diff --git a/docs/en/stack/ml/anomaly-detection/troubleshooting.asciidoc b/docs/en/stack/ml/anomaly-detection/troubleshooting.asciidoc index a6780d535..12b73dc66 100644 --- a/docs/en/stack/ml/anomaly-detection/troubleshooting.asciidoc +++ b/docs/en/stack/ml/anomaly-detection/troubleshooting.asciidoc @@ -12,6 +12,7 @@ answers for frequently asked questions. * <> * <> * <> +* <> [[ml-rollingupgrade]] === Machine learning features unavailable after rolling upgrade @@ -113,4 +114,39 @@ If you do not fix or delete the {dfeed} before the upgrade, in order to successf start the failing nodes you must downgrade the nodes then fix the problem per above. -See also {stack-ref}/upgrading-elastic-stack.html[Upgrading the Elastic Stack]. \ No newline at end of file +See also {stack-ref}/upgrading-elastic-stack.html[Upgrading the Elastic Stack]. + +[[ml-debian8-memory]] +=== Suboptimal job assignment on Debian 8 + +Where possible, {ml} jobs are assigned to nodes based on the memory requirement +of the job and the memory available on the node. However, in certain cases, the +amount of memory on a node cannot be accurately determined and jobs are assigned +by balancing the number of jobs per {ml} node. It may lead to a situation where +all the jobs with high memory requirements are on one node and the less +memory-intensive jobs on another. + +One particular case of this problem is that {es} fails to determine the amount +of memory on a machine that is running Debian 8 with the default Cgroups setup +and certain updates of Java versions earlier than Java 15. For example, Java +8u271 is known to be affected while Java 8u272 is not. Java 15 was fixed from +its initial release. + +If you are running {es} on Debian 8 with an old version of Java and have not +already modified the Cgroups setup then it is recommended to do one of the +following: + +* Upgrade Java to version 15. +* Upgrade to the latest Java update for the version of Java you are running. +* Enable the "memory" Cgroup by editing `/etc/default/grub` and adding: ++ +-- +[source,sh] +-------------------------------------------------- +GRUB_CMDLINE_LINUX_DEFAULT="quiet cgroup_enable=memory swapaccount=1" +-------------------------------------------------- + +Update your GRUB configuration by running `sudo update-grub`, then reboot the +machine. + +-- \ No newline at end of file