Elasticsearch5.x版本以上非root账户启动

配置完成后，即可以启动Elasticsearch，但是在启动之前需要先创建一个用户，并将此用户的权限赋予Elasticsearch的目录。（主要是因为Elasticsearch不能用root用户来启动，必须用非root用户）

[root@localhost /]# useradd elkuser
#elasticsearch 只能用非 root 启动
[root@localhost /]#  chown -R elkuser.elkuser elasticsearch-6.1.0

[root@localhost elasticsearch-6.1.0]# pwd
/usr/local/elasticsearch-6.1.0
[root@localhost elasticsearch-6.1.0]# cd bin
[root@localhost bin]# ls
elasticsearch      elasticsearch-env.bat       elasticsearch-plugin       elasticsearch-service-mgr.exe  elasticsearch-translog.bat
elasticsearch.bat  elasticsearch-keystore      elasticsearch-plugin.bat   elasticsearch-service-x64.exe
elasticsearch-env  elasticsearch-keystore.bat  elasticsearch-service.bat  elasticsearch-translog
[root@localhost bin]# ./elasticsearch

Elasticsearch文件打开数及堆大小检测

在ES启动过程中可能会报如下的错误：

ERROR: [2] bootstrap checks failed
[1]: max file descriptors [4096] for elasticsearch process is too low, increase to at least [65536]
[2]: max virtual memory areas vm.max_map_count [65530] is too low, increase to at least [262144]

错误主要说明，linux中elasticsearch最大文件打开数太小，需要我们修改到对应的数值：

1.max file descriptors [4096] for elasticsearch process is too low, increase to at least [65536]

修改/etc/security/limits.conf文件，添加或修改如下行：
*        hard    nofile           65536
*        soft    nofile           65536

2.max virtual memory areas vm.max……

修改 /etc/sysctl.conf 文件,添加如下行：

vm.max_map_count=262144
修改好了以后，运行/sbin/sysctl -p

重启以后，再启动es即可，就可以通过主机ip访问。

如果是内存不足就需要调整内存大小了或者调整config/jvm.options的参数

在elasticsearch-6.1.0/config目录中有jvm.options文件，可以设置JVM大小
[root@localhost config]# pwd
/usr/local/elasticsearch-6.1.0/config
[root@localhost config]# ls
elasticsearch.yml  jvm.options  log4j2.properties
[root@localhost config]# vi jvm.options
-Xms2g
-Xmx2g

启动Elasticsearch

前序工作全部准备完成后，即可在elasticsearch-6.1.0目录中的bin目录下执行elasticsearch-6.1.0文件：

[root@localhost elasticsearch-6.1.0]# pwd
/usr/local/elasticsearch-6.1.0
[root@localhost elasticsearch-6.1.0]# cd bin
[root@localhost bin]# ls
elasticsearch      elasticsearch-env.bat       elasticsearch-plugin       elasticsearch-service-mgr.exe  elasticsearch-translog.bat
elasticsearch.bat  elasticsearch-keystore      elasticsearch-plugin.bat   elasticsearch-service-x64.exe
elasticsearch-env  elasticsearch-keystore.bat  elasticsearch-service.bat  elasticsearch-translog
[root@localhost bin]# ./elasticsearch
[root@localhost bin]# ./elasticsearch -d 可以使其在后台运行