Java metrics for Java apps in Azure Container Apps

  • Article

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, configure 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.

Screenshot of the Azure portal where you can select Java-specific features for your container app.

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.

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

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.

    Screenshot of Java metrics visualization.

You can see Java metric names on Azure Monitor, but the data sets show as empty unless the feature is enabled. Refer to the Configuration section for how to enable it.