3. [2018-01-17T17:52:58,753][WARN ][o.e.b.ElasticsearchUncaughtExceptionHandler] [cms-node1] uncaught exception in thread [main]
    4. org.elasticsearch.bootstrap.StartupException: java.lang.RuntimeException: can not run elasticsearch as root
    5.        at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:125) ~[elasticsearch-6.1.2.jar:6.1.2]
    6.        at org.elasticsearch.bootstrap.Elasticsearch.execute(Elasticsearch.java:112) ~[elasticsearch-6.1.2.jar:6.1.2]
    7.        at org.elasticsearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:86) ~[elasticsearch-6.1.2.jar:6.1.2]
    8.        at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:124) ~[elasticsearch-cli-6.1.2.jar:6.1.2]
    9.        at org.elasticsearch.cli.Command.main(Command.java:90) ~[elasticsearch-cli-6.1.2.jar:6.1.2]
    10.        at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:92) ~[elasticsearch-6.1.2.jar:6.1.2]
    11.        at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:85) ~[elasticsearch-6.1.2.jar:6.1.2]
    12. Caused by: java.lang.RuntimeException: can not run elasticsearch as root
    13.        at org.elasticsearch.bootstrap.Bootstrap.initializeNatives(Bootstrap.java:104) ~[elasticsearch-6.1.2.jar:6.1.2]
    14.        at org.elasticsearch.bootstrap.Bootstrap.setup(Bootstrap.java:171) ~[elasticsearch-6.1.2.jar:6.1.2]
    15.        at org.elasticsearch.bootstrap.Bootstrap.init(Bootstrap.java:322) ~[elasticsearch-6.1.2.jar:6.1.2]
    16.        at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:121) ~[elasticsearch-6.1.2.jar:6.1.2]
    17.        ... 6 more
    19. 解决方案：
    21. 因为安全问题elasticsearch 不让用root用户直接运行，所以要创建新用户
    23. 建议创建一个单独的用户用来运行ElasticSearch
    25. 创建elsearch用户组及elsearch用户
    27. groupadd elsearch
    28. useradd elsearch -g elsearch -p elsearch