[杂七杂八] can not run elasticsearch as root at org.elasticsearch.boots

安装elasticsearch的时候运行./elasticsearch报错
解决办法参考：CENTOS安装ElasticSearch https://my.oschina.net/topeagle/blog/591451

[root@ELK bin]# ./elasticsearchOpenJDK 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[2017-05-25T05:21:54,647][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-5.4.0.jar:5.4.0]    at org.elasticsearch.bootstrap.Elasticsearch.execute(Elasticsearch.java:114) ~[elasticsearch-5.4.0.jar:5.4.0]    at org.elasticsearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:67) ~[elasticsearch-5.4.0.jar:5.4.0]    at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:122) ~[elasticsearch-5.4.0.jar:5.4.0]    at org.elasticsearch.cli.Command.main(Command.java:88) ~[elasticsearch-5.4.0.jar:5.4.0]    at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:91) ~[elasticsearch-5.4.0.jar:5.4.0]    at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:84) ~[elasticsearch-5.4.0.jar:5.4.0]Caused by: java.lang.RuntimeException: can not run elasticsearch as root    at org.elasticsearch.bootstrap.Bootstrap.initializeNatives(Bootstrap.java:106) ~[elasticsearch-5.4.0.jar:5.4.0]    at org.elasticsearch.bootstrap.Bootstrap.setup(Bootstrap.java:204) ~[elasticsearch-5.4.0.jar:5.4.0]    at org.elasticsearch.bootstrap.Bootstrap.init(Bootstrap.java:360) ~[elasticsearch-5.4.0.jar:5.4.0]    at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:123) ~[elasticsearch-5.4.0.jar:5.4.0]    ... 6 more

提示报错：java.lang.RuntimeException: can not run elasticsearch as root
将elasticsearch所在的文件夹所属用户和组都改为admin，切换到admin再启动

• 创建elsearch用户组及elsearch用户

cd /usr/localchown -R admin:admin elasticsearch

切换到admin用户再运行

[admin@ELK bin]$ ./elasticsearchOpenJDK 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[2017-05-25T05:25:38,824][INFO ][o.e.n.Node               ] [] initializing ...[2017-05-25T05:25:38,989][INFO ][o.e.e.NodeEnvironment    ] [cUN3nln] using [1] data paths, mounts [[/ (rootfs)]], net usable_space [23.1gb], net total_space [27.7gb], spins? [unknown], types [rootfs][2017-05-25T05:25:38,989][INFO ][o.e.e.NodeEnvironment    ] [cUN3nln] heap size [1.9gb], compressed ordinary object pointers [true][2017-05-25T05:25:38,991][INFO ][o.e.n.Node               ] node name [cUN3nln] derived from node ID [cUN3nlnKQAmkk-YEP-v9uQ]; set [node.name] to override[2017-05-25T05:25:38,992][INFO ][o.e.n.Node               ] version[5.4.0], pid[19619], build[780f8c4/2017-04-28T17:43:27.229Z], OS[Linux/3.10.0-514.el7.x86_64/amd64], JVM[Oracle Corporation/OpenJDK 64-Bit Server VM/1.8.0_131/25.131-b11][2017-05-25T05:25:41,049][INFO ][o.e.p.PluginsService     ] [cUN3nln] loaded module [aggs-matrix-stats][2017-05-25T05:25:41,049][INFO ][o.e.p.PluginsService     ] [cUN3nln] loaded module [ingest-common][2017-05-25T05:25:41,049][INFO ][o.e.p.PluginsService     ] [cUN3nln] loaded module [lang-expression][2017-05-25T05:25:41,049][INFO ][o.e.p.PluginsService     ] [cUN3nln] loaded module [lang-groovy][2017-05-25T05:25:41,049][INFO ][o.e.p.PluginsService     ] [cUN3nln] loaded module [lang-mustache][2017-05-25T05:25:41,050][INFO ][o.e.p.PluginsService     ] [cUN3nln] loaded module [lang-painless][2017-05-25T05:25:41,050][INFO ][o.e.p.PluginsService     ] [cUN3nln] loaded module [percolator][2017-05-25T05:25:41,050][INFO ][o.e.p.PluginsService     ] [cUN3nln] loaded module [reindex][2017-05-25T05:25:41,050][INFO ][o.e.p.PluginsService     ] [cUN3nln] loaded module [transport-netty3][2017-05-25T05:25:41,050][INFO ][o.e.p.PluginsService     ] [cUN3nln] loaded module [transport-netty4][2017-05-25T05:25:41,051][INFO ][o.e.p.PluginsService     ] [cUN3nln] no plugins loaded[2017-05-25T05:25:44,144][INFO ][o.e.d.DiscoveryModule    ] [cUN3nln] using discovery type [zen][2017-05-25T05:25:45,204][INFO ][o.e.n.Node               ] initialized[2017-05-25T05:25:45,204][INFO ][o.e.n.Node               ] [cUN3nln] starting ...[2017-05-25T05:25:45,501][INFO ][o.e.t.TransportService   ] [cUN3nln] publish_address {127.0.0.1:9300}, bound_addresses {[::1]:9300}, {127.0.0.1:9300}