# Akka Libraries **URL:** https://discuss.akka.io/c/akka/5.md [Latest](https://discuss.akka.io/latest.md) · [Categories](https://discuss.akka.io/categories.md) · [Tags](https://discuss.akka.io/tags.md) --- ## [About the Akka Libraries category](https://discuss.akka.io/t/about-the-akka-libraries-category/13)
**Author:** [@ktoso](https://discuss.akka.io/u/ktoso)\ **Replies:** 0\ **Last updated:** [February 9, 2018, 10:52am UTC](https://discuss.akka.io/t/about-the-akka-libraries-category/13 "2018-02-09T10:52:42Z")
This forum is now read-only. Please contact our support at support@akka.io --- ## [OpenTelemetry Setup for the new Akka Java SDK](https://discuss.akka.io/t/opentelemetry-setup-for-the-new-akka-java-sdk/11663)
**Author:** [@theleoborges](https://discuss.akka.io/u/theleoborges)\ **Replies:** 9\ **Last updated:** [August 26, 2025, 9:31am UTC](https://discuss.akka.io/t/opentelemetry-setup-for-the-new-akka-java-sdk/11663 "2025-08-26T09:31:26Z")
As per the docs, here’s how I setup my SDK: akka.javasdk { agent { model-provider = openai openai { model-name = "gpt-4o-mini" api-key = ${?OPENAI\_API\_KEY} } } telemetry { tracing { … --- ## [A Conceptual Model of "Varying Inertia" (NKTg Law) — Could Akka Simulate Physical Dynamics?](https://discuss.akka.io/t/a-conceptual-model-of-varying-inertia-nktg-law-could-akka-simulate-physical-dynamics/11643)
**Author:** [@NKTgLaw](https://discuss.akka.io/u/NKTgLaw)\ **Replies:** 0\ **Last updated:** [August 14, 2025, 6:27am UTC](https://discuss.akka.io/t/a-conceptual-model-of-varying-inertia-nktg-law-could-akka-simulate-physical-dynamics/11643 "2025-08-14T06:27:45Z")
Hi everyone, I’d like to introduce a conceptual framework—the NKTg Law—that models how an object’s motion changes when mass varies over time. I’m curious if Akka (especially Akka Streams or typed actors) could be a good… --- ## [Partial Event Sourcing](https://discuss.akka.io/t/partial-event-sourcing/11634)
**Author:** [@tnichollcnc](https://discuss.akka.io/u/tnichollcnc)\ **Replies:** 0\ **Last updated:** [August 7, 2025, 3:17pm UTC](https://discuss.akka.io/t/partial-event-sourcing/11634 "2025-08-07T15:17:38Z")
Looking for some feedback on an idea that I’m calling “Partial Event Sourcing”. Suppose you have some complex state S built from a stream of events of type E1 or E2. E1 are regular, persisted events like we are familiar… --- ## [Error downloading io.akka:sbt-paradox-akka NOT FOUND](https://discuss.akka.io/t/error-downloading-io-akka-sbt-paradox-akka-not-found/11536)
**Author:** [@python3js](https://discuss.akka.io/u/python3js)\ **Replies:** 1\ **Last updated:** [July 14, 2025, 3:19pm UTC](https://discuss.akka.io/t/error-downloading-io-akka-sbt-paradox-akka-not-found/11536 "2025-07-14T15:19:04Z")
I cloned the prjoect akka-persistence-dynamodb on my machine and created the file akka.sbt in the root directory: ThisBuild / resolvers += "akka-secure-mvn" at "https://repo.akka.io/\/secure" ThisBuild / re… --- ## [Reusability of Sources in Akka Streams](https://discuss.akka.io/t/reusability-of-sources-in-akka-streams/11532)
**Author:** [@kstokoz](https://discuss.akka.io/u/kstokoz)\ **Replies:** 2\ **Last updated:** [August 4, 2025, 8:33am UTC](https://discuss.akka.io/t/reusability-of-sources-in-akka-streams/11532 "2025-08-04T08:33:36Z")
The Akka Streams docs (Basics and working with Flows • Akka Documentation) mention that Sources can be reused (i.e., materialized multiple times), but I’ve seen cases where this doesn’t work — for example: Source.fromI… --- ## [Is it possible to check existence of persistent entity by it's id?](https://discuss.akka.io/t/is-it-possible-to-check-existence-of-persistent-entity-by-its-id/11521)
**Author:** [@shamoh](https://discuss.akka.io/u/shamoh)\ **Replies:** 1\ **Last updated:** [June 19, 2025, 6:51am UTC](https://discuss.akka.io/t/is-it-possible-to-check-existence-of-persistent-entity-by-its-id/11521 "2025-06-19T06:51:05Z")
Hello. I have a persistent entity, and in my use-case I need to handle a lot of requests with ID that do NOT represent an existing entity. There are millions of entities with unique ID. And just about 0.01 % of regular… --- ## [TLS connection not establishing after introducing new customsslengine class](https://discuss.akka.io/t/tls-connection-not-establishing-after-introducing-new-customsslengine-class/11501)
**Author:** [@Ganeshram91](https://discuss.akka.io/u/Ganeshram91)\ **Replies:** 0\ **Last updated:** [June 11, 2025, 7:00am UTC](https://discuss.akka.io/t/tls-connection-not-establishing-after-introducing-new-customsslengine-class/11501 "2025-06-11T07:00:15Z")
I have created new scala class for introducing customsslengine as below package akka.osgi; import akka.actor.ActorSystem import akka.event.{Logging, LoggingAdapter} import akka.remote.artery.tcp.ConfigSSLEngineProvid… --- ## [TCP Connection between akka cluster nodes](https://discuss.akka.io/t/tcp-connection-between-akka-cluster-nodes/11488)
**Author:** [@vkp096](https://discuss.akka.io/u/vkp096)\ **Replies:** 2\ **Last updated:** [July 26, 2025, 11:37am UTC](https://discuss.akka.io/t/tcp-connection-between-akka-cluster-nodes/11488 "2025-07-26T11:37:41Z")
akkaVersion =‘2.6.21’ two hosts containing two akka jvms which are supposed to be clustering is not working due to the following error seen in seed-node error log running in linux machine: 2025-06-03 23:43:11,209 WARN… --- ## [Is there any way to support Multiple TLS protocol versions to support backward compatability in akka via application.conf](https://discuss.akka.io/t/is-there-any-way-to-support-multiple-tls-protocol-versions-to-support-backward-compatability-in-akka-via-application-conf/11476)
**Author:** [@Ganeshram91](https://discuss.akka.io/u/Ganeshram91)\ **Replies:** 1\ **Last updated:** [June 3, 2025, 4:56pm UTC](https://discuss.akka.io/t/is-there-any-way-to-support-multiple-tls-protocol-versions-to-support-backward-compatability-in-akka-via-application-conf/11476 "2025-06-03T16:56:27Z")
Is there any way to support Multiple TLS protocol versions to support backward compatability in akka via application.conf for example both, \[“TLSv1.2”, “TLSv1.3”\] --- ## [Which akka package to add in logback xml in the application to see TLS exceptions when TLS version mismatch found between provider and consumer](https://discuss.akka.io/t/which-akka-package-to-add-in-logback-xml-in-the-application-to-see-tls-exceptions-when-tls-version-mismatch-found-between-provider-and-consumer/11475)
**Author:** [@Ganeshram91](https://discuss.akka.io/u/Ganeshram91)\ **Replies:** 1\ **Last updated:** [June 3, 2025, 5:09pm UTC](https://discuss.akka.io/t/which-akka-package-to-add-in-logback-xml-in-the-application-to-see-tls-exceptions-when-tls-version-mismatch-found-between-provider-and-consumer/11475 "2025-06-03T17:09:19Z")
Which akka package to add in logback xml in the application to log and see TLS exceptions or TLS connection establishment failures when TLS version mismatch found between provider and consumer. we were using karaf envir… --- ## [Support for Multiple Protocols in AKKA Remote Artery SSL Configuration](https://discuss.akka.io/t/support-for-multiple-protocols-in-akka-remote-artery-ssl-configuration/11468)
**Author:** [@arun.t](https://discuss.akka.io/u/arun.t)\ **Replies:** 1\ **Last updated:** [May 28, 2025, 6:08am UTC](https://discuss.akka.io/t/support-for-multiple-protocols-in-akka-remote-artery-ssl-configuration/11468 "2025-05-28T06:08:15Z")
I’ve been reviewing the AKKA documentation, and it doesn’t explicitly state whether akka - remote.artery.ssl can support multiple protocols in its configuration. For instance, setting protocol = \["TLSv1.2", "TLSv1.3"\]. D… --- ## [Offsetstore timeuuidoffset is not being updated](https://discuss.akka.io/t/offsetstore-timeuuidoffset-is-not-being-updated/11445)
**Author:** [@Gervais](https://discuss.akka.io/u/Gervais)\ **Replies:** 2\ **Last updated:** [July 4, 2025, 5:06pm UTC](https://discuss.akka.io/t/offsetstore-timeuuidoffset-is-not-being-updated/11445 "2025-07-04T17:06:01Z")
Hello Everyone, I have an issue since days and I don’t understand the root cause. I’m using Lagom and here are the relevant versions: Lagom 1.6.0 akka 2.6.9 akka-http 10.1.11 akka-persistence-cassandra 0.101 Events … --- ## [Rolling Update with Remember Entites issue with newer Writer](https://discuss.akka.io/t/rolling-update-with-remember-entites-issue-with-newer-writer/11432)
**Author:** [@KDSBest](https://discuss.akka.io/u/KDSBest)\ **Replies:** 2\ **Last updated:** [May 7, 2025, 8:34am UTC](https://discuss.akka.io/t/rolling-update-with-remember-entites-issue-with-newer-writer/11432 "2025-05-07T08:34:42Z")
Hi everyone, if I perform a rolling Update with Remember-Entities on then the new node get plenty of errors from this line of code: val errMsg = s"Invalid replayed event \[sequenceNr=${r.persistent.sequenceNr}, writerUU… --- ## [Optional scalapb serialization binding breaks existing mapping](https://discuss.akka.io/t/optional-scalapb-serialization-binding-breaks-existing-mapping/11352)
**Author:** [@bekiroguz](https://discuss.akka.io/u/bekiroguz)\ **Replies:** 2\ **Last updated:** [March 26, 2025, 8:22am UTC](https://discuss.akka.io/t/optional-scalapb-serialization-binding-breaks-existing-mapping/11352 "2025-03-26T08:22:49Z")
Hi there, related to this feature in 2.9.0 release: feat: Optionally include serialization binding for ScalaPb by patriknw · Pull Request #32070 · akka/akka · GitHub I see that starting from akka 2.9.0, an optional ser… --- ## [Issue with EventProducerSource in app with many event sourced entitites](https://discuss.akka.io/t/issue-with-eventproducersource-in-app-with-many-event-sourced-entitites/11346)
**Author:** [@Mitep](https://discuss.akka.io/u/Mitep)\ **Replies:** 5\ **Last updated:** [March 24, 2025, 7:19am UTC](https://discuss.akka.io/t/issue-with-eventproducersource-in-app-with-many-event-sourced-entitites/11346 "2025-03-24T07:19:12Z")
Hello, I’m developing the Akka application using Event Sourcing in Cluster and Projections. I started the project using the examples given in Akka’s examples on GitHub. This is how the project looks: Event sourced Wo… --- ## [A problem with cinnamon instrumenting akka streams](https://discuss.akka.io/t/a-problem-with-cinnamon-instrumenting-akka-streams/11345)
**Author:** [@xeppaka](https://discuss.akka.io/u/xeppaka)\ **Replies:** 2\ **Last updated:** [March 18, 2025, 7:22am UTC](https://discuss.akka.io/t/a-problem-with-cinnamon-instrumenting-akka-streams/11345 "2025-03-18T07:22:50Z")
Hi, I’m using cinnamon for collecting metrics from akka streams and faced a weird behavior of the cinnamon library when RestartSource, RestartFlow or RestartSink is used. Basically the problem is that only RestartXXX ope… --- ## [Akka Memory Leak Issue](https://discuss.akka.io/t/akka-memory-leak-issue/11332)
**Author:** [@selim](https://discuss.akka.io/u/selim)\ **Replies:** 4\ **Last updated:** [March 26, 2025, 8:19pm UTC](https://discuss.akka.io/t/akka-memory-leak-issue/11332 "2025-03-26T20:19:09Z")
I’ve observed that the memory usage of the Akka Cluster nodes continuously increases, which eventually leads to pod restarts after a certain period. I can clearly see this trend while monitoring the memory usage. I’ve at… --- ## [License key within Playframework](https://discuss.akka.io/t/license-key-within-playframework/11301)
**Author:** [@gervaisb](https://discuss.akka.io/u/gervaisb)\ **Replies:** 2\ **Last updated:** [February 20, 2025, 11:21pm UTC](https://discuss.akka.io/t/license-key-within-playframework/11301 "2025-02-20T23:21:04Z")
Hello there, We are (finally) migrating to Akka 2.10+ in our web application backed by Playframework. Unfortunately, we do have a strange behavior with the akka.license-key configuration. We can give it via the JVM op… --- ## [Alpakka google-cloud-pub-sub for Scala 3?](https://discuss.akka.io/t/alpakka-google-cloud-pub-sub-for-scala-3/11241)
**Author:** [@jacob](https://discuss.akka.io/u/jacob)\ **Replies:** 3\ **Last updated:** [February 17, 2025, 4:43am UTC](https://discuss.akka.io/t/alpakka-google-cloud-pub-sub-for-scala-3/11241 "2025-02-17T04:43:09Z")
Is that in the plans? --- ## [Why/When would EventsByTagStage receive multiple pubsub notifications within the defined interval?](https://discuss.akka.io/t/why-when-would-eventsbytagstage-receive-multiple-pubsub-notifications-within-the-defined-interval/11180)
**Author:** [@pertsodian](https://discuss.akka.io/u/pertsodian)\ **Replies:** 1\ **Last updated:** [January 17, 2025, 3:19am UTC](https://discuss.akka.io/t/why-when-would-eventsbytagstage-receive-multiple-pubsub-notifications-within-the-defined-interval/11180 "2025-01-17T03:19:56Z")
We are using akka-persistence-cassandra v0.103 with the following configurations cassandra-journal.pubsub-notification = 3s cassandra-query-journal.refresh-interval = 10s cassandra-query-journal.events-by-tag.eventual-c… --- ## [ActorCluster bootstrap not starting properly . java.lang.NoClassDefFoundError: akka/http/scaladsl/model/Uri$](https://discuss.akka.io/t/actorcluster-bootstrap-not-starting-properly-java-lang-noclassdeffounderror-akka-http-scaladsl-model-uri/11179)
**Author:** [@arunak18](https://discuss.akka.io/u/arunak18)\ **Replies:** 1\ **Last updated:** [January 22, 2025, 8:16am UTC](https://discuss.akka.io/t/actorcluster-bootstrap-not-starting-properly-java-lang-noclassdeffounderror-akka-http-scaladsl-model-uri/11179 "2025-01-22T08:16:29Z")
When i tried to implement a ActorCluster formation with akka 2.5.32. I have used akka-discovery\_2.11-2.5.32.jar akka-http\_2.11-10.1.15.jar akka-management\_2.11-1.0.10.jar akka-management-cluster-bootstrap\_2.11-1.0.10.j… --- ## [Downing an unreachable node via akka management doesn't solve the unreachability](https://discuss.akka.io/t/downing-an-unreachable-node-via-akka-management-doesnt-solve-the-unreachability/11177)
**Author:** [@ZeinaH](https://discuss.akka.io/u/ZeinaH)\ **Replies:** 3\ **Last updated:** [January 21, 2025, 1:37pm UTC](https://discuss.akka.io/t/downing-an-unreachable-node-via-akka-management-doesnt-solve-the-unreachability/11177 "2025-01-21T13:37:44Z")
Hello, we have a cluster of 5 nodes and we use akka 2.8.6. We do not use the auto-downing feature but instead we down unreachable nodes via akka management. Today a node in our cluster became unreachable to all other 4… --- ## [Continue buffering new messages when underlying persistence plugin throw ex](https://discuss.akka.io/t/continue-buffering-new-messages-when-underlying-persistence-plugin-throw-ex/11169)
**Author:** [@Charles](https://discuss.akka.io/u/Charles)\ **Replies:** 1\ **Last updated:** [January 7, 2025, 7:49am UTC](https://discuss.akka.io/t/continue-buffering-new-messages-when-underlying-persistence-plugin-throw-ex/11169 "2025-01-07T07:49:06Z")
I have some eventSourcedBehaviour setup as a cluster. And im uisng r2dbc plugin with postgres for both the journal and snapshot. when I simulate the failure of postgres(by switching it completely off), i first get this… --- ## [Build akka 2.6.9](https://discuss.akka.io/t/build-akka-2-6-9/11166)
**Author:** [@lzy-1997](https://discuss.akka.io/u/lzy-1997)\ **Replies:** 2\ **Last updated:** [February 1, 2025, 3:54pm UTC](https://discuss.akka.io/t/build-akka-2-6-9/11166 "2025-02-01T15:54:44Z")
How to build Akka 2.6.9 by using the source code in the Github. I try to build it, but it can not get some plugin dependencies in JFrog. Has anyone encountered this issue? --- ## [Best Practices for Scaling Akka Actors in a High Throughput System](https://discuss.akka.io/t/best-practices-for-scaling-akka-actors-in-a-high-throughput-system/11155)
**Author:** [@harryson614](https://discuss.akka.io/u/harryson614)\ **Replies:** 2\ **Last updated:** [February 1, 2025, 11:01am UTC](https://discuss.akka.io/t/best-practices-for-scaling-akka-actors-in-a-high-throughput-system/11155 "2025-02-01T11:01:19Z")
Hello Akka community, I’m currently working on a high-throughput system using Akka, and I’m seeking advice on best practices for scaling Akka actors in a way that ensures both performance and reliability. The system nee… --- ## [Alpakka connector](https://discuss.akka.io/t/alpakka-connector/11068)
**Author:** [@hamid](https://discuss.akka.io/u/hamid)\ **Replies:** 2\ **Last updated:** [November 24, 2024, 1:27pm UTC](https://discuss.akka.io/t/alpakka-connector/11068 "2024-11-24T13:27:14Z")
Hi, I am very new to Apache Kafka and kafka stream. I have a few questions: Does Apache Kafka Server has built in alpakka kafka connector My Javascript application sends messages (producer) to Apache Kafka server on po… --- ## [Why the remote Akka nodes become unreachable however the network is reachable?](https://discuss.akka.io/t/why-the-remote-akka-nodes-become-unreachable-however-the-network-is-reachable/11064)
**Author:** [@zhangmroy](https://discuss.akka.io/u/zhangmroy)\ **Replies:** 5\ **Last updated:** [December 28, 2024, 4:41pm UTC](https://discuss.akka.io/t/why-the-remote-akka-nodes-become-unreachable-however-the-network-is-reachable/11064 "2024-12-28T16:41:30Z")
Hi, I would like to rebuild my ODL clusters on the overlay network. the cluster before: these nodes connect each other on the underlay network(11.128.85.27, 11.128.85.58, 11.128.85.79), and the cluster works well … --- ## [Alpakka SE3 Connectors support with Ceph](https://discuss.akka.io/t/alpakka-se3-connectors-support-with-ceph/11045)
**Author:** [@Susmit07](https://discuss.akka.io/u/Susmit07)\ **Replies:** 1\ **Last updated:** [November 11, 2024, 6:24pm UTC](https://discuss.akka.io/t/alpakka-se3-connectors-support-with-ceph/11045 "2024-11-11T18:24:54Z")
Hello Fellow Engineers, I am having a basic question, currently we are using Alpakka S3 connectors with Cloudian S3, do we support Ceph as well Thanks, Susmit --- ## [Best way to pause an actor command and retry it without blocking the actor](https://discuss.akka.io/t/best-way-to-pause-an-actor-command-and-retry-it-without-blocking-the-actor/11039)
**Author:** [@ernleite](https://discuss.akka.io/u/ernleite)\ **Replies:** 1\ **Last updated:** [November 7, 2024, 12:48pm UTC](https://discuss.akka.io/t/best-way-to-pause-an-actor-command-and-retry-it-without-blocking-the-actor/11039 "2024-11-07T12:48:35Z")
hello, I am trying to find the best way to pause an actor command and retry it without blocking the actor itselt. Basically events are filling a hashtable and I need to wait until a specific index of my table is receive… [Next page](https://discuss.akka.io/c/akka/5.md?page=1)