Hello Vilius, Thanks for your input. 1. When we get set limit of pod, it is much lesser than the node's memory capacity. So, there is no issue of over allocation resulting in OOM. 2. Do we need set both -XX:MaxDirectMemorySize and -Dio.netty.maxDirectMemory or Netty will derive -Dio.netty.maxDirectMemory from -XX:MaxDirectMemorySize? 3. We are using OpenJDK 17 with HotSpot. 4. We will enable netty-allocator and see what data we can extract out of it. Thanks for the hint. 5. Based on your input that "most stable result you should set -XX:MaxDirectMemorySize so that heap + direct memory size never goes above 80-85% of total memory", it appears if we set -XX:MaxDirectMemorySize as 25% of -Xmx, it will be within limit of pod.
Best Regards Shiv -----Original Message----- From: Vilius Šumskas via users <[email protected]> Sent: 16 January 2026 06:36 AM To: [email protected] Cc: Vilius Šumskas <[email protected]> Subject: RE: K8s broker pod getting killed with OOM Unverified Sender: The sender of this email has not been verified. Review the content of the message carefully and verify the identity of the sender before acting on this email: replying, opening attachments or clicking links. That's a little bit off-topic, but would you consider exchanging -Xmx into -XX:MaxRAMPercentage for default configuration in 3.0 too? This would universally improve default JVM memory settings under various scenarios, without the need to change it every time more physical memory is added. And if yes, should I create a ticket for this? -- Vilius -----Original Message----- From: Clebert Suconic <[email protected]> Sent: Thursday, January 15, 2026 12:36 AM To: [email protected] Subject: Re: K8s broker pod getting killed with OOM so, in summary, what I'm recommending you is: use max-size-messages for all the queues.. for your large queues, use something like 10MB and for your small queues 100K also keep max-read-page-bytes in use... keep it at 20M If I could change the past I would have a max-size on every address we deploy, and having global-max-size for the upmost emergency case.. it's something I'm looking to change into artemis 3.0 or 4.0. (I can't change that into a minor version, as it could break certain cases... as some users that I know use heavy filtering and can't really rely on paging). On Wed, Jan 14, 2026 at 5:31 PM Clebert Suconic <[email protected]> wrote: > > I would recommend against trusting global-max-size. and use max-size > for all the addresses. > > Also what is your reading attributes. I would recommending using the > new prefetch values. > > > > And also what operator are you using? arkmq? your own? > > On Wed, Jan 14, 2026 at 7:44 AM Shiv Kumar Dixit > <[email protected]> wrote: > > > > We are hosting Artemis broker in Kubernetes using operator-based solution. > > We deploy the broker as statefulset with 2 or 4 replicas. We assign for > > e.g. 6 GB for heap and 9 GB for pod, 1.2 GB (1/5 of max heap) for > > global-max-size. All addresses normally use -1 for max-size-bytes but some > > less frequently used queues are defined with 100KB for max-size-bytes to > > allow early paging. > > > > > > > > We have following observations: > > > > 1. As the broker pod starts, broker container immediately occupies 6 GB for > > max heap. It seems expected as both min and max heap are same. > > > > 2. Pod memory usage starts with 6+ GB and once we have pending messages, > > good producers and consumers connect to broker, invalid SSL attempts > > happen, broker GUI access happens etc. during normal broker operations - > > pod memory usage keeps increasing and now reaches 9 GB. > > > > 3. Once the pod hits limit of 9 GB, K8s kills the pod with OOMKilling event > > and restarts the pod. Here we don’t see broker container getting killed > > with OOM rather pod is killed and restarted. It forces the broker to > > restart. > > > > 4. We have configured artemis.profile to capture memory dump in case of OOM > > of broker but it never happens. So, we are assuming broker process is not > > going out of memory, but pod is going out of memory due to increased > > non-heap usage. > > > > 5. Only way to recover here is to increase heap and pod memory limits from > > 6 GB and 9 GB to higher values and wait for next re-occurrence. > > > > > > > > 1. Is there any way to analyse what is going wrong with non-heap native > > memory usage? > > > > 2. If non-heap native memory is expected to increase to such extent due to > > pending messages, SSL errors etc.? > > > > 3. Is there any param we can use to restrict the non-heap native memory > > usage? > > > > 4. If netty which handles connection aspect of broker can create such > > memory consumption and cause OOM of pod? > > > > 5. Can we have any monitoring param that can hint that pod is potentially > > in danger of getting killed? > > > > > > > > Thanks > > > > Shiv > > > > -- > Clebert Suconic -- Clebert Suconic --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
