rage1337 opened a new issue, #6233:
URL: https://github.com/apache/camel-k/issues/6233
### What happened?
We are trying run a netty to mqtt integration. Our platform is OpenShift
4.16 and Camel K v2.7.0 installed via the operator.
The use case is very simple:
```
kamel run \
--trait container.request-cpu=2 \
--trait container.limit-cpu=4 \
--trait container.request-memory=1Gi \
--trait container.limit-memory=4Gi \
--trait jvm.options=-Xms512m \
--trait jvm.options=-Xmx1g \
--trait jvm.options=-XX:MaxDirectMemorySize=1g \
--trait jvm.options=-Dio.netty.maxDirectMemory=536870912 \
--trait jvm.options=-Dio.netty.allocator.numDirectArenas=4 \
--trait jvm.options=-Dio.netty.allocator.maxOrder=7 \
--trait jvm.options=-XX:MaxMetaspaceSize=256m \
--trait jvm.options=-XshowSettings:vm \
--trait jvm.options=-XX:+PrintFlagsFinal \
--trait jvm.options=-Dio.netty.leakDetectionLevel=advanced \
--trait jvm.options=-Dcom.sun.management.jmxremote \
--trait jvm.options=-Dcom.sun.management.jmxremote.port=7091 \
--trait jvm.options=-Dcom.sun.management.jmxremote.rmi.port=7091 \
--trait jvm.options=-Dcom.sun.management.jmxremote.local.only=false \
--trait jvm.options=-Dcom.sun.management.jmxremote.authenticate=false \
--trait jvm.options=-Dcom.sun.management.jmxremote.ssl=false \
--trait logging.level=DEBUG \
--trait jvm.options=-Djava.rmi.server.hostname=127.0.0.1 \
--config configmap:camel-k-transformation-file test08.xml
```
test08.xml looks as follows:
```
<routes xmlns="http://camel.apache.org/schema/spring";>
<route id="bitstream-route">
<from
uri="netty:[tcp://abc-service.kamel-example.svc.cluster.local:10002?clientMode=true&textline=true&sync=false&decoderMaxLineLength=5000000&delimiter=LINE&allowDefaultCodec=false](tcp://scampiqgen-service.kamel-example.svc.cluster.local:10002?clientMode=true&textline=true&sync=false&decoderMaxLineLength=5000000&delimiter=LINE&allowDefaultCodec=false)"/>
<filter>
<simple>${body} == null</simple>
<stop/>
</filter>
<to
uri="[paho-mqtt5:theQueue?userName=abc&password=abc&brokerUrl=tcp://mosquitto-service.kamel-example.svc.cluster.local:11883](paho-mqtt5:theQueue?userName=abc&password=abc&brokerUrl=tcp://mosquitto-service.kamel-example.svc.cluster.local:11883)"/>
</route>
</routes>
```
This results in an OOM after a while with the following stack trace:
```
2025-08-19 09:41:50,519 WARN
[org.apa.cam.com.net.NettyConsumerExceptionHandler] (Camel (camel-1) thread #6
- NettyConsumerExecutorGroup) Closing channel as an exception was thrown from
Netty. Caused by: [java.lang.OutOfMemoryError - Cannot reserve 65536 bytes of
direct buffer memory (allocated: 1073709164, limit: 1073741824)]:
java.lang.OutOfMemoryError: Cannot reserve 65536 bytes of direct buffer memory
(allocated: 1073709164, limit: 1073741824)
at java.base/java.nio.Bits.reserveMemory(Bits.java:178)
at java.base/java.nio.DirectByteBuffer.<init>(DirectByteBuffer.java:121)
at java.base/java.nio.ByteBuffer.allocateDirect(ByteBuffer.java:332)
at
io.netty.buffer.PoolArena$DirectArena.allocateDirect(PoolArena.java:718)
at io.netty.buffer.PoolArena$DirectArena.newChunk(PoolArena.java:693)
at io.netty.buffer.PoolArena.allocateNormal(PoolArena.java:213)
at io.netty.buffer.PoolArena.tcacheAllocateNormal(PoolArena.java:195)
at io.netty.buffer.PoolArena.allocate(PoolArena.java:137)
at io.netty.buffer.PoolArena.allocate(PoolArena.java:127)
at
io.netty.buffer.PooledByteBufAllocator.newDirectBuffer(PooledByteBufAllocator.java:403)
at
io.netty.buffer.AbstractByteBufAllocator.directBuffer(AbstractByteBufAllocator.java:188)
at
io.netty.buffer.AbstractByteBufAllocator.directBuffer(AbstractByteBufAllocator.java:179)
at
io.netty.buffer.AbstractByteBufAllocator.ioBuffer(AbstractByteBufAllocator.java:140)
at
io.netty.channel.DefaultMaxMessagesRecvByteBufAllocator$MaxMessageHandle.allocate(DefaultMaxMessagesRecvByteBufAllocator.java:120)
at
io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:150)
at
io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:796)
at
io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:732)
at
io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:658)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:562)
at
io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:998)
at
io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
at java.base/java.lang.Thread.run(Thread.java:840)
```
<img width="2296" height="1181" alt="Image"
src="https://github.com/user-attachments/assets/0fb8c5a2-d0bb-4727-909a-8f1ba4ec3b8c";
/>
Increasing the memory of the pod just prolongs the time until this hits.
We experimented with various flags, but did not come to a solution that
works over time.
We found [this medium
article](https://medium.com/@asafmesika/a-netty-bytebuf-memory-leak-story-and-lessons-learned-e715aeb0d275)
but are unsure if this is the same problem.
### Steps to reproduce
_No response_
### Relevant log output
```shell
```
### Camel K version
v2.7.0
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