Today when parsing settings during bootstrap, we add a system property
for every Elasticsearch setting. Additionally, settings can be set via
system properties. This commit simplifies this situation.
- settings are no longer propogated to system properties
- system properties can not be used to set settings
- the "es." prefix on settings is no longer required (nor permitted)
- test logging has a dedicated system property (tests.logger.level)
Relates #18198
This commit adds a hard requirement to the RPM and Debian packages for
/bin/bash to be present, and adds a note regarding this to the migration
docs.
Relates #18259
This commit adds a new configuration file jvm.options to centralize and
simplify management of JVM options. This separates the configuration of
the JVM from the packaging scripts (bin/elasticsearch*, bin/service.bat,
and init.d/elasticsearch) simplifying end-user operational management of
custom JVM options.