Elasticsearch version: 5.1.1
Plugins installed: 
JVM version: java version "1.8.0_101"
OS version: CentOS release 6.8 (Final)
Description of the problem including expected versus actual behavior:
Elastic search is not starting. It gives me warning "org.elasticsearch.bootstrap.StartupException: java.lang.RuntimeException: can not run elasticsearch as root". But when I run without root, it gives me long list of errors; some of them are "java.io.FileNotFoundException: permission denied."
Steps to reproduce:
I have lowered the memory limits from config/jvm.options to 100-200mb. But doesn't work.
Provide logs (if relevant):
Describe the feature:
Any help is appreciated. Thanks in advance!