centos7 修改 ulimit参数

    Each line describes a limit for a user in the form:
   
                       
     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
     
	 can have the two values:
         - "soft" for enforcing the soft limits
         - "hard" for enforcing hard limits
 
	 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

1. vi /etc/security/limit.conf添加以下内容

      # open files  (-n)
      * soft nofile 65536
      * hard nofile 65536
      
      # max user processes   (-u)
      * soft nproc 65565
      * hard nproc 65565

2. 退出登录重新连接查看参数配置

 ulimit -a

3. 如果某一项没有生效，在/etc/security/limits.d下的文件里设置，此文件中的配置会覆盖1中的文件，例如

*          soft    nproc     65565

4. 退出登录重新连接查看参数配置

 ulimit -a