/87.9MB (61.4%)
2019-01-22T06:26:07.440+0000    [###############.........] applicationData.products     58.1MB/87.9MB (66.0%)
2019-01-22T06:26:10.439+0000    [################........] applicationData.products     62.2MB/87.9MB (70.8%)
2019-01-22T06:26:13.441+0000    [##################......] applicationData.products     66.6MB/87.9MB (75.7%)
2019-01-22T06:26:16.439+0000    [###################.....] applicationData.products     70.8MB/87.9MB (80.6%)
2019-01-22T06:26:19.439+0000    [####################....] applicationData.products     74.9MB/87.9MB (85.2%)
2019-01-22T06:26:22.439+0000    [#####################...] applicationData.products     79.0MB/87.9MB (89.8%)
2019-01-22T06:26:25.439+0000    [######################..] applicationData.products     83.3MB/87.9MB (94.7%)
2019-01-22T06:26:28.230+0000    [########################] applicationData.products     87.9MB/87.9MB (100.0%)
2019-01-22T06:26:28.230+0000    imported 516784 documents
vagrant@m103:~$

use applicationData
db.products.count()
MongoDB Enterprise m103-repl:PRIMARY> use applicationData
switched to db applicationData
MongoDB Enterprise m103-repl:PRIMARY> db.products.count()
516784

Chapter 2: Replication
Lab - Read Concern and Read Preferences
-----------------------------------------
Correct:
1)secondaryPreferred
2)nearest
3)secondary
4)primaryPreferred
Wrong:
primary
=============================================================================================================================================
Chapter 3: Sharding
====================

1)Bring up the config server replica set (CSRS)

csrs_1.conf
vi csrs_1.conf

sharding:
  clusterRole: configsvr
replication:
  replSetName: m103-csrs
security:
  keyFile: /var/mongodb/pki/m103-keyfile
net:
  bindIp: localhost,192.168.103.100
  port: 26001
systemLog:
  destination: file
  path: /var/mongodb/db/csrs1/mongod.log
  logAppend: true
processManagement:
  fork: true
storage:
  dbPath: /var/mongodb/db/csrs1

cp csrs_1.conf csrs_2.conf
cp csrs_1.conf csrs_3.conf
vi csrs_2.conf
vi csrs_3.conf
mkdir /var/mongodb/db/{csrs1,csrs2,csrs3}

mongod -f csrs_1.conf
mongod -f csrs_2.conf
mongod -f csrs_3.conf

mongo --port 26001
rs.initiate()
use admin
db.createUser({
  user: "m103-admin",
  pwd: "m103-pass",
  roles: [
    {role: "root", db: "admin"}
  ]
})

db.auth("m103-admin","m103-pass")

exit
mongo --host "m103-csrs/192.168.103.100:26001" -u "m103-admin" -p "m103-pass" --authenticationDatabase "admin"
rs.status()
rs.add("m103:26002")
rs.add("m103:26003")

2. Bring up the mongos

mongos.conf
vi mongos.conf

sharding:
  configDB: m103-csrs/192.168.103.100:26001,192.168.103.100:26002,192.168.103.100:26003
security:
  keyFile: /var/mongodb/pki/m103-keyfile
net:
  bindIp: localhost,192.168.103.100
  port: 26000
systemLog:
  destination: file
  path: /var/mongodb/db/mongos.log
  logAppend: true
processManagement:
  fork: true

mongos -f mongos.conf

3. Reconfigure m103-repl

sharding:
  clusterRole: shardsvr
storage:
  wiredTiger:
     engineConfig:
        cacheSizeGB: .1


storage:
  dbPath: /var/mongodb/db/1
net:
  bindIp: 192.168.103.100,localhost
  port: 27001
security:
  authorization: enabled
  keyFile: /var/mongodb/pki/m103-keyfile
systemLog:
  destination: file
  path: /var/mongodb/db/mongod1.log
  logAppend: true
processManagement:
  fork: true
replication:
  replSetName: m103-repl
sharding:
  clusterRole: shardsvr
storage:
  wiredTiger:
     engineConfig:
        cacheSizeGB: .1

vi mongod-repl-1.conf
vi mongod-repl-2.conf
vi mongod-repl-3.conf

mongod -f mongod-repl-1.conf
mongod -f mongod-repl-2.conf
mongod -f mongod-repl-3.conf

4. Add m103-repl as the first shard

mongo --port 26000 -u "m103-admin" -p "m103-pass" --authenticationDatabase "admin"

sh.addShard("m103-repl/m103:27001")
-------------------------------------
Chapter 3: Sharding
Lab - Configure a Sharded Cluster
validate_lab_first_sharded_cluster
5a57de1cb1575291ce6e560a
---------------------------------------

mongod -f csrs_1.conf
mongod -f csrs_2.conf
mongod -f csrs_3.conf

mongod -f mongod-repl-1.conf
mongod -f mongod-repl-2.conf
mongod -f mongod-repl-3.conf

mongos -f mongos.conf

mongo admin --port 26000 -u "m103-admin" -p "m103-pass" --authenticationDatabase "admin" --eval 'db.shutdownServer()'

mongo admin --port 26001 -u "m103-admin" -p "m103-pass" --authenticationDatabase "admin" --eval 'db.shutdownServer()'
mongo admin --port 26002 -u "m103-admin" -p "m103-pass" --authenticationDatabase "admin" --eval 'db.shutdownServer()'
mongo admin --port 26003 -u "m103-admin" -p "m103-pass" --authenticationDatabase "admin" --eval 'db.shutdownServer()'

mongo admin --port 27001 -u "m103-admin" -p "m103-pass" --authenticationDatabase "admin" --eval 'db.shutdownServer()'
mongo admin --port 27002 -u "m103-admin" -p "m103-pass" --authenticationDatabase "admin" --eval 'db.shutdownServer()'
mongo admin --port 27003 -u "m103-admin" -p "m103-pass" --authenticationDatabase "admin" --eval 'db.shutdownServer()'

/var/mongodb/db/1
/var/mongodb/db/csrs1

--------------------------------------
--------------------------------------------------------------------------------------------------------------------------------
mkdir /var/mongodb/db/{4,5,6}

vi mongod-repl-4.conf

storage:
  dbPath: /var/mongodb/db/4
  wiredTiger:
     engineConfig:
        cacheSizeGB: .1
net:
  bindIp: 192.168.103.100,localhost
  port: 27004
security:
  keyFile: /var/mongodb/pki/m103-keyfile
systemLog:
  destination: file
  path: /var/mongodb/db/4/mongod.log
  logAppend: true
processManagement:
  fork: true
operationProfiling:
  slowOpThresholdMs: 50
replication:
  replSetName: m103-repl-2
sharding:
  clusterRole: shardsvr

cp mongod-repl-4.conf mongod-repl-5.conf
cp mongod-repl-4.conf mongod-repl-6.conf
vi mongod-repl-5.conf
vi mongod-repl-6.conf

mongod -f mongod-repl-4.conf
mongod -f mongod-repl-5.conf
mongod -f mongod-repl-6.conf

mongo --port 27004
rs.initiate()
use admin
db.createUser({
  user: "m103-admin",
  pwd: "m103-pass",
  roles: [
    {role: "root", db: "admin"}
  ]
})

db.auth("m103-admin","m103-pass")

exit
mongo --host "m103-repl/192.168.103.100:27001" -u "m103-admin" -p "m103-pass" --authenticationDatabase "admin"
rs.status()
rs.add("m103:27005")
rs.add("m103:27006")

sh.addShard("m103-repl-2/192.168.103.100:27004")

mongoimport --drop /dataset/products.json --port 26000 -u "m103-admin" \
-p "m103-pass" --authenticationDatabase "admin" \
--db m103 --collection products

sh.enableSharding("m103")
use m103
db.products.createIndex({"sku": 1})
sh.shardCollection("m103.products", {"sku" : 1 } ) or
db.adminCommand( { shardCollection: "m103.products", key: { sku: 1 } } )
------------------------------------
Chapter 3: Sharding
Lab - Shard a Collection
Choosing the Correct Shard Key
validate_lab_shard_collection
5a621149d083824c6d889865
------------------------------------
-----------------------------------------------------------------------------------------------------------------------------------

mongod -f csrs_1.conf
mongod -f csrs_2.conf
mongod -f csrs_3.conf

mongod -f mongod-repl-1.conf
mongod -f mongod-repl-2.conf
mongod -f mongod-repl-3.conf

mongod -f mongod-repl-4.conf
mongod -f mongod-repl-5.conf
mongod -f mongod-repl-6.conf

mongos -f mongos.conf

mongo admin --port 26000 -u "m103-admin" -p "m103-pass" --authenticationDatabase "admin"

use config
db.chunks.find().pretty()
----------------------------------------------------------
Chapter 3: Sharding
Lab - Documents in Chunks
validate_lab_document_chunks m103.products-sku_MinKey
5ac28a604c7baf1f5c25d51b
-----------------------------------------------------------
----------------------------------------------------------------------------------------------------------------------------------------

Chapter 3: Sharding
Lab - Detect Scatter Gather Queries
Correct Answers:
1)Query 1 performs a document fetch.
2)Query 1 performs an index scan before the sharding filter.
3)Query 2 performs a collection scan.
Incorrect Answers:
1)Query 2 uses the shard key.
2)Both queries perform a sharding filter before the document fetch.

======================================================================================================================================================
Final Exam
===========
Final: Question 1
------------------
Problem: Which of the following are valid command line instructions to start a mongod? You may assume that all specified files already exist.

Correct:
1)mongod --logpath /var/log/mongo/mongod.log --dbpath /data/db --fork
2)mongod -f /etc/mongod.conf
Incorrect:
1)mongod --dbpath /data/db --fork
2)mongod --log /var/log/mongo/mongod.log --authentication

----------------------------------------------------------

Final: Question 2
------------------

Problem: Given the following config file: How many directories must MongoDB have access to? Disregard the path to the configuration file itself.

storage:
  dbPath: /data/db
systemLog:
  destination: file
  path: /var/log/mongod.log
net:
  bindIp: localhost,192.168.0.100
security:
  keyFile: /var/pki/keyfile
processManagement:
  fork: true

Correct:
1)3
Incoeect:
1)1
2)2
3)4

------------------------------------------------------------

Final: Question 3
------------------

Problem: Given the following output from rs.status().members:

[
  {
    "_id": 0,
    "name": "localhost:27017",
    "health": 1,
    "state": 1,
    "stateStr": "PRIMARY",
    "uptime": 548,
    "optime": {
      "ts": Timestamp(1521038871, 1),
      "t": NumberLong("1")
    },
    "optimeDate": ISODate("2018-03-14T14:47:51Z"),
    "electionTime": Timestamp(1521038358, 2),
    "electionDate": ISODate("2018-03-14T14:39:18Z"),
    "configVersion": 2,
    "self": true
  },
  {
    "_id": 1,
    "name": "localhost:27018",
    "health": 1,
    "state": 2,
    "stateStr": "SECONDARY",
    "uptime": 289,
    "optime": {
      "ts": Timestamp(1521038871, 1),
      "t": NumberLong("1")
    },
    "optimeDurable": {
      "ts": Timestamp(1521038871, 1),
      "t": NumberLong("1")
    },
    "optimeDate": ISODate("2018-03-14T14:47:51Z"),
    "optimeDurableDate": ISODate("2018-03-14T14:47:51Z"),
    "lastHeartbeat": ISODate("2018-03-14T14:47:56.558Z"),
    "lastHeartbeatRecv": ISODate("2018-03-14T14:47:56.517Z"),
    "pingMs": NumberLong("0"),
    "syncingTo": "localhost:27022",
    "configVersion": 2
  },
  {
    "_id": 2,
    "name": "localhost:27019",
    "health": 1,
    "state": 2,
    "stateStr": "SECONDARY",
    "uptime": 289,
    "optime": {
      "ts": Timestamp(1521038871, 1),
      "t": NumberLong("1")
    },
    "optimeDurable": {
      "ts": Timestamp(1521038871, 1),
      "t": NumberLong("1")
    },
    "optimeDate": ISODate("2018-03-14T14:47:51Z"),
    "optimeDurableDate": ISODate("2018-03-14T14:47:51Z"),
    "lastHeartbeat": ISODate("2018-03-14T14:47:56.558Z"),
    "lastHeartbeatRecv": ISODate("2018-03-14T14:47:56.654Z"),
    "pingMs": NumberLong("0"),
    "syncingTo": "localhost:27022",
    "configVersion": 2
  },
  {
    "_id": 3,
    "name": "localhost:27020",
    "health": 1,
    "state": 2,
    "stateStr": "SECONDARY",
    "uptime": 289,
    "optime": {
      "ts": Timestamp(1521038871, 1),
      "t": NumberLong("1")
    },
    "optimeDurable": {
      "ts": Timestamp(1521038871, 1),
      "t": NumberLong("1")
    },
    "optimeDate": ISODate("2018-03-14T14:47:51Z"),
    "optimeDurableDate": ISODate("2018-03-14T14:47:51Z"),
    "lastHeartbeat": ISODate("2018-03-14T14:47:56.558Z"),
    "lastHeartbeatRecv": ISODate("2018-03-14T14:47:56.726Z"),
    "pingMs": NumberLong("0"),
    "syncingTo": "localhost:27022",
    "configVersion": 2
  },
  {
    "_id": 4,
    "name": "localhost:27021",
    "health": 0,
    "state": 8,
    "stateStr": "(not reachable/healthy)",
    "uptime": 0,
    "optime": {
      "ts": Timestamp(0, 0),
      "t": NumberLong("-1")
    },
    "optimeDurable": {
      "ts": Timestamp(0, 0),
      "t": NumberLong("-1")
    },
    "optimeDate": ISODate("1970-01-01T00:00:00Z"),
    "optimeDurableDate": ISODate("1970-01-01T00:00:00Z"),
    "lastHeartbeat": ISODate("2018-03-14T14:47:56.656Z"),
    "lastHeartbeatRecv": ISODate("2018-03-14T14:47:12.668Z"),
    "pingMs": NumberLong("0"),
    "lastHeartbeatMessage": "Connection refused",
    "configVersion": -1
  },
  {
    "_id": 5,
    "name": "localhost:27022",
    "health": 1,
    "state": 2,
    "stateStr": "SECONDARY",
    "uptime": 289,
    "optime": {
      "ts": Timestamp(1521038871, 1),
      "t": NumberLong("1")
    },
    "optimeDurable": {
      "ts": Timestamp(1521038871, 1),
      "t": NumberLong("1")
    },
    "optimeDate": ISODate("2018-03-14T14:47:51Z"),
    "optimeDurableDate": ISODate("2018-03-14T14:47:51Z"),
    "lastHeartbeat": ISODate("2018-03-14T14:47:56.558Z"),
    "lastHeartbeatRecv": ISODate("2018-03-14T14:47:55.974Z"),
    "pingMs": NumberLong("0"),
    "syncingTo": "localhost:27017",
    "configVersion": 2
  },
  {
    "_id": 6,
    "name": "localhost:27023",
    "health": 1,
    "state": 2,
    "stateStr": "SECONDARY",
    "uptime": 289,
    "optime": {
      "ts": Timestamp(1521038871, 1),
      "t": NumberLong("1")
    },
    "optimeDurable": {
      "ts": Timestamp(1521038871, 1),
      "t": NumberLong("1")
    },
    "optimeDate": ISODate("2018-03-14T14:47:51Z"),
    "optimeDurableDate": ISODate("2018-03-14T14:47:51Z"),
    "lastHeartbeat": ISODate("2018-03-14T14:47:56.558Z"),
    "lastHeartbeatRecv": ISODate("2018-03-14T14:47:56.801Z"),
    "pingMs": NumberLong("0"),
    "syncingTo": "localhost:27022",
    "configVersion": 2
  }
]

At this moment, how many replica set members are eligible to become primary in the event of the current Primary crashing or stepping down?

Correct:
1)5
Incorrect:
1)4
2)6
3)7

------------------------------------------------------------
Final: Question 4
------------------

Problem: Given the following replica set configuration:

conf = {
  "_id": "replset",
  "version": 1,
  "protocolVersion": 1,
  "members": [
    {
      "_id": 0,
      "host": "192.168.103.100:27017",
      "priority": 2,
      "votes": 1
    },
    {
      "_id": 0,
      "host": "192.168.103.100:27018",
      "priority": 1,
      "votes": 1
    },
    {
      "_id": 2,
      "host": "192.168.103.100:27018",
      "priority": 1,
      "votes": 1
    }
  ]
}

What errors are present in the above replica set configuration?

Correct:
1)You cannot specify the same host information amoung multiple members.
2)You cannot specify two members with the same _id
Incorrect:
1)You can only specify a priority of 0 or 1, member "_id": 0 is incorrectly configured
2)you cannot have three members in a replica set.

-------------------------------------------------------------------------------------
Final: Question 5
------------------

Problem: Given the following replica set configuration:

conf = {
  "_id": "replset",
  "version": 1,
  "protocolVersion": 1,
  "members": [
    {
      "_id": 0,
      "host": "localhost:27017",
      "priority": 1,
      "votes": 1
    },
    {
      "_id": 1,
      "host": "localhost:27018",
      "priority": 1,
      "votes": 1
    },
    {
      "_id": 2,
      "host": "localhost:27019",
      "priority": 1,
      "votes": 1
    },
    {
      "_id": 3,
      "host": "localhost:27020",
      "priority": 0,
      "votes": 0,
      "slaveDelay": 3600
    }
  ]
}

What is the most likely role served by the node with "_id": 3?

Correct:
1)It serves as a "hot" backup of data in case of accidental data loss on the other members, like a DBA accidentally dropping the database.
Incorrect:
1)It servers to service reads and writes for people in the same geographic region as the host machine
2)It servers as a reference to perform analytics on how data is changing over time
3)It serves as a hidden secondary available to use for non-critical analysis operations

-------------------------------------------------------------------------------------------------------------
Final: Question 6
------------------
Given the following shard key: { "country": 1, "_id": 1 }

Which of the following queries will be routed (targeted)? Remember that queries may be routed to more than one shard.

Correct:
1)db.customers.find({"country": "Norway", "_id": 54})
2)db.customers.find({"_id": 914, "country": "Sweden"})
3)db.customers.find({"country": { $gte: "Portugal", $lte: "Spain" }})
Incorrect:
1)db.customers.find({"_id": 455})

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