ElasticSearch服務器運行環境設置

操作目的：實現ElasticSearch在Centos服務器中運行

操作環境：ElasticSearch 7.5、Centos 7

操作步驟：

1. 修改/etc/security/limits.conf文件

   # /etc/security/limits.conf
   #
   #This file sets the resource limits for the users logged in via PAM.
   #It does not affect resource limits of the system services.
   #
   #Also note that configuration files in /etc/security/limits.d directory,
   #which are read in alphabetical order, override the settings in this
   #file in case the domain is the same or more specific.
   #That means for example that setting a limit for wildcard domain here
   #can be overriden with a wildcard setting in a config file in the
   #subdirectory, but a user specific setting here can be overriden only
   #with a user specific setting in the subdirectory.
   #
   #Each line describes a limit for a user in the form:
   #
   #<domain>        <type>  <item>  <value>
   #
   #Where:
   #<domain> can be:
   #        - a user name
   #        - a group name, with @group syntax
   #        - the wildcard *, for default entry
   #        - the wildcard %, can be also used with %group syntax,
   #                 for maxlogin limit
   #
   #<type> can have the two values:
   #        - "soft" for enforcing the soft limits
   #        - "hard" for enforcing hard limits
   #
   #<item> can be one of the following:
   #        - core - limits the core file size (KB)
   #        - data - max data size (KB)
   #        - fsize - maximum filesize (KB)
   #        - memlock - max locked-in-memory address space (KB)
   #        - nofile - max number of open file descriptors
   #        - rss - max resident set size (KB)
   #        - stack - max stack size (KB)
   #        - cpu - max CPU time (MIN)
   #        - nproc - max number of processes
   #        - as - address space limit (KB)
   #        - maxlogins - max number of logins for this user
   #        - maxsyslogins - max number of logins on the system
   #        - priority - the priority to run user process with
   #        - locks - max number of file locks the user can hold
   #        - sigpending - max number of pending signals
   #        - msgqueue - max memory used by POSIX message queues (bytes)
   #        - nice - max nice priority allowed to raise to values: [-20, 19]
   #        - rtprio - max realtime priority
   #
   #<domain>      <type>  <item>         <value>
   #
   
   #*               soft    core            0
   #*               hard    rss             10000
   #@student        hard    nproc           20
   #@faculty        soft    nproc           20
   #@faculty        hard    nproc           50
   #ftp             hard    nproc           0
   #@student        -       maxlogins       4
   * hard nofile 65536
   * soft nofile 131072
   * hard nproc 4096
   * soft nproc 2048
   # End of file
   

   nofile - 打開文件的最大數目

   noproc - 進程的最大數目

   soft 指的是當前系統生效的設置值

   hard 表明系統中所能設定的最大值

2. 修改/etc/sysctl.conf

   # sysctl settings are defined through files in
   # /usr/lib/sysctl.d/, /run/sysctl.d/, and /etc/sysctl.d/.
   #
   # Vendors settings live in /usr/lib/sysctl.d/.
   # To override a whole file, create a new file with the same in
   # /etc/sysctl.d/ and put new settings there. To override
   # only specific settings, add a file with a lexically later
   # name in /etc/sysctl.d/ and put new settings there.
   #
   # For more information, see sysctl.conf(5) and sysctl.d(5).
   
   vm.max_map_count=655360
   fs.file-max=655360
   

   vm.max_map_count=65530，因此缺省配置下，單個jvm能開啓的最大線程數爲其一半

   file-max是設置 系統所有進程一共可以打開的文件數量