elasticsearch-5.6.4 无法启动

[es@jdu4e00u53f7 bin]$ ./elasticsearch
OpenJDK 64-Bit Server VM warning: If the number of processors is expected to increase from one, then you should configure the number of parallel GC threads appropriately using -XX:ParallelGCThreads=N
Exception in thread "main" 2017-11-08 23:08:41,993 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.
ElasticsearchParseException[malformed, expected settings to start with 'object', instead was [VALUE_STRING]]
at org.elasticsearch.common.settings.loader.XContentSettingsLoader.load(XContentSettingsLoader.java:73)
at org.elasticsearch.common.settings.loader.XContentSettingsLoader.load(XContentSettingsLoader.java:52)
at org.elasticsearch.common.settings.loader.YamlSettingsLoader.load(YamlSettingsLoader.java:50)
at org.elasticsearch.common.settings.Settings$Builder.loadFromStream(Settings.java:1043)
at org.elasticsearch.common.settings.Settings$Builder.loadFromPath(Settings.java:1032)
at org.elasticsearch.node.InternalSettingsPreparer.prepareEnvironment(InternalSettingsPreparer.java:100)
at org.elasticsearch.cli.EnvironmentAwareCommand.createEnv(EnvironmentAwareCommand.java:75)
at org.elasticsearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:70)
at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:134)
at org.elasticsearch.cli.Command.main(Command.java:90)
at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:91)
at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:84)
[es@jdu4e00u53f7 bin]$