In this lab we will have a closer look at broker, queue and topic metrics provided via CloudWatch metrics. We also create a CloudWatch alarm which triggers an e-mail as soon as there are messages in the ActiveMQ.DLQ queue. The ActiveMQ.DLQ queue is a special queue used by Amazon MQ to store messages that failed to be processed multiple times (so called "poison messages").

1. Go to the Cloud9 IDE tab in the browser

Run the following command in one of the terminal windows to send a few message to a queue where no receiver is listening to:

java -jar ./bin/amazon-mq-client.jar -url $url -mode sender -type queue -destination workshop.DLQTest -name Sender-1 -ttl 1000

Note the ttl option. This means the message has a life time of only 1 second. All messages which are not consumed before the ttl expires are moved to the ActiveMQ.DLQ queue by default.

You should see a log output like the following:

[ActiveMQ Task-1] INFO org.apache.activemq.transport.failover.FailoverTransport - Successfully connected to ssl://b-4e4bfd69-7b83-4a27-9faf-4684cfa80443-1.mq.eu-central-1.amazonaws.com:61617
14.04.2018 11:33:03.609 - Sender: sent '[queue://workshop.DLQTest] [Sender-1] Message number 1'
14.04.2018 11:33:04.645 - Sender: sent '[queue://workshop.DLQTest] [Sender-1] Message number 2'
14.04.2018 11:33:05.680 - Sender: sent '[queue://workshop.DLQTest] [Sender-1] Message number 3'
...

2. Working with Amazon CloudWatch Metrics

While we are waiting for the above producer to generate a meaningful amount of data points, let's explore the metrics available in CloudWatch for the AmazonMQ service.

Navigate to the Amazon CloudWatch console. Click on Metrics in the left navigation pane.

AmazonMQ publishes metrics for the broker, such as Cpu Utilization, HeapUsage, NetworkOut. If you have an HA configuration with a primary and a secondary broker, you will have independent metrics for each instance.
Click on the AmazonMQ namespace and on Broker Metrics afterwards.

If you have multiple brokers running or already started a broker in the past, enter the name of your current broker in the search field and click enter, to filter the metrics for the workshop broker (primary and secondary).

By selecting some of the metrics, e.g. CpuUtilization, you can plot the metric for a given time-frame.

Make sure you selected a relative time interval in Amazon CloudWatch, e.g. last 2 hours.

AmazonMQ also publishes metrics for the Topics such as MemoryUsage, EnqueueCount (messages published by producers), DispatchCount (message delivered to consumers).

Go back to the AmazonMQ namespace by clicking on AmazonMQ. Click on AmazonMQ > Topic Metrics by Broker to navigate to the topic metrics. In the filter put the name of the topic you want to monitor, for example topicA.

AmazonMQ also publishes metrics for the Queues. Go back to the AmazonMQ namespace by clicking on AmazonMQ. Click on AmazonMQ > Queue Metrics by Broker to navigate to the queue metrics. You can use the filter to narrow the list of queues that are listed to select the one of interest, for example queueA.

3. Monitoring of an active queue

By now the producer that we started at the beginning should have generated enough data. Stop the producer by holding CTRL + C or or CONTROL + C in each terminal window.
To inspect the metric, select the checkbox for the queue ActiveMQ.DLQ and the metric name QueueSize for the broker(s). Then click the tab Graphed metrics.

4. Working with Amazon CloudWatch Alarms

Click on the bell image for the first broker to create a new CloudWatch Alarm. Enter the following values:

• Name: Failed message delivery from broker workshop-1
• Description: Failed message delivery from broker workshop-1
• Whenever: <see screenshot>
• Treat missing data as: good

Continue with the configuration and the following values:

• Whenever this alarm: State is ALARM
• Send notification to: Click New List and then enter notifyMe as the value for 'Enter a topic name...'
• Email list: <your e-mail address>

Then click Create Alarm to create the alarm.

If you are asked to Confirm new email addresses, click on I will do it later and navigate to your e-mail client.

After you have confirmed your e-mail subscription, wait a few seconds and you should receive a mail, triggered by CloudWatch Alarm.

To learn more about metrics, please visit Amazon CloudWatch Monitoring.

Completion

Congratulations, you've successfully completed Lab 5! You can move on to Lab 6: Tighten up Security with Access Control

Return to the Workshop Landing page