I am trying to install Elastic Search in Ubuntu 16.04.5 LTS but getting following errors. Please help.

root@vmawinkatti:/opt/elasticsearch-6.3.2/logs# /opt/elasticsearch-6.3.2/bin/elasticsearch
warning: ignoring JAVA_OPTS=-Djava.io.tmpdir=/tmp; pass JVM parameters via ES_JAVA_OPTS
Exception in thread "main" 2018-08-10 22:26:53,454 main ERROR No log4j2 configuration file found. Using default configuration: logging only errors to the console. Set system property 'log4j2.debug' to show Log4j2 internal initialization logging.
SettingsException[Failed to load settings from [elasticsearch.yml]]; nested: ParsingException[Failed to parse object: expecting token of type [START_OBJECT] but found [VALUE_STRING]];
at org.elasticsearch.common.settings.Settings$Builder.loadFromStream(Settings.java:1192)
at org.elasticsearch.common.settings.Settings$Builder.loadFromPath(Settings.java:1165)
at org.elasticsearch.node.InternalSettingsPreparer.prepareEnvironment(InternalSettingsPreparer.java:100)
at org.elasticsearch.cli.EnvironmentAwareCommand.createEnv(EnvironmentAwareCommand.java:95)
at org.elasticsearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:86)
at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:124)
at org.elasticsearch.cli.Command.main(Command.java:90)
at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:93)
at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:86)
Caused by: ParsingException[Failed to parse object: expecting token of type [START_OBJECT] but found [VALUE_STRING]]
at org.elasticsearch.common.xcontent.XContentParserUtils.ensureExpectedToken(XContentParserUtils.java:78)
at org.elasticsearch.common.settings.Settings.fromXContent(Settings.java:672)
at org.elasticsearch.common.settings.Settings.access$500(Settings.java:84)
at org.elasticsearch.common.settings.Settings$Builder.loadFromStream(Settings.java:1188)
... 8 more

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