转载：https://my.oschina.net/u/2510243/blog/810520
max file descriptors [4096] for elasticsearch process is too low, increase to at least [65536]
max number of threads [1024] for user [hadoop] is too low, increase to at least [2048]
max virtual memory areas vm.max_map_count [65530] is too low, increase to at least [262144]
解决方案：
max file descriptors [4096] for elasticsearch process is too low, increase to at least [65536]
切换到root用户
ulimit -Hn 查看硬限制
vim /etc/security/limits.conf
添加下面设置 hadoop是用户
hadoop soft nofile 65536
hadoop hard nofile 65536
退出用户重新登录，使配置生效
重新 ulimit -Hn 查看硬限制 会发现数值有4096改成65535
vim /etc/security/limits.d/90-nproc.conf
找到如下内容：
soft nproc 1024
修改为
soft nproc 2048
vi /etc/sysctl.conf
添加下面配置：
vm.max_map_count=655360
并执行命令：
sysctl -p