From d9e34bff2f120a365ab17c8245ce06c3b48317f2 Mon Sep 17 00:00:00 2001
From: Andrea Dell'Amico <adellam@isti.cnr.it>
Date: Wed, 26 Sep 2018 19:24:44 +0200
Subject: [PATCH] library/roles/ELK/elasticsearch: Compatibility changes so
 that we can run ES 6.

---
 ELK/elasticsearch/defaults/main.yml           |  2 ++
 .../templates/elasticsearch-default.j2        |  2 ++
 .../templates/elasticsearch.yml.j2            |  6 ++++
 ELK/elasticsearch/templates/jvm.options.j2    | 30 +++++++++++++++++++
 4 files changed, 40 insertions(+)

diff --git a/ELK/elasticsearch/defaults/main.yml b/ELK/elasticsearch/defaults/main.yml
index 4dade06..edaf36c 100644
--- a/ELK/elasticsearch/defaults/main.yml
+++ b/ELK/elasticsearch/defaults/main.yml
@@ -26,6 +26,8 @@ elasticsearch_define_heap_size: False
 elasticsearch_heap_size: 2g
 elasticsearch_additional_java_opts: '-server -Djava.awt.headless=true'
 elasticsearch_max_open_files: 65536
+# Compatibility with kernels <= 3.5. Set to False if you are using a newer kernel
+elasticsearch_disable_bootstrap_syscall_filter: True
 
 # bin/plugin for 2.x, bin/elasticsearch-plugin for 5.x
 #elasticsearch_plugin_bin: /usr/share/elasticsearch/bin/elasticsearch-plugin
diff --git a/ELK/elasticsearch/templates/elasticsearch-default.j2 b/ELK/elasticsearch/templates/elasticsearch-default.j2
index 8f1ff17..9fc9bfb 100644
--- a/ELK/elasticsearch/templates/elasticsearch-default.j2
+++ b/ELK/elasticsearch/templates/elasticsearch-default.j2
@@ -46,8 +46,10 @@ ES_JAVA_OPTS="{{ elasticsearch_additional_java_opts }}"
 # Note that this setting is only used by the init script. If changed, make sure that
 # the configured user can read and write into the data, work, plugins and log directories.
 # For systemd service, the user is usually configured in file /usr/lib/systemd/system/elasticsearch.service
+{% if elasticsearch_major_version < 6 %}
 ES_USER=elasticsearch
 ES_GROUP=elasticsearch
+{% endif %}
 
 # The number of seconds to wait before checking if Elasticsearch started successfully as a daemon process
 ES_STARTUP_SLEEP_TIME=5
diff --git a/ELK/elasticsearch/templates/elasticsearch.yml.j2 b/ELK/elasticsearch/templates/elasticsearch.yml.j2
index 0858b9e..4fe54c0 100644
--- a/ELK/elasticsearch/templates/elasticsearch.yml.j2
+++ b/ELK/elasticsearch/templates/elasticsearch.yml.j2
@@ -99,3 +99,9 @@ node.max_local_storage_nodes: {{ elasticsearch_max_local_storage_nodes }}
 #
 action.destructive_requires_name: {{ elasticsearch_destructive_requires_name }}
 
+{% if elasticsearch_disable_bootstrap_syscall_filter %}
+# When using an old kernel
+bootstrap.system_call_filter: false
+{% endif %}
+
+
diff --git a/ELK/elasticsearch/templates/jvm.options.j2 b/ELK/elasticsearch/templates/jvm.options.j2
index 508946d..8caf4fb 100644
--- a/ELK/elasticsearch/templates/jvm.options.j2
+++ b/ELK/elasticsearch/templates/jvm.options.j2
@@ -59,11 +59,20 @@
 # use our provided JNA always versus the system one
 -Djna.nosys=true
 
+# turn off a JDK optimization that throws away stack traces for common
+# exceptions because stack traces are important for debugging
+-XX:-OmitStackTraceInFastThrow
+
 # flag to explicitly tell Netty to not use unsafe
 -Dio.netty.noUnsafe=true
+-Dio.netty.noKeySetOptimization=true
+-Dio.netty.recycler.maxCapacityPerThread=0
 
+-Dlog4j.shutdownHookEnabled=false
 -Dlog4j2.disable.jmx=true
 
+-Djava.io.tmpdir=${ES_TMPDIR}
+
 ## heap dumps
 
 # generate a heap dump when an allocation from the Java heap fails
@@ -95,3 +104,24 @@
 # WARNING: This option will be removed in Elasticsearch 6.0.0 and is provided
 # only for migration purposes.
 #-Delasticsearch.json.allow_unquoted_field_names=true
+# specify an alternative path for heap dumps
+# ensure the directory exists and has sufficient space
+-XX:HeapDumpPath={{ elasticsearch_data_dir }}
+
+## JDK 8 GC logging
+
+8:-XX:+PrintGCDetails
+8:-XX:+PrintGCDateStamps
+8:-XX:+PrintTenuringDistribution
+8:-XX:+PrintGCApplicationStoppedTime
+8:-Xloggc:/var/log/elasticsearch/gc.log
+8:-XX:+UseGCLogFileRotation
+8:-XX:NumberOfGCLogFiles=32
+8:-XX:GCLogFileSize=64m
+
+# JDK 9+ GC logging
+9-:-Xlog:gc*,gc+age=trace,safepoint:file=/var/log/elasticsearch/gc.log:utctime,pid,tags:filecount=32,filesize=64m
+# due to internationalization enhancements in JDK 9 Elasticsearch need to set the provider to COMPAT otherwise
+# time/date parsing will break in an incompatible way for some date patterns and locals
+9-:-Djava.locale.providers=COMPAT
+