JVM

The JVM instrumentation module provides a variety of out-of-the-box JVM and process metrics. To use it, add the following dependency:

implementation 'io.prometheus:prometheus-metrics-instrumentation-jvm:1.0.0'

<dependency>
    <groupId>io.prometheus</groupId>
    <artifactId>prometheus-metrics-instrumentation-jvm</artifactId>
    <version>1.0.0</version>
</dependency>

Now, you can register the JVM metrics as follows:

JvmMetrics.builder().register();

The line above will initialize all JVM metrics and register them with the default registry. If you want to register the metrics with a custom PrometheusRegistry, you can pass the registry as parameter to the register() call.

The sections below describe the individual classes providing JVM metrics. If you don’t want to register all JVM metrics, you can register each of these classes individually rather than using JvmMetrics.

JVM buffer pool metrics are provided by the JvmBufferPoolMetrics class. The data is coming from the BufferPoolMXBean. Example metrics:

# HELP jvm_buffer_pool_capacity_bytes Bytes capacity of a given JVM buffer pool.
# TYPE jvm_buffer_pool_capacity_bytes gauge
jvm_buffer_pool_capacity_bytes{pool="direct"} 8192.0
jvm_buffer_pool_capacity_bytes{pool="mapped"} 0.0
# HELP jvm_buffer_pool_used_buffers Used buffers of a given JVM buffer pool.
# TYPE jvm_buffer_pool_used_buffers gauge
jvm_buffer_pool_used_buffers{pool="direct"} 1.0
jvm_buffer_pool_used_buffers{pool="mapped"} 0.0
# HELP jvm_buffer_pool_used_bytes Used bytes of a given JVM buffer pool.
# TYPE jvm_buffer_pool_used_bytes gauge
jvm_buffer_pool_used_bytes{pool="direct"} 8192.0
jvm_buffer_pool_used_bytes{pool="mapped"} 0.0

JVM class loading metrics are provided by the JvmClassLoadingMetrics class. The data is coming from the ClassLoadingMXBean. Example metrics:

# HELP jvm_classes_currently_loaded The number of classes that are currently loaded in the JVM
# TYPE jvm_classes_currently_loaded gauge
jvm_classes_currently_loaded 1109.0
# HELP jvm_classes_loaded_total The total number of classes that have been loaded since the JVM has started execution
# TYPE jvm_classes_loaded_total counter
jvm_classes_loaded_total 1109.0
# HELP jvm_classes_unloaded_total The total number of classes that have been unloaded since the JVM has started execution
# TYPE jvm_classes_unloaded_total counter
jvm_classes_unloaded_total 0.0

JVM compilation metrics are provided by the JvmCompilationMetrics class. The data is coming from the CompilationMXBean. Example metrics:

# HELP jvm_compilation_time_seconds_total The total time in seconds taken for HotSpot class compilation
# TYPE jvm_compilation_time_seconds_total counter
jvm_compilation_time_seconds_total 0.152

JVM garbage collector metrics are provided by the JvmGarbageCollectorMetric class. The data is coming from the GarbageCollectorMXBean. Example metrics:

# HELP jvm_gc_collection_seconds Time spent in a given JVM garbage collector in seconds.
# TYPE jvm_gc_collection_seconds summary
jvm_gc_collection_seconds_count{gc="PS MarkSweep"} 0
jvm_gc_collection_seconds_sum{gc="PS MarkSweep"} 0.0
jvm_gc_collection_seconds_count{gc="PS Scavenge"} 0
jvm_gc_collection_seconds_sum{gc="PS Scavenge"} 0.0

JVM memory metrics are provided by the JvmMemoryMetrics class. The data is coming from the MemoryMXBean and the MemoryPoolMXBean. Example metrics:

# HELP jvm_memory_committed_bytes Committed (bytes) of a given JVM memory area.
# TYPE jvm_memory_committed_bytes gauge
jvm_memory_committed_bytes{area="heap"} 4.98597888E8
jvm_memory_committed_bytes{area="nonheap"} 1.1993088E7
# HELP jvm_memory_init_bytes Initial bytes of a given JVM memory area.
# TYPE jvm_memory_init_bytes gauge
jvm_memory_init_bytes{area="heap"} 5.20093696E8
jvm_memory_init_bytes{area="nonheap"} 2555904.0
# HELP jvm_memory_max_bytes Max (bytes) of a given JVM memory area.
# TYPE jvm_memory_max_bytes gauge
jvm_memory_max_bytes{area="heap"} 7.38983936E9
jvm_memory_max_bytes{area="nonheap"} -1.0
# HELP jvm_memory_objects_pending_finalization The number of objects waiting in the finalizer queue.
# TYPE jvm_memory_objects_pending_finalization gauge
jvm_memory_objects_pending_finalization 0.0
# HELP jvm_memory_pool_collection_committed_bytes Committed after last collection bytes of a given JVM memory pool.
# TYPE jvm_memory_pool_collection_committed_bytes gauge
jvm_memory_pool_collection_committed_bytes{pool="PS Eden Space"} 1.30023424E8
jvm_memory_pool_collection_committed_bytes{pool="PS Old Gen"} 3.47078656E8
jvm_memory_pool_collection_committed_bytes{pool="PS Survivor Space"} 2.1495808E7
# HELP jvm_memory_pool_collection_init_bytes Initial after last collection bytes of a given JVM memory pool.
# TYPE jvm_memory_pool_collection_init_bytes gauge
jvm_memory_pool_collection_init_bytes{pool="PS Eden Space"} 1.30023424E8
jvm_memory_pool_collection_init_bytes{pool="PS Old Gen"} 3.47078656E8
jvm_memory_pool_collection_init_bytes{pool="PS Survivor Space"} 2.1495808E7
# HELP jvm_memory_pool_collection_max_bytes Max bytes after last collection of a given JVM memory pool.
# TYPE jvm_memory_pool_collection_max_bytes gauge
jvm_memory_pool_collection_max_bytes{pool="PS Eden Space"} 2.727870464E9
jvm_memory_pool_collection_max_bytes{pool="PS Old Gen"} 5.542248448E9
jvm_memory_pool_collection_max_bytes{pool="PS Survivor Space"} 2.1495808E7
# HELP jvm_memory_pool_collection_used_bytes Used bytes after last collection of a given JVM memory pool.
# TYPE jvm_memory_pool_collection_used_bytes gauge
jvm_memory_pool_collection_used_bytes{pool="PS Eden Space"} 0.0
jvm_memory_pool_collection_used_bytes{pool="PS Old Gen"} 1249696.0
jvm_memory_pool_collection_used_bytes{pool="PS Survivor Space"} 0.0
# HELP jvm_memory_pool_committed_bytes Committed bytes of a given JVM memory pool.
# TYPE jvm_memory_pool_committed_bytes gauge
jvm_memory_pool_committed_bytes{pool="Code Cache"} 4128768.0
jvm_memory_pool_committed_bytes{pool="Compressed Class Space"} 917504.0
jvm_memory_pool_committed_bytes{pool="Metaspace"} 6946816.0
jvm_memory_pool_committed_bytes{pool="PS Eden Space"} 1.30023424E8
jvm_memory_pool_committed_bytes{pool="PS Old Gen"} 3.47078656E8
jvm_memory_pool_committed_bytes{pool="PS Survivor Space"} 2.1495808E7
# HELP jvm_memory_pool_init_bytes Initial bytes of a given JVM memory pool.
# TYPE jvm_memory_pool_init_bytes gauge
jvm_memory_pool_init_bytes{pool="Code Cache"} 2555904.0
jvm_memory_pool_init_bytes{pool="Compressed Class Space"} 0.0
jvm_memory_pool_init_bytes{pool="Metaspace"} 0.0
jvm_memory_pool_init_bytes{pool="PS Eden Space"} 1.30023424E8
jvm_memory_pool_init_bytes{pool="PS Old Gen"} 3.47078656E8
jvm_memory_pool_init_bytes{pool="PS Survivor Space"} 2.1495808E7
# HELP jvm_memory_pool_max_bytes Max bytes of a given JVM memory pool.
# TYPE jvm_memory_pool_max_bytes gauge
jvm_memory_pool_max_bytes{pool="Code Cache"} 2.5165824E8
jvm_memory_pool_max_bytes{pool="Compressed Class Space"} 1.073741824E9
jvm_memory_pool_max_bytes{pool="Metaspace"} -1.0
jvm_memory_pool_max_bytes{pool="PS Eden Space"} 2.727870464E9
jvm_memory_pool_max_bytes{pool="PS Old Gen"} 5.542248448E9
jvm_memory_pool_max_bytes{pool="PS Survivor Space"} 2.1495808E7
# HELP jvm_memory_pool_used_bytes Used bytes of a given JVM memory pool.
# TYPE jvm_memory_pool_used_bytes gauge
jvm_memory_pool_used_bytes{pool="Code Cache"} 4065472.0
jvm_memory_pool_used_bytes{pool="Compressed Class Space"} 766680.0
jvm_memory_pool_used_bytes{pool="Metaspace"} 6659432.0
jvm_memory_pool_used_bytes{pool="PS Eden Space"} 7801536.0
jvm_memory_pool_used_bytes{pool="PS Old Gen"} 1249696.0
jvm_memory_pool_used_bytes{pool="PS Survivor Space"} 0.0
# HELP jvm_memory_used_bytes Used bytes of a given JVM memory area.
# TYPE jvm_memory_used_bytes gauge
jvm_memory_used_bytes{area="heap"} 9051232.0
jvm_memory_used_bytes{area="nonheap"} 1.1490688E7

JVM memory pool allocation metrics are provided by the JvmMemoryPoolAllocationMetrics class. The data is obtained by adding a NotificationListener to the GarbageCollectorMXBean. Example metrics:

# HELP jvm_memory_pool_allocated_bytes_total Total bytes allocated in a given JVM memory pool. Only updated after GC, not continuously.
# TYPE jvm_memory_pool_allocated_bytes_total counter
jvm_memory_pool_allocated_bytes_total{pool="Code Cache"} 4336448.0
jvm_memory_pool_allocated_bytes_total{pool="Compressed Class Space"} 875016.0
jvm_memory_pool_allocated_bytes_total{pool="Metaspace"} 7480456.0
jvm_memory_pool_allocated_bytes_total{pool="PS Eden Space"} 1.79232824E8
jvm_memory_pool_allocated_bytes_total{pool="PS Old Gen"} 1428888.0
jvm_memory_pool_allocated_bytes_total{pool="PS Survivor Space"} 4115280.0

The JVM runtime info metric is provided by the JvmRuntimeInfoMetric class. The data is obtained via system properties and will not change throughout the lifetime of the application. Example metric:

# TYPE jvm_runtime info
# HELP jvm_runtime JVM runtime info
jvm_runtime_info{runtime="OpenJDK Runtime Environment",vendor="Oracle Corporation",version="1.8.0_382-b05"} 1

JVM thread metrics are provided by the JvmThreadsMetrics class. The data is coming from the ThreadMXBean. Example metrics:

# HELP jvm_threads_current Current thread count of a JVM
# TYPE jvm_threads_current gauge
jvm_threads_current 10.0
# HELP jvm_threads_daemon Daemon thread count of a JVM
# TYPE jvm_threads_daemon gauge
jvm_threads_daemon 8.0
# HELP jvm_threads_deadlocked Cycles of JVM-threads that are in deadlock waiting to acquire object monitors or ownable synchronizers
# TYPE jvm_threads_deadlocked gauge
jvm_threads_deadlocked 0.0
# HELP jvm_threads_deadlocked_monitor Cycles of JVM-threads that are in deadlock waiting to acquire object monitors
# TYPE jvm_threads_deadlocked_monitor gauge
jvm_threads_deadlocked_monitor 0.0
# HELP jvm_threads_peak Peak thread count of a JVM
# TYPE jvm_threads_peak gauge
jvm_threads_peak 10.0
# HELP jvm_threads_started_total Started thread count of a JVM
# TYPE jvm_threads_started_total counter
jvm_threads_started_total 10.0
# HELP jvm_threads_state Current count of threads by state
# TYPE jvm_threads_state gauge
jvm_threads_state{state="BLOCKED"} 0.0
jvm_threads_state{state="NEW"} 0.0
jvm_threads_state{state="RUNNABLE"} 5.0
jvm_threads_state{state="TERMINATED"} 0.0
jvm_threads_state{state="TIMED_WAITING"} 2.0
jvm_threads_state{state="UNKNOWN"} 0.0
jvm_threads_state{state="WAITING"} 3.0

Process metrics are provided by the ProcessMetrics class. The data is coming from the OperatingSystemMXBean, the RuntimeMXBean, and from the /proc/self/status file on Linux. The metrics with prefix process_ are not specific to Java, but should be provided by every Prometheus client library, see Process Metrics in the Prometheus writing client libraries documentation. Example metrics:

# HELP process_cpu_seconds_total Total user and system CPU time spent in seconds.
# TYPE process_cpu_seconds_total counter
process_cpu_seconds_total 1.63
# HELP process_max_fds Maximum number of open file descriptors.
# TYPE process_max_fds gauge
process_max_fds 524288.0
# HELP process_open_fds Number of open file descriptors.
# TYPE process_open_fds gauge
process_open_fds 28.0
# HELP process_resident_memory_bytes Resident memory size in bytes.
# TYPE process_resident_memory_bytes gauge
process_resident_memory_bytes 7.8577664E7
# HELP process_start_time_seconds Start time of the process since unix epoch in seconds.
# TYPE process_start_time_seconds gauge
process_start_time_seconds 1.693829439767E9
# HELP process_virtual_memory_bytes Virtual memory size in bytes.
# TYPE process_virtual_memory_bytes gauge
process_virtual_memory_bytes 1.2683624448E10