Catching core files in read-only jails

[Terje Elde]

> On 01 Apr 2016, at 06:45, J David <j.david.lists at gmail.com> wrote:
> 
> If an application is running on a production server in a read-only
> jail for security purposes, and it crashes occasionally due to some
> unknown bug, is there any way to catch a core file?

Wherever you allow it to write core files, would be writable by the jail, at least those files. It's tempting to recommend a single writable, but no-exec and no-suid dir inside the jail, and point cores there. It's an easy fix, and the alternative - allow writes outside the jail - probably isn't any better.

If you're concerned about something being persisted in the jail, you can wipe or even recreate that dir whenever you're starting the jail. 

Terje