Undertow

Undertow is a high-performance Java web server and web application framework. It is lightweight, flexible, and highly scalable, capable of efficiently handling high-concurrency requests. It supports multiple protocols (such as HTTP/1.1, HTTP/2, WebSocket, etc.) and is commonly used to build high-performance web applications and services.

Configuration¶

Enable DataKit Collectors¶

Enable the StatsD Collector

cp /usr/local/datakit/conf.d/statsd/statsd.conf.sample /usr/local/datakit/conf.d/statsd/statsd.conf

Enable the ddtrace Collector

cp /usr/local/datakit/conf.d/ddtrace/ddtrace.conf.sample /usr/local/datakit/conf.d/ddtrace/ddtrace.conf

Restart Datakit

datakit service -R

Application Configuration¶

Download dd-java-agent

SDK

Configure undertow.yaml

DDTrace retrieves Undertow metrics from JavaBeans

init_config:

instances:
  - jvm_direct: true
    name: undertow-monitoring
    collect_default_jvm_metrics: false
    collect_default_metrics: false
    refresh_beans: 60
    conf:
      - include:
          bean_regex: "org.xnio:type=Xnio,provider=\"nio\",worker=\"XNIO-.*\""
          attribute:
            IoThreadCount:
              metric_type: gauge
              alias: undertow.io.thread.count
      - include:
          bean_regex: "jboss.threads:name=\"XNIO-.*\",type=thread-pool"
          attribute:
            CorePoolSize:
              metric_type: gauge
              alias: undertow.core.pool.size
            MaximumPoolSize:
              metric_type: gauge
              alias: undertow.max.pool.size
            ActiveCount:
              metric_type: gauge
              alias: undertow.active.count
            LargestPoolSize:
              metric_type: gauge
              alias: undertow.largest.pool.size
            CompletedTaskCount:
              metric_type: gauge
              alias: undertow.completed.task.count
            PoolSize:
              metric_type: gauge
              alias: undertow.pool.size
            GrowthResistance:
              metric_type: gauge
              alias: undertow.growth.resistance
            MaximumQueueSize:
              metric_type: gauge
              alias: undertow.max.queue.size
            LargestQueueSize:
              metric_type: gauge
              alias: undertow.largest.queue.size
            SubmittedTaskCount:
              metric_type: gauge
              alias: undertow.submitted.task.count
            RejectedTaskCount:
              metric_type: gauge
              alias: undertow.rejected.task.count
            SpinMissCount:
              metric_type: gauge
              alias: undertow.spin.miss.count
            QueueSize:
              metric_type: gauge
              alias: undertow.queue.size
            KeepAliveTimeSeconds:
              metric_type: gauge
              alias: undertow.keep.alive.time.seconds

Startup Command

java \
-javaagent:/xxx/dd-java-agent.jar \
-Ddd.agent.port=9529 \
-Ddd.service=demo \
-Ddd.jmxfetch.check-period=1000 \
-Ddd.jmxfetch.enabled=true \
-Ddd.jmxfetch.config.dir=/xxx/ \
-Ddd.jmxfetch.con]fig=undertow.yaml \
-jar xxxx.jar

Metrics¶

Measurement undertow

Metric	Description	Use Case
active_count	Active Thread Count	The number of threads currently executing tasks in the thread pool.
completed_task_count	Completed Task Count	The total number of tasks completed since the thread pool started.
core_pool_size	Core Thread Pool Size	The number of threads that remain active in the thread pool, even if they are idle.
io_thread_count	I/O Thread Count	The number of threads used by the underlying XNIO framework of Undertow to handle network I/O events (e.g., accepting connections, reading/writing data).
keep_alive_time_seconds	Thread Keep-Alive Time	The time that excess idle threads can wait before being terminated when the number of threads exceeds the core pool size.
largest_pool_size	Largest Pool Size	The maximum number of threads reached since the thread pool started.
largest_queue_size	Largest Queue Size	The maximum number of tasks in the task queue since it started.
max_pool_size	Maximum Pool Size	The maximum number of threads allowed in the thread pool. This is a critical configuration parameter that limits concurrency.
max_queue_size	Maximum Queue Size	The maximum number of tasks that the task queue can hold.
pool_size	Current Pool Size	The total number of threads in the thread pool (including active and idle threads).
queue_size	Current Queue Size	The number of tasks currently waiting in the task queue to be executed. A continuous increase usually indicates insufficient processing capacity.
rejected_task_count	Rejected Task Count	The number of tasks that were rejected due to the thread pool being full (maximum threads reached and queue full) or rejection policy triggered.