Java metrics for Java apps in Azure Container Apps

Java Virtual Machine (JVM) metrics are critical for monitoring the health and performance of your Java applications. The data collected includes insights into memory usage, garbage collection, thread count of your JVM. Use the following metrics to help ensure the health and stability of your applications.

Collected metrics

Category	Title	Description	Metric ID	Unit
Java	jvm.memory.total.used	Total amount of memory used by heap or nonheap	JvmMemoryTotalUsed	bytes
Java	jvm.memory.total.committed	Total amount of memory guaranteed to be available for heap or nonheap	JvmMemoryTotalCommitted	bytes
Java	jvm.memory.total.limit	Total amount of maximum obtainable memory for heap or nonheap	JvmMemoryTotalLimit	bytes
Java	jvm.memory.used	Amount of memory used by each pool	JvmMemoryUsed	bytes
Java	jvm.memory.committed	Amount of memory guaranteed to be available for each pool	JvmMemoryCommitted	bytes
Java	jvm.memory.limit	Amount of maximum obtainable memory for each pool	JvmMemoryLimit	bytes
Java	jvm.buffer.memory.usage	Amount of memory used by buffers, such as direct memory	JvmBufferMemoryUsage	bytes
Java	jvm.buffer.memory.limit	Amount of total memory capacity of buffers	JvmBufferMemoryLimit	bytes
Java	jvm.buffer.count	Number of buffers in the memory pool	JvmBufferCount	n/a
Java	jvm.gc.count	Count of JVM garbage collection actions	JvmGcCount	n/a
Java	jvm.gc.duration	Duration of JVM garbage collection actions	JvmGcDuration	milliseconds
Java	jvm.thread.count	Number of executing platform threads	JvmThreadCount	n/a

Configuration

To make the collection of Java metrics available to your app, you have to create your container app with some specific settings.

In the Create window, if you select for Deployment source the Container image option, then you have access to stack-specific features.

Under the Development stack-specific features and for the Development stack, select Java.

Once you select the Java development stack, the Customize Java features for your app window appears. Next to the Java features label, select JVM core metrics.

There are two CLI options related to the app runtime and Java metrics:

Option	Description
--runtime	The runtime of the container app. Supported values are generic and java.
--enable-java-metrics	A boolean option that enables or disables Java metrics for the app. Only applicable for Java runtime.

Note

The --enable-java-metrics=<true|false> parameter implicitly sets --runtime=java. The --runtime=generic parameter resets all java runtime info.

Enable Java metrics

You can enable Java metrics either via the create or update commands.

create

az containerapp create \
  --name <CONTAINER_APP_NAME> \
  --resource-group <RESOURCE_GROUP> \
  --image <CONTAINER_IMAGE_LOCATION> \
  --enable-java-metrics=true

update

az containerapp update \ 
  --name <CONTAINER_APP_NAME> \
  --resource-group <RESOURCE_GROUP> \
  --enable-java-metrics=true

Disable Java metrics

You can disable Java metrics using the up command.

az containerapp up \ 
  --name <CONTAINER_APP_NAME> \
  --resource-group <RESOURCE_GROUP> \
  --enable-java-metrics=false

Note

The container app restarts when you update java metrics flag.

View Java Metrics

Use the following steps to view metrics visualizations for your container app.

1. Go to the Azure portal.

2. Go to your container app.

3. Under the Monitoring section, select Metrics.

   From there, you're presented with a chart that plots the metrics you're tracking in your application.

   

You can see Java metric names on Azure Monitor, but the data sets report as empty unless you use the --enable-java-metrics parameter to enable Java metrics.

Next steps

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