报错如下
[root@iz2zeedts96uaocqhzt5ddz elasticsearch]# ./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

[2018-07-09T10:32:40,579][WARN ][o.e.b.ElasticsearchUncaughtExceptionHandler] [] uncaught exception in thread [main]

org.elasticsearch.bootstrap.StartupException: java.lang.RuntimeException: can not run elasticsearch as root

at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:140) ~[elasticsearch-6.3.1.jar:6.3.1]

at org.elasticsearch.bootstrap.Elasticsearch.execute(Elasticsearch.java:127) ~[elasticsearch-6.3.1.jar:6.3.1]

at org.elasticsearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:86) ~[elasticsearch-6.3.1.jar:6.3.1]

at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:124) ~[elasticsearch-cli-6.3.1.jar:6.3.1]

at org.elasticsearch.cli.Command.main(Command.java:90) ~[elasticsearch-cli-6.3.1.jar:6.3.1]

at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:93) ~[elasticsearch-6.3.1.jar:6.3.1]

at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:86) ~[elasticsearch-6.3.1.jar:6.3.1]

Caused by: java.lang.RuntimeException: can not run elasticsearch as root

at org.elasticsearch.bootstrap.Bootstrap.initializeNatives(Bootstrap.java:104) ~[elasticsearch-6.3.1.jar:6.3.1]

at org.elasticsearch.bootstrap.Bootstrap.setup(Bootstrap.java:171) ~[elasticsearch-6.3.1.jar:6.3.1]

at org.elasticsearch.bootstrap.Bootstrap.init(Bootstrap.java:326) ~[elasticsearch-6.3.1.jar:6.3.1]

at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:136) ~[elasticsearch-6.3.1.jar:6.3.1]

... 6 more