centos6.5安装elasticsearch6.3遇到的问题
发现问题背景，有天突然想用ip(非127.0.0.1)，形如192.168.1.16去访问elasticsearch,当我用 crul 192.168.1.16:9201的时候，竟然连不了，后来去官网那看了下文档，说要修改这个参数：network.host
我把这个参数修改成这个值后：network.host: 0.0.0.0，再去启动elasticsearch就报下边这个错误：
[2018-11-14T22:43:15,577][INFO ][o.e.b.BootstrapChecks ] [node-1] bound or publishing to a non-loopback address, enforcing bootstrap checks
ERROR: [4] bootstrap checks failed
[1]: max file descriptors [4096] for elasticsearch process is too low, increase to at least [65536]
[2]: max number of threads [1024] for user [es6] is too low, increase to at least [4096]
[3]: max virtual memory areas vm.max_map_count [65530] is too low, increase to at least [262144]
[4]: system call filters failed to install; check the logs and fix your configuration or disable system call filters at your own risk
bootstrap checks failed 翻译过来就是bootstrap检查失败，就是上边那四个项目失败
1：第一个失败：[1]: max file descriptors [4096] for elasticsearch process is too low, increase to at least [65536]
翻译过来就是：elasticsearch用户拥有的可创建文件描述的权限太低，目前是4096，至少需要65536
解决方法：
切换到root用户修改
vim /etc/security/limits.conf 在最下边加上：
es6 hard nofile 65536
es6 soft nofile 65536
上边的es6是ES的用户
2：第二个失败：[2]: max number of threads [1024] for user [es6] is too low, increase to at least [4096]
翻译过来的意思就是：目前es6这个用户能启动的线程数1024太低了，最少需要4096
解决方法：
vim /etc/security/limits.d/90-nproc.conf ，修改配置如下：
* soft nproc 1024
修改为：
* soft nproc 2048
3：第三个失败：[3]: max virtual memory areas vm.max_map_count [65530] is too low, increase to at least [262144]
翻译过来的意思是：目前最大虚拟内存65530太小了，最少需要262144
解决方法：切换root账户 vim /etc/sysctl.conf
增加一行 vm.max_map_count=262144
接着执行 sysctl -p使其生效:
4：第四个失败：[4]: system call filters failed to install; check the logs and fix your configuration or disable system call filters at your own risk
这是在因为Centos6不支持SecComp，而ES5.2.0以后默认bootstrap.system_call_filter为true进行检测，所以导致检测失败，失败后直接导致ES不能启动。
解决：
在elasticsearch.yml中配置bootstrap.system_call_filter为false，注意要在Memory下面:
#bootstrap.memory_lock: false
bootstrap.system_call_filter: false
然后重启elasticsearch就可以了