Automatic failover behavior in MongoDB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check the current primary in a MongoDB replica set.

MongoDB

rs.isMaster().[1]

Drag options to blanks, or click blank then click option'

Asecondary

Bprimary

Carbiter

Dhosts

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing 'secondary' which is a read-only node.

Selecting 'hosts' which lists all nodes but not the primary.

The primary field in rs.isMaster() output shows the current primary node.

2fill in blank

medium

Complete the command to force a step down of the current primary in MongoDB.

MongoDB

rs.[1](60)

Drag options to blanks, or click blank then click option'

Areconfig

Bfreeze

CstepDown

Dstatus

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'reconfig' which changes replica set config but doesn't step down.

Using 'freeze' which prevents elections but doesn't step down.

The stepDown() command forces the primary to step down for the specified seconds.

3fill in blank

hard

Fix the error in the command to check replica set status.

MongoDB

rs.[1]()

Drag options to blanks, or click blank then click option'

Astatus

Bstat

Cstate

Dinfo

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'stat' which is not a valid command.

Using 'state' or 'info' which do not exist as rs commands.

The correct command to check replica set status is rs.status().

4fill in blank

hard

Fill both blanks to create a MongoDB query that reads from a secondary node with a max staleness of 90 seconds.

MongoDB

db.getMongo().setReadPref('[1]', [2])

Drag options to blanks, or click blank then click option'

Asecondary

B{ maxStalenessSeconds: 90 }

Cprimary

D{ maxStalenessSeconds: 30 }

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'primary' as read preference which reads only from primary.

Setting maxStalenessSeconds to 30 instead of 90.

To read from a secondary with a max staleness of 90 seconds, use read preference 'secondary' and set maxStalenessSeconds to 90.

5fill in blank

hard

Fill all three blanks to configure a replica set member as an arbiter with priority 0 and votes 1.

MongoDB

{ _id: 2, host: '[1]', arbiterOnly: [2], priority: [3] }

Drag options to blanks, or click blank then click option'

Aarbiter1.example.net:27017

Btrue

C0

Dfalse

Attempts:

3 left

💡 Hint

Common Mistakes

Setting arbiterOnly to false which makes it a normal member.

Giving priority other than 0 for an arbiter.

An arbiter member has arbiterOnly: true, priority: 0, and a host address.