在centos6安装ES的时候遇到不少问题。这里记录日志。以后安装一定要升级centos7，别说啥稳定问题了，该升级就升级。
[1]: max file descriptors [4096] for elasticsearch process is too low, increase to at least [65536]
[2]: max number of threads [1024] for user [es] is too low, increase to at least [2048]
[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
解决方案：
vim config/elasticsearch.yml
追加
bootstrap.memory_lock: false
bootstrap.system_call_filter: false
vi /etc/security/limits.conf
追加
* soft nofile 65536
* hard nofile 131072
* soft nproc 2048
* hard nproc 4096
vi /etc/security/limits.d/90-nproc.conf
追加
修改如下内容：
* soft nproc 1024
#修改为
* soft nproc 2048
vi /etc/sysctl.conf
追加
vm.max_map_count=655360
sysctl -p