elasticsearch5.x安装中一些问题的解决办法

1.root超级用户不能正常启动

由于elasticsearch2.0版本以后不能使用root来启动，所以需要创建一个普通用户来启动。

[root@bogon ~]# groupadd elasticsearch
[root@bogon ~]# useradd elasticsearch -g elasticsearch
[root@bogon ~]# chown -R elasticsearch.elasticsearch /usr/local/elk/elasticsearch-5.2.
[root@bogon ~]# su - elasticsearch
[elasticsearch@bogon ~]$ cd /usr/local/elk/elasticsearch-5.2./bin/
[elasticsearch@bogon bin]$ ./elasticsearch

由普通用户来启动，则可以正常启动服务。

2.ERROR: bootstrap checks failed

max file descriptors [4096] for elasticsearch process likely too low, increase to at least [65536]
max number of threads [1024] for user [lishang] likely too low, increase to at least [2048]

解决：切换到root用户，编辑limits.conf 添加类似如下内容

vi /etc/security/limits.conf 

添加如下内容:

* soft nofile 65536

* hard nofile 131072

* soft nproc 2048

* hard nproc 4096

3.max number of threads [1024] for user [lish] likely too low, increase to at least [2048]

解决：切换到root用户，进入limits.d目录下修改配置文件。

vi /etc/security/limits.d/90-nproc.conf 

修改如下内容：

* soft nproc 1024

#修改为

* soft nproc 2048

4.max virtual memory areas vm.max_map_count [65530] likely too low, increase to at least [262144]

解决：切换到root用户修改配置sysctl.conf

vi /etc/sysctl.conf 

添加下面配置：

vm.max_map_count=655360

并执行命令：

sysctl -p

然后，重新启动elasticsearch，即可启动成功。