Elastic uses depricated option UseConcMarkSweepGC

[ialidzhikov]

Describe the feature:
A gc deprication warning is being shown.

Elasticsearch version (bin/elasticsearch --version):
6.5.1

Plugins installed: []

JVM version (java -version):

[root@elasticsearch-logging-0 elasticsearch]# /opt/jdk-11.0.1/bin/java -version
openjdk version "11.0.1" 2018-10-16
OpenJDK Runtime Environment 18.9 (build 11.0.1+13)
OpenJDK 64-Bit Server VM 18.9 (build 11.0.1+13, mixed mode)

OS version (uname -a if on a Unix-like system):

[root@elasticsearch-logging-0 elasticsearch]# uname -a
Linux elasticsearch-logging-0 4.14.67-coreos #1 SMP Mon Sep 10 23:14:26 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

Description of the problem including expected versus actual behavior:
We see the current log:

OpenJDK 64-Bit Server VM warning: Option UseConcMarkSweepGC was deprecated in version 9.0 and will likely be removed in a future release.

Steps to reproduce:

Please include a minimal but complete recreation of the problem, including
(e.g.) index creation, mappings, settings, query etc. The easier you make for
us to reproduce it, the more likely that somebody will take the time to look at it.

Provide logs (if relevant):

[dliappis]

Hi @ialidzhikov ,

Since #33685, we optionally support G1GC for Java 10 and above.

However, our default GC engine remains CMS, as Java 1.8 remains a supported runtime and we don't feel confident about supporting G1GC in Java 1.8.

If you wish to stick to G1GC you will need to edit the jvm.options file and uncomment out this section there. You'll still see deprecation warnings (even though G1 will be used) because we enable and disable CMS options in the command line, but if you want to be completely warning-free, then you can just comment out the CMS lines and uncomment out the specific G1GC ones.

[elasticmachine]

Pinging @elastic/es-core-infra

[dliappis]

I will close this issue now, I hope my above reply was helpful, if not, feel free to re-open. Thank you.

[ialidzhikov]

Thank you @dliappis . It was very helpful. Most probably we will test also G1GC.