ERROR Uncaught exception in REST call to /metrics (org.apache.kafka.connect.runtime.rest.errors.ConnectExceptionMapper:61)

I am running a kafka connector in distributed mode, and explicitly disabled the jmx metrics exposure, still the /metrics endpoint is getting hit in every 45,12 seconds interval and returning 404 Resource not found error. Here is the full stack trace from the logs, I am sure what is causing this error and how to resolve it, any help would be much appriciated.

 ERROR Uncaught exception in REST call to /metrics (org.apache.kafka.connect.runtime.rest.errors.ConnectExceptionMapper:61)
javax.ws.rs.NotFoundException: HTTP 404 Not Found
    at org.glassfish.jersey.server.ServerRuntime$1.run(ServerRuntime.java:252)
    at org.glassfish.jersey.internal.Errors$1.call(Errors.java:248)
    at org.glassfish.jersey.internal.Errors$1.call(Errors.java:244)
    at org.glassfish.jersey.internal.Errors.process(Errors.java:292)
    at org.glassfish.jersey.internal.Errors.process(Errors.java:274)
    at org.glassfish.jersey.internal.Errors.process(Errors.java:244)
    at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:265)
    at org.glassfish.jersey.server.ServerRuntime.process(ServerRuntime.java:234)
    at org.glassfish.jersey.server.ApplicationHandler.handle(ApplicationHandler.java:680)
    at org.glassfish.jersey.servlet.WebComponent.serviceImpl(WebComponent.java:394)
    at org.glassfish.jersey.servlet.WebComponent.service(WebComponent.java:346)
    at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:366)
    at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:319)
    at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:205)
    at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:799)
    at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:554)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:233)
    at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1624)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:233)
    at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1440)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:188)
    at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:505)
    at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1594)
    at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:186)
    at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1355)
    at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
    at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:234)
    at org.eclipse.jetty.server.handler.StatisticsHandler.handle(StatisticsHandler.java:181)
    at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127)
    at org.eclipse.jetty.server.Server.handle(Server.java:516)
    at org.eclipse.jetty.server.HttpChannel.lambda$handle$1(HttpChannel.java:487)
    at org.eclipse.jetty.server.HttpChannel.dispatch(HttpChannel.java:732)
    at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:479)
    at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:277)
    at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:311)
    at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:105)
    at org.eclipse.jetty.io.ChannelEndPoint$1.run(ChannelEndPoint.java:104)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:338)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:315)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:173)
    at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:131)
    at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:409)
    at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:883)
    at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:1034)
    at java.base/java.lang.Thread.run(Thread.java:829)

I did try setting the jmx monitoring to false, even then it's still trying to hit the end point

java -Xms256M -Xmx2G -server -XX:+UseG1GC -XX:MaxGCPauseMillis=20 -XX:InitiatingHeapOccupancyPercent=35 -XX:+ExplicitGCInvokesConcurrent -XX:MaxInlineLevel=15 -Djava.awt.headless=true -Dcom.sun.management.jmxremote=false -Dkafka.logs.dir=/home/kafka_2.13-3.2.3/bin/../logs -Dlog4j.configuration=file:/home/kafka_2.13-3.2.3/bin/../config/connect-log4j.properties -cp /home/kafka_2.13-3.2.3/bin/../libs/activation-1.1.1.jar

Solution

There is no /metrics endpoint, for the Connect server - https://kafka.apache.org/documentation/#connect_rest

You'll need to add some external process such as Prometheus JMX Exporter or Jolokia which will run on a different port and expose /metrics path

explicitly disabled the jmx metrics exposure

The -D flags are for the JVM, primarily, not controlling any HTTP API

still the /metrics endpoint is getting hit

Do you have something like Prometheus running and trying to scrape metrics every 45 seconds?