安装elasticsearch报错-can not run elasticsearch as root

安装elasticsearch出现如下错误：

Java HotSpot(TM) 64-Bit Server VM warning: Option UseConcMarkSweepGC was deprecated in version 9.0 and will likely be removed in a future release.
[2020-05-20T22:03:39,568][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:127) ~[elasticsearch-5.5.1.jar:5.5.1]
	at org.elasticsearch.bootstrap.Elasticsearch.execute(Elasticsearch.java:114) ~[elasticsearch-5.5.1.jar:5.5.1]
	at org.elasticsearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:67) ~[elasticsearch-5.5.1.jar:5.5.1]
	at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:122) ~[elasticsearch-5.5.1.jar:5.5.1]
	at org.elasticsearch.cli.Command.main(Command.java:88) ~[elasticsearch-5.5.1.jar:5.5.1]
	at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:91) ~[elasticsearch-5.5.1.jar:5.5.1]
	at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:84) ~[elasticsearch-5.5.1.jar:5.5.1]
Caused by: java.lang.RuntimeException: can not run elasticsearch as root
	at org.elasticsearch.bootstrap.Bootstrap.initializeNatives(Bootstrap.java:106) ~[elasticsearch-5.5.1.jar:5.5.1]
	at org.elasticsearch.bootstrap.Bootstrap.setup(Bootstrap.java:194) ~[elasticsearch-5.5.1.jar:5.5.1]
	at org.elasticsearch.bootstrap.Bootstrap.init(Bootstrap.java:351) ~[elasticsearch-5.5.1.jar:5.5.1]
	at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:123) ~[elasticsearch-5.5.1.jar:5.5.1]
	... 6 more

仔细看一下报错信息，就是说不能用root用户运行，这是elasticsearch出于安全考虑做出的限制，那么要启动elasticsearch就要用创建一个用户使用该用户来启动elasticsearch。

创建用户：

adduser elasticsearch

为该用户添加密码：

passwd elasticsearch

把文件夹的权限给这个用户：

chown -R elasticsearch /usr/local/elasticSearch/elasticsearch-5.5.1

切换到这个用户环境下：

su elasticsearch

启动成功