Add ruby function to merge JVM options

[roborourke]

Fixes #22

Right now using deep_merge results in the JVM options array being overwritten completely. The default options added since updating this module to use elasticstack and Java 11 result in the service not being able to start depending on the version of Elasticsearch selected.

This ensures that the default JVM options are scoped to the Java versions they work with and that any overrides do not cause these safe defaults to be overwritten completely unless it is intentional.

The update is backwards compatible with installations that set the -Xmx and -Xms JVM options using the legacy method and adds a new simpler option memory that will set these options for you.

[BronsonQuick]

My first test with the following config failed:

extensions:
  - chassis/chassis_elasticsearch
elasticsearch:
  repo_version: 6.x
  version: 6.3.1
  plugins: [analysis-icu, ingest-attachment]
virtualbox:
  memory: 2048

The logs show that it's because of the following error:
Unrecognized VM option 'PrintGCDateStamps'

cat /etc/elasticsearch/es/jvm.options shows the following config:

# This file is managed by Puppet -- es
#
# Set the 'jvm_options' parameter on the elasticsearch class to change this file.

-Dfile.encoding=UTF-8
-Dio.netty.noKeySetOptimization=true
-Dio.netty.noUnsafe=true
-Dio.netty.recycler.maxCapacityPerThread=0
-Djava.awt.headless=true
-Djna.nosys=true
-Dlog4j.shutdownHookEnabled=false
-Dlog4j2.disable.jmx=true
-XX:+AlwaysPreTouch
-XX:+HeapDumpOnOutOfMemoryError
-XX:+PrintGCDateStamps
-XX:+PrintGCDetails
-XX:+PrintTenuringDistribution
-XX:+UseCMSInitiatingOccupancyOnly
-XX:+UseConcMarkSweepGC
-XX:+UseGCLogFileRotation
-XX:-OmitStackTraceInFastThrow
-XX:CMSInitiatingOccupancyFraction=75
-XX:GCLogFileSize=64m
-XX:NumberOfGCLogFiles=32
-Xloggc:/var/log/elasticsearch/es/gc.log
-Xms2g
-Xmx2g
-Xss1m
-server

[roborourke]

Well that’s not right! From a clean install? I’ll try it again.

[BronsonQuick]

Yeah that was from a fresh install and I also tried a provision as well. It was still getting the defaults from the ES puppet class.

[roborourke]

Herp derp - if you passed no jvm_options it was matching all the defaults and stripping them out. I updated the function to allow all defaults if the passed options array is empty.

Tested and this works now with the following:

extensions:
  - chassis/chassis_elasticsearch
elasticsearch:
  repo_version: 6.x
  version: 6.3.1
  plugins: [analysis-icu, ingest-attachment]
virtualbox:
  memory: 2048

and

extensions:
  - chassis/chassis_elasticsearch
elasticsearch:
  repo_version: 6.x
  version: 6.3.1
  plugins: [analysis-icu, ingest-attachment]
  memory: 1024
virtualbox:
  memory: 2048

and

extensions:
  - chassis/chassis_elasticsearch
elasticsearch:
  jvm_options:
    - '-Xmx512m'
    - '-Xms512m'

[roborourke]

For reference this was breaking using the disabled_extensions feature with this extension

[BronsonQuick]

Oohh let me dig into this one and open an issue to fix it! Thanks for letting me know!

[BronsonQuick]

Nice one! We're back in action now. Thank you Sir!