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  • 11:00
    pnerg commented #1067
  • 11:00
    pnerg closed #1067
  • 09:46
    ivantopo commented #1067
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  • Oct 26 11:40
    nvollmar opened #1066
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    ivantopo on master

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  • Oct 26 06:00
    ivantopo closed #1065
  • Oct 25 15:47
    ivantopo edited #1065
Anyone have pointers where to look for Scala Futures with the wrong units when using Kamon with Play and DataDog? We're seeing a ton of errors like this and durations of 3 months or so...
Failed to record value [8784530422484846] on [span.elapsed-time,{operation=aws-s3.putObject,span.kind=internal,parentOperation=/v4/apiendpoint,error=false,component=scala.future}] because the value is outside of the configured range. The recorded value was adjusted to the highest trackable value [3600000000000]. You might need to change your dynamic range configuration for this metric
Never mind, I think I found it
6 replies
Dima Golomozy
anyone have idea why when im using native-packager and adding Kanela in the javaAgents, it looks like all the properties in the conf file are ignored. for example, i've put
kanela.modules.akka.enabled = false
but i still see akka metrics
3 replies
does Kamon work for Spring WebFlux endpoints?
1 reply
and same question for Reactor Kafka
Is it on the roadmap/in flight?
1 reply
Ivan Topolnjak
@/all hey people! I wanted to give Discord a try and created a server here: https://discord.gg/5JuYsDJ7au :smile: I'm going to be hanging out for a few weeks and see how it turns out. You are welcome to join!
Krisztian Lachata
Hi. I have a question. I enabled kamon status page. I clearly see that there is a metric called jvm.memory.used. I use influx and datadog reporter (via agent). JVM Metric is available in influx, I can query in grafana but when I query it in datadog my service does not appear. Many other metrics work fine but I do not understand what is the case with this one. Can somebody help me how can figure out what is going on here? I try to migrate to datadog from influx/grafana. thank you
5 replies
Ben Fradet
Hello I'm upgrading from "kamon-play-2.6" % "1.1.3" to kamon 2, so I have a "kamon-bundle" % "2.2.2" dependency as well as a addSbtPlugin("io.kamon" % "sbt-kanela-runner-play-2.8" % "2.0.9") sbt plugin.
However when launching the app, I run into java.lang.NoSuchMethodError: kamon.Kamon$.withContext any ideas how I can fix this?
3 replies
Hi, I am new to Kamon, and I am trying to create nested scopes and/or spans - I need to timestmap and trace the executions of rather complicated requests, which are dispatched thorugh the chain of actors. In particular, I'd like to create nested scope befroe ending message to actor, and close scope after message is processed. Or, I would like to create nested scope when running spawining child operation (which can spawn nested scopes as well). I ma not very clear waht is the proper way to do that.
All exmaples in Kamon documentation imply that span finishes in the same block where it started, and there is very little information about Scope. My understanding, while I can get currentContext and currentSpan, there is no way to get current scope, so I'd have to sotre it in e.g dynamicVariable to close it when I need it.
Can you suggest waht is the proepr way to create nested spans and nested scopes and properly finish/close them - sometiems in different module that the one it started ?
Another question - if I need to obtain e.g request id for request which took longest time - how do I store this request id, via mark ? And how to see this mark in e.g. Datadog ?
6 replies
Linh Mai

hi there

kamon.context.codecs.string-keys {
  request-id = "X-Request-ID"

seems to be deprectaded in kamon 2. is there an aquivalient

4 replies
Hi, new to Kamon and I'm running into issue w/ reporting tracing to datadog, once in a while
2021-07-27 13:42:37 ERROR ModuleRegistry:218 - Reporter [DatadogSpanReporter] failed to process a spans tick. java.io.EOFException: \n not found: limit=0 content=… at okio.RealBufferedSource.readUtf8LineStrict(RealBufferedSource.kt:332) ~[okio-jvm-2.8.0.jar:?] at okhttp3.internal.http1.HeadersReader.readLine(HeadersReader.kt:29) ~[okhttp-4.9.0.jar:?] at okhttp3.internal.http1.Http1ExchangeCodec.readResponseHeaders(Http1ExchangeCodec.kt:178) ~[okhttp-4.9.0.jar:?] at okhttp3.internal.connection.Exchange.readResponseHeaders(Exchange.kt:106) ~[okhttp-4.9.0.jar:?] at okhttp3.internal.http.CallServerInterceptor.intercept(CallServerInterceptor.kt:79) ~[okhttp-4.9.0.jar:?] at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.kt:109) ~[okhttp-4.9.0.jar:?] at kamon.okhttp3.instrumentation.KamonTracingInterceptor.intercept(KamonTracingInterceptor.scala:27) ~[kamon-bundle_2.13-2.2.0.jar:2.2.0] at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.kt:109) ~[okhttp-4.9.0.jar:?] at okhttp3.internal.connection.ConnectInterceptor.intercept(ConnectInterceptor.kt:34) ~[okhttp-4.9.0.jar:?] at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.kt:109) ~[okhttp-4.9.0.jar:?] at okhttp3.internal.cache.CacheInterceptor.intercept(CacheInterceptor.kt:95) ~[okhttp-4.9.0.jar:?] at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.kt:109) ~[okhttp-4.9.0.jar:?] at okhttp3.internal.http.BridgeInterceptor.intercept(BridgeInterceptor.kt:83) ~[okhttp-4.9.0.jar:?] at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.kt:109) ~[okhttp-4.9.0.jar:?] at okhttp3.internal.http.RetryAndFollowUpInterceptor.intercept(RetryAndFollowUpInterceptor.kt:76) ~[okhttp-4.9.0.jar:?] at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.kt:109) ~[okhttp-4.9.0.jar:?] at okhttp3.internal.connection.RealCall.getResponseWithInterceptorChain$okhttp(RealCall.kt:201) ~[okhttp-4.9.0.jar:?] at okhttp3.internal.connection.RealCall.execute(RealCall.kt:154) ~[okhttp-4.9.0.jar:?] at kamon.datadog.package$HttpClient.$anonfun$doRequest$1(package.scala:57) ~[kamon-datadog_2.13-2.2.0.jar:2.2.0] at scala.util.Try$.apply(Try.scala:210) ~[scala-library-2.13.3.jar:?] at kamon.datadog.package$HttpClient.doRequest(package.scala:57) ~[kamon-datadog_2.13-2.2.0.jar:2.2.0] at kamon.datadog.package$HttpClient.doMethodWithBody(package.scala:65) ~[kamon-datadog_2.13-2.2.0.jar:2.2.0] at kamon.datadog.package$HttpClient.doPut(package.scala:86) ~[kamon-datadog_2.13-2.2.0.jar:2.2.0] at kamon.datadog.package$HttpClient.doJsonPut(package.scala:96) ~[kamon-datadog_2.13-2.2.0.jar:2.2.0] at kamon.datadog.DatadogSpanReporter.reportSpans(DatadogSpanReporter.scala:116) ~[kamon-datadog_2.13-2.2.0.jar:2.2.0] at kamon.module.ModuleRegistry.$anonfun$scheduleSpansBatch$1(ModuleRegistry.scala:217) ~[kamon-core_2.13-2.2.0.jar:2.2.0] at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.scala:18) ~[scala-library-2.13.3.jar:?] at scala.concurrent.Future$.$anonfun$apply$1(Future.scala:671) ~[scala-library-2.13.3.jar:?] at scala.concurrent.impl.Promise$Transformation.run(Promise.scala:430) [scala-library-2.13.3.jar:?] at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) [?:?] at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) [?:?] at java.lang.Thread.run(Thread.java:834) [?:?]
7 replies
Shailesh Patil
I am getting this error Any idea why it could be
Exception in thread "main" java.lang.ClassCastException: class ch.qos.logback.classic.spi.LoggingEvent cannot be cast to class kamon.instrumentation.context.HasContext (ch.qos.logback.classic.spi.LoggingEvent and kamon.instrumentation.context.HasContext are in unnamed module of loader 'app')81ca0ad52ddf4b6f837db7a502939ed0 Exception in thread "main" java.lang.ClassCastException: class ch.qos.logback.classic.spi.LoggingEvent cannot be cast to class kamon.instrumentation.context.HasContext (ch.qos.logback.classic.spi.LoggingEvent and kamon.instrumentation.context.HasContext are in unnamed module of loader 'app')
"io.kamon" %% "kamon-bundle" % 2.2.2 I am using this
I got this error with earlier version 2.1.11
Hi, I am new to kamon. I would like include this project as our akka system metric monitor. i would like to know if I have several nodes, and each of them running with kenela agent, what is the communication mechanism of their communication? are they send actor messages to each other?
Bruno Figueiredo Alves
Hi all, I'm using Akka 2.6 and Kamon 2.x and I pretend to gather metrics from Akka and export them to JMX however I don't think it's possible. Could you help me with this or suggest some workarounds?
High all, have a question about cadinality for Kamon tags. Docs say, avoid high cadinality for "metric-related tags". Does "metric-related tag" here means span#tagMetrics - as opposed to Span#tag ? If yes, can I store high cadinality values in Span#tag without generating time series for each value combination ?
Giridhar Pathak
hey folks, i have an older application built on playframework 2.3. does kamon still support that?
or is there an older version of it i can use?
any direction would be helpful.
Tom Milner
Hey, has anyone experienced missing traces when using scala ZIO? I am using Kamon 2.1.4 with OpenTelemetry, and the app is a bit weird, but I basically have a Akka HTTP API, that runs a ZIO, which in turn calls an Akka HTTP Client (I know this is a weird setup). I see the main trace, and spans for things which happens before the ZIO is run but I do not see the traces for the Client call that happened in the ZIO, and it appears the service that was called did not get the trace ID either. I will keep digging, but if anyone has seen something like that or has an idea what it could be I am all ears.
3 replies
Ivan Topolnjak

@/all hey folks, this is a reminder that we are migrating to Discord for questions and chat related to Kamon. You can join our Discord here: https://discord.gg/5JuYsDJ7au

Have a great week!

Zvi Mints

i cannot find any metrics exposed via kamon-prometheus


kamon.prometheus {
  include-environment-tags = true
  embedded-server {
    hostname =
    port = 9404


class SinkConnector() extends org.apache.kafka.connect.sink.SinkConnector {
  val underlying: AerospikeSinkConnector = new AerospikeSinkConnector()
  override def start(map: util.Map[String, String]): Unit = {
    try {
    catch {
      case ex: Throwable =>
        println(s"Failure on underlying.start($map)")
        Kamon.counter("underlying-start-connector-failure").withTag("config-file",configFile).withTag("message", ex.getMessage).increment()
        throw ex
    finally {


  "io.kamon" %% "kamon-prometheus" % "2.2.2" exclude("org.slf4j", "slf4j-api"),
  "io.kamon" %% "kamon-core" % "2.1.0" exclude("org.slf4j", "slf4j-api")

I already have JMX Exporter which expose Kafka metrics to 9404, i tried to make Kamon use this port also, when i remove the application.conf and use the default value of port 9095 i cannot port-forward to this port for some reason.

I'm missing something?


Zvi Mints
Im getting 2021-08-31 12:03:52,224 WARN Failed to attach the instrumentation because the Kamon Bundle is not present on the classpath (kamon.Init) [connector-thread-dashboard-connector-profile] when i'm using "io.kamon" %% "kamon-prometheus" % "2.2.2" exclude("org.slf4j", "*") - any ideas why?
1 reply
Thomas Jaeckle

Hi. We are experiencing the following WARN message:

Failed to record value [-401488] on [span.processing-time,{operation=serialize,error=false}] because the value is outside of the configured range. The recorded value was adjusted to the highest trackable value [3600000000000]. You might need to change your dynamic range configuration for this metric

So the recorded value is negative. What we use is the Kamon SpanBuilder.start(Instant), however the span is later (within sub-milliseconds) finished via Span.finish() (where the underlying Clock is used to determine the nanos of the finish time)
Could it be that this "mixing" can cause negative values being recorded?

Thomas Jaeckle
ah, maybe instead of Instant.now() we should use Kamon.clock().instant() which provides better precision/performance?
6 replies
Dana Borinski
Trying to add kamon metrics to my caffeine cache, can someone explain please the part of KamonStatCounter or give an example? i see this page in the docs Caffeine.newBuilder().recordStats(() -> new KamonStatsCounter("cache_name")).build(); but not sure i understand what is needed to be passed to the recordStats. i see it expects to get a supplier but this example isnt working so i probably miss something.
Can Kamon instrument the play https connections? We have issue in PROD env where the heap memory increased after we deployed with https enabled. Kamon is throwing java.lang.OutOfMemoryError . I suspect that its because Kamon is not able to scrape the https connections. What is your opinion ?
Isaac Povey
Anyone know how to initialize Kamon with a play application loaded by guice. I followed the play guide but am getting these errors when trying to load it Caused by: java.lang.VerifyError: Expecting a stackmap frame at branch target 102. The application loader looks like this
class CustomApplicationLoader extends GuiceApplicationLoader { override protected def builder(context: Context): GuiceApplicationBuilder = super .builder(context) .eagerlyLoaded()

I am trying to add traceability support to a play 2.8 application with Kamon and Jaeger. I followed [instructions here] (https://kamon.io/docs/latest/reporters/jaeger/) . I am able to see the startup logs for Kanela agent as well as the Jaeger reportes as follows

[info] Running the application with the Kanela agent

 _  __                _        ______
| |/ /               | |       \ \ \ \
| ' / __ _ _ __   ___| | __ _   \ \ \ \
|  < / _` | '_ \ / _ \ |/ _` |   ) ) ) )
| . \ (_| | | | |  __/ | (_| |  / / / /
|_|\_\__,_|_| |_|\___|_|\__,_| /_/_/_/

Running with Kanela, the Kamon Instrumentation Agent :: (v1.0.8)

--- (Running the application, auto-reloading is enabled) ---

[info] p.c.s.AkkaHttpServer - Listening for HTTP on /0:0:0:0:0:0:0:0:9001

(Server started, use Enter to stop and go back to the console...)

2021-09-23 13:29:11,210 [info] [play-dev-mode-akka.actor.default-dispatcher-11] k.i.p.GuiceModule$KamonLoader - Reconfiguring Kamon with Play's Config
2021-09-23 13:29:11,211 [info] [play-dev-mode-akka.actor.default-dispatcher-11] k.i.p.GuiceModule$KamonLoader - play.core.server.AkkaHttpServerProvider
2021-09-23 13:29:11,213 [info] [play-dev-mode-akka.actor.default-dispatcher-11] k.i.p.GuiceModule$KamonLoader - 10 seconds
2021-09-23 13:29:11,573 [info] [play-dev-mode-akka.actor.default-dispatcher-11] k.j.JaegerReporter - Started the Kamon Jaeger reporter

Jaeger is started through a docker container with following command:

docker run -d --name jaeger1   -e COLLECTOR_ZIPKIN_HOST_PORT=:9411   -p 5775:5775/udp   -p 6831:6831/udp   -p 6832:6832/udp   -p 5778:5778   -p 16686:16686   -p 14268:14268   -p 14250:14250   -p 9411:9411   jaegertracing/all-in-one:1.25

None of the traces are visible when I try to access the APIs for my play application. Any configuration I am missing here?

Tommaso Schiavinotto
I'm trying to use Kamon-cassandra (v.2.2.2, kanela 1.0.11) . I'm interested in metrics, but the only one I find available at runtime is span_processing_time_seconds. Is there something I need to configure in order to get those listed in the documentation page?
Giridhar Pathak
hey folks... anyone know if the kanela agent works fine with the openj9 jvm?
i find that my apps has heap going up and then OOMs.
Screen Shot 2021-10-13 at 3.33.16 PM.png
the orange line there is the jvm heap.. the heap was set low.. but the container's mem utilization goes up to 1.5Gb and then OOM
does kanela store data off heap?
and how can i debug this/reduce memory usage.
my conf file:
kamon {
  prometheus {
    embedded-server {
      hostname =
      port = 9095
    buckets {
      time-buckets = [
      information-buckets = [

  instrumentation {

    play {
      server.metrics.enabled = no
      http.server.tracing.enabled = no
      http.client.tracing.enabled = no

  modules.host-metrics.enabled = no
  modules.process-metrics.enabled = no
  modules.status-page.enabled = no
  trace {
    sampler = "never"
    span-metrics = off
    span-metric-tags {
      upstream-service = no
      parent-operation = no

kanela.modules {
  akka {
    enabled = no
  akka-remote {
    enabled = no
  akka-remote-sharding {
    enabled = no
Libor Kramoliš
Hi. Is it possible to exclude selected HTTP endpoints from producing spans? For example, I would like to hide /ready operation because it is called in regular bases by K8s as readiness probe. I do not need to track such operation. Thanks.
1 reply
Sean Glover

good day. i'm having an issue where Kamon is generating strange operation names when there exists an endpoint with more than 1 verb implementation. i'm using guardrail to generate akka-http routes from an openapi spec, and then using Kamon's akka-http server integration. i couldn't find any issues that describe a similar problem, but i thought i would see if anyone here has a pointer.

i.e. i have a GET /foo and POST /foo, an operation name of /foo/foo will be generated for the first defined endpoint from my openapi spec. the second defined endpoint operation name seems unaffected..

1 reply
Sean Glover
i created a reproducer PR: kamon-io/Kamon#1063
Nicolas Vollmar
Hi, with Kamon 2.3.1 we're seeing Cannot register module [akka.io.pinned-dispatcher], a module with that name already exists. popping up in the logs. This wasn't the case with Kamon 2.2.3. The registrations are done by InstrumentNewExecutorServiceOnAkka26.