If the underlying mount point for the JNA temporary directory is mounted
noexec on Linux, then the JVM will not be able to map the native code in
as executable. This will prevent JNA from executing and will prevent
Elasticsearch from being able to execute some functions that rely on
native code (e.g., memory locking, and installing system call
filters). We do not want to get into the business of catching exceptions
and parsing messages towards this because these exception messages can
change on us. We also do not want to jump through a lot of hoops to
check the underlying mount point for noexec. Instead, we will rely on
documentation to address this problem. This commit adds to the important
system configuration section of the docs that the JNA temporary
directory is not on a mount point with the noexec mount option.
This commit reorganizes some of the content in the configuring
Elasticsearch section of the docs. The changes are:
- move JVM options out of system configuration into configuring
Elasticsearch
- move JVM options to its own page of the docs
- move configuring the heap to important Elasticsearch settings
- move configuring the heap to its own page of the docs
- move all important settings to individual pages in the docs
- remove bootstrap.memory_lock from important settings, this is covered
in the swap section of system configuration
Relates #27755
When these docs were moved they should have been moved to the system
configuration docs. This commit does that, and also fixes a missing
heading that broke the docs build.
James Rodewig
Jason Tedor
Clinton Gormley