From 99b91df07971d1a0f8e60f053eb5ae4b824367dd Mon Sep 17 00:00:00 2001
From: Jason Tedor <jason@tedor.me>
Date: Thu, 17 Aug 2017 16:51:02 -0400
Subject: [PATCH] Export HOSTNAME environment variable

We previously explicitly set the HOSTNAME environment variable so that
${HOSTNAME} could be used a placeholder for defining the node.name in
elasticsearch.yml. We removed explicitly setting this because bash
defines HOSTNAME. The problem is that bash defines HOSTNAME as a bash
variable, not as an environment variable. Therefore, to restore the
previous behavior, we export the bash value for HOSTNAME as an
environment variable named HOSTNAME. For consistency between Windows and
the Unix-like systems, we also define HOSTNAME with a value equal to the
environment variable COMPUTERNAME on Windows.

Relates #26262
---
 .../src/main/resources/bin/elasticsearch-env         |  2 ++
 .../src/main/resources/bin/elasticsearch-env.bat     |  2 ++
 .../tests/module_and_plugin_test_cases.bash          | 12 ++++++++++++
 3 files changed, 16 insertions(+)

diff --git a/distribution/src/main/resources/bin/elasticsearch-env b/distribution/src/main/resources/bin/elasticsearch-env
index 83737ae12534b..7e74195e60784 100644
--- a/distribution/src/main/resources/bin/elasticsearch-env
+++ b/distribution/src/main/resources/bin/elasticsearch-env
@@ -65,6 +65,8 @@ fi
 # check the Java version
 "$JAVA" -cp "$ES_CLASSPATH" org.elasticsearch.tools.JavaVersionChecker
 
+export HOSTNAME=$HOSTNAME
+
 ${source.path.env}
 
 if [ -z "$ES_PATH_CONF" ]; then
diff --git a/distribution/src/main/resources/bin/elasticsearch-env.bat b/distribution/src/main/resources/bin/elasticsearch-env.bat
index 5ff573ae08409..626ea3b8c6ff4 100644
--- a/distribution/src/main/resources/bin/elasticsearch-env.bat
+++ b/distribution/src/main/resources/bin/elasticsearch-env.bat
@@ -44,6 +44,8 @@ if not "%JAVA_OPTS%" == "" (
 rem check the Java version
 %JAVA% -cp "%ES_CLASSPATH%" "org.elasticsearch.tools.JavaVersionChecker" || exit /b 1
 
+set HOSTNAME=%COMPUTERNAME%
+
 if "%ES_PATH_CONF%" == "" (
   set ES_PATH_CONF=!ES_HOME!\config
 )
diff --git a/qa/vagrant/src/test/resources/packaging/tests/module_and_plugin_test_cases.bash b/qa/vagrant/src/test/resources/packaging/tests/module_and_plugin_test_cases.bash
index db94bf983d548..91c06974266fa 100644
--- a/qa/vagrant/src/test/resources/packaging/tests/module_and_plugin_test_cases.bash
+++ b/qa/vagrant/src/test/resources/packaging/tests/module_and_plugin_test_cases.bash
@@ -450,3 +450,15 @@ fi
 @test "[$GROUP] test umask" {
     install_jvm_example $(readlink -m jvm-example-*.zip) 0077
 }
+
+@test "[$GROUP] hostname" {
+    local temp=`mktemp -d`
+    cp "$ESCONFIG"/elasticsearch.yml "$temp"
+    echo 'node.name: ${HOSTNAME}' >> "$ESCONFIG"/elasticsearch.yml
+    start_elasticsearch_service
+    wait_for_elasticsearch_status
+    [ "$(curl -XGET localhost:9200/_cat/nodes?h=name)" == "$HOSTNAME" ]
+    stop_elasticsearch_service
+    cp "$temp"/elasticsearch.yml "$ESCONFIG"/elasticsearch.yml
+    rm -rf "$temp"
+}