在安装elasticsearch的时候，很多人安装完成启动之后可能都会报bootstrap checks failed的错误，其中可能有如下几种类型：
[1]: max file descriptors [1024] 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]
[3]: system call filters failed to install; check the logs and fix your configuration or disable system call filters at your own risk
[4]: max number of threads [1024] for user [lish] likely too low, increase to at least [2048]
针对第一个问题：max file descriptors [1024] for elasticsearch process is too low, increase to at least [4029]
编辑 /etc/security/limits.conf，追加以下内容；
* soft nofile 65536 #具体的值可以按照错误提示中方括号"[ ]"中，提示的值修改
* hard nofile 65536
注：如果编辑重启启动之后还不能消除这个错误，则重登陆用户。
针对第二个问题：max virtual memory areas vm.max_map_count [65530] is too low, increase to at least [262144]
编辑 /etc/sysctl.conf，追加以下内容：
vm.max_map_count=262144
保存后，执行：
sysctl -p
重新启动，成功。
针对第三个问题：system call filters failed to install; check the logs and fix your configuration or disable system call filters at your own risk
出现错误的原因：是因为centos6.x操作系统不支持SecComp，而elasticsearch 5.5.2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。
在elasticsearch.yml中添加配置项：bootstrap.system_call_filter为false：
bootstrap.memory_lock: false
bootstrap.system_call_filter: false
针对第四个问题：max number of threads [1024] for user [wh] likely too low, increase to at least [2048]
vi /etc/security/limits.d/90-nproc.conf
修改如下内容：
* soft nproc 1024
#修改为
* soft nproc 2048
注：以上问题如果编辑重启启动之后还不能消除这个错误，则重登陆用户。