NIFI-13865: Enable the JVM to record a heap dump when an OOM error occurs

[mattyb149]

Summary

NIFI-13865. This PR adds the following arguments to bootstrap.conf for the NiFi JVM to enable taking a heap dump when an OutOfMemoryError occurs. I'm not sure about the feasibility of unit/integration testing

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  • [x] JDK 21

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[joewitt]

This needs testing in real world deployments before it becomes an always on default. We've used this many times in the past but there was always some reason to avoid it being there as a default.

[mattyb149]

Makes sense, I'll add them commented out with some doc

[joewitt]

good idea @exceptionfactory. In general getting our out of the box files simpler/less options and then documenting how to do things would yield a better user experience.

[mattyb149]

I can add it to the Admin Guide too, but for folks supporting other NiFi users, it just seems easier to ask the user(s) to uncomment a couple of existing lines vs having them search in the Guide for something that they might not know they're looking for, mis-copying the text from the Guide, etc.

[exceptionfactory]

I can add it to the Admin Guide too, but for folks supporting other NiFi users, it just seems easier to ask the user(s) to uncomment a couple of existing lines vs having them search in the Guide for something that they might not know they're looking for, mis-copying the text from the Guide, etc.

I agree this is a fine line, but over the years, the default configuration files have grown to include lot of commented information and many defaults that rarely change. In this case, the security implications and potential disk utilization concerns surrounding heap dumps make me think this should not be included in the default bootstrap.conf, even as a commented option.

[exceptionfactory]

It is also worth noting that the while the default configuration files should be minimal, nothing prevents others from providing alternative defaults in customized packages. The goal of the default files, however, should be to provide sensible and secure defaults without overwhelming users.

[mattyb149]

I was using the debug and javaAgent entries as an example.

[exceptionfactory]

I agree the debug and javaAgent examples are notable. There are other common production-level options we could consider, such as maximum directory memory usage, and other memory settings, but these are more specific to given environments, and harder to generalize. That's where having a section of the Admin Guide, with copyable examples, seems like a better way to go more for more JVM options.

[mattyb149]

Ok I will change this PR/Jira to add this to the Admin Guide instead

[joewitt]

Due to comments about the nature of this PR subject to change going to close for now. Please open a new one as available.