Key metrics to monitor in RabbitMQ - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check the number of messages ready in a RabbitMQ queue.

RabbitMQ

rabbitmqctl list_queues name messages_[1]

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

Aready

Bunacknowledged

Ctotal

Dconsumers

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'messages_unacknowledged' instead of 'messages_ready'.

The messages_ready metric shows how many messages are ready to be delivered to consumers.

2fill in blank

medium

Complete the command to monitor the number of consumers connected to a queue.

RabbitMQ

rabbitmqctl list_queues name [1]

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

Amessages_unacknowledged

Bconsumers

Cmessages_ready

Dmemory

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing 'consumers' with 'messages_ready'.

The consumers metric shows how many clients are currently consuming messages from the queue.

3fill in blank

hard

Fix the error in the command to list queues with unacknowledged messages.

RabbitMQ

rabbitmqctl list_queues name messages_[1]

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

Aready

Bpending

Cunacknowledged

Dwaiting

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'messages_pending' or 'messages_waiting' which are invalid.

The correct metric for messages delivered but not yet acknowledged is messages_unacknowledged.

4fill in blank

hard

Fill both blanks to list queues with their memory usage and number of consumers.

RabbitMQ

rabbitmqctl list_queues name [1] [2]

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

Amemory

Bconsumers

Cmessages_ready

Dmessages_unacknowledged

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing message counts with memory or consumers.

The memory metric shows how much memory the queue uses, and consumers shows how many clients consume from it.

5fill in blank

hard

Fill all three blanks to list queues with messages ready, unacknowledged, and consumers.

RabbitMQ

rabbitmqctl list_queues name [1] [2] [3]

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

Amemory

Bmessages_unacknowledged

Cconsumers

Dmessages_ready

Attempts:

3 left

💡 Hint

Common Mistakes

Incorrect order or using 'memory' instead of message counts.

This command shows the number of messages ready to deliver, messages sent but not acknowledged, and the number of consumers.

Practice

1. Which key metric helps you understand how many messages are waiting to be processed in RabbitMQ?

easy

A. Number of open connections

B. Queue length (number of messages ready or unacknowledged)

C. CPU usage of the RabbitMQ server

D. Disk space available on the server

Solution

1. Step 1: Understand message queue metrics

   The queue length shows how many messages are waiting or being processed, indicating workload.

2. Step 2: Identify the metric related to message backlog

   Queue length directly reflects message counts, unlike connections or CPU usage.

3. Final Answer:

   Queue length (number of messages ready or unacknowledged) -> Option B

4. Quick Check:

   Message backlog = Queue length [OK]

Hint: Messages waiting = queue length metric [OK]

Common Mistakes:

• Confusing connections count with message count
• Thinking CPU usage shows message backlog
• Ignoring unacknowledged messages in queue length

2. Which of the following rabbitmqctl commands correctly shows the number of connections to the RabbitMQ server?

easy

A. rabbitmqctl list_connections

B. rabbitmqctl show_connections

C. rabbitmqctl get_connections

D. rabbitmqctl connections_list

Solution

1. Step 1: Recall the correct command syntax

   The official command to list connections is rabbitmqctl list_connections.

2. Step 2: Verify other options are invalid

   Commands like show_connections, get_connections, and connections_list do not exist in rabbitmqctl.

3. Final Answer:

   rabbitmqctl list_connections -> Option A

4. Quick Check:

   List connections command = rabbitmqctl list_connections [OK]

Hint: Use 'list_connections' to see active connections [OK]

Common Mistakes:

• Using incorrect command verbs like show or get
• Mixing up command word order
• Assuming all commands start with 'get_'

3. Given the output of rabbitmqctl list_queues name messages_ready messages_unacknowledged as:

queue1 10 5
queue2 0 0
queue3 3 2

What is the total number of messages currently in all queues?

medium

A. 5

B. 15

C. 20

D. 10

Solution

1. Step 1: Sum messages_ready and messages_unacknowledged per queue

   queue1: 10 + 5 = 15, queue2: 0 + 0 = 0, queue3: 3 + 2 = 5

2. Step 2: Add totals from all queues

   15 + 0 + 5 = 20 total messages in all queues

3. Final Answer:

   20 -> Option C

4. Quick Check:

   Total messages = 20 [OK]

Hint: Add ready + unacknowledged messages for total [OK]

Common Mistakes:

• Counting only ready messages
• Ignoring unacknowledged messages
• Adding queue names instead of numbers

4. You run rabbitmqctl list_queues name messages_ready but get an error: unknown command. What is the most likely cause?

medium

A. The Management Plugin is not enabled

B. RabbitMQ server is not running

C. You do not have permission to run rabbitmqctl

D. The command syntax is incorrect or incomplete

Solution

1. Step 1: Check command syntax

   The command rabbitmqctl list_queues name messages_ready is valid, but if typed incorrectly or missing parts, it causes 'unknown command'.

2. Step 2: Rule out other causes

   Management Plugin absence does not cause this error; server down or permission issues give different errors.

3. Final Answer:

   The command syntax is incorrect or incomplete -> Option D

4. Quick Check:

   Syntax error = unknown command [OK]

Hint: Check command spelling and arguments carefully [OK]

Common Mistakes:

• Assuming plugin missing causes unknown command
• Ignoring typos in command
• Confusing permission errors with syntax errors

5. You want to monitor RabbitMQ queue health by alerting when the total messages (ready + unacknowledged) exceed 1000. Which approach is best to automate this monitoring?

hard

A. Use the Management Plugin's HTTP API to fetch queue metrics and trigger alerts

B. Manually run rabbitmqctl list_queues daily and check counts

C. Check server CPU usage as a proxy for queue length

D. Restart RabbitMQ server every hour to clear queues

Solution

1. Step 1: Identify automated monitoring methods

   The Management Plugin provides an HTTP API to programmatically get queue metrics for automation.

2. Step 2: Evaluate options for alerting

   Manual checks are slow and error-prone; CPU usage does not reflect queue length; restarting server is disruptive and not a solution.

3. Final Answer:

   Use the Management Plugin's HTTP API to fetch queue metrics and trigger alerts -> Option A

4. Quick Check:

   Automate with API = best practice [OK]

Hint: Automate with Management Plugin API for alerts [OK]

Common Mistakes:

• Relying on manual checks
• Using unrelated metrics like CPU usage
• Restarting server to fix queue issues