Error when installing elasticsearch -can not run elasticsearch as root

The following error occurred when installing elasticsearch:

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

Take a closer look at the error message, which means that it cannot be run as the root user. This is a restriction imposed by elasticsearch for security reasons. To start elasticsearch, you must create a user and use this user to start elasticsearch.

Create user:

adduser elasticsearch

Add a password for this user:

passwd elasticsearch

Give the folder permissions to this user:

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

Switch to this user environment:

su elasticsearch

Started successfully