安装配置Elasticsearch5.4.1的时候遇到的一些问题，通过查找资料解决。整理记录一下，便于以后遇到同样的问题能够快速解决。
Elasticsearch安装好后，默认只允许通过127.0.0.1访问，如果我们希望在另外一台机器上访问Elasticsearch的话，需要修改主机配置：
#network.host: 192.168.0.1 networ.host: 192.168.5.82 <--修改为本机iP，或者0.0.0.0
保存退出后，重新启动Elasticsearch的话会报错，无法启动。报错如下：
[WARN ][o.e.b.JNANatives ] unable to install syscall filter: java.lang.UnsupportedOperationException: seccomp unavailable: requires kernel 3.5+ with CONFIG_SECCOMP and CONFIG_SECCOMP_FILTER compiled in 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 [elsearch] 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
WARN:只是一个警告，使用新版本的linux就没事了。
错误一：max file descriptors [4096] for elasticsearch process is too low, increase to at least [65536]
修改/etc/security/limits.conf配置文件，添加如下内容：
# vim /etc/security/limits.conf * soft nofile 65536 * hard nofile 131072 * soft nproc 2048 * hard nproc 4096
错误二：max number of threads [1024] for user [elsearch] is too low, increase to at least [2048]
修改/etc/security/limits.d/90-nproc.conf配置文件，修改内容如下：
# vim /etc/security/limits.d/90-nproc.conf * soft nproc 1024 #修改为 * soft nproc 2048
错误三：max virtual memory areas vm.max_map_count [65530] is too low, increase to at least [262144]
修改配置文件/etc/sysctl.conf，修改内容如下：
# vim /etc/sysctl.conf 添加下面配置： vm.max_map_count = 655360
错误四：system call filters failed to install; check the logs and fix your configuration or disable system call filters at your own risk原因：
这是在因为操作系统不支持SecComp，而ES5.4.1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
修改好后重启ES，能够正常启动。