关于RHEL6中ulimit的nproc限制

拼搏现实的明天。 2022-05-08 12:24 161阅读 0赞

### 当前shell下更改用户可打开进程数 ###

![1355643978_6529.png][]

### 修改limits.conf配置文件生效 ###

\[root@kumu ~\]\# **ulimit -a** //查看当前配置文件ulimit全局系数

core file size  (blocks, -c) 0

data seg size  (kbytes, -d) unlimited

scheduling priority (-e) 0

file size  (blocks, -f) unlimited

pending signals (-i) 1829

max locked memory  (kbytes, -l) 64

max memory size  (kbytes, -m) unlimited

open files (-n) 1024

pipe size  (512 bytes, -p) 8

POSIX message queues  (bytes, -q) 819200

real-time priority (-r) 0

stack size  (kbytes, -s) 10240

cpu time  (seconds, -t) unlimited

max user processes (-u) 1024

virtual memory  (kbytes, -v) unlimited

file locks (-x) unlimited

\[root@kumu ~\]\# **vim /etc/security/limits.conf**

\[root@kumu ~\]\# **grep '^\*' /etc/security/limits.conf**

\* soft nproc 10240

\* hard nproc 10240

\* soft nofile 10240

\* hard nofile 10240

\[root@kumu ~\]\#

退出当前用户，重新登录即可让之前修改的limits生效

\[root@kumu ~\]\# **ulimit -n**

10240

\[root@kumu ~\]\# **ulimit -u** //发现nproc并没有像nofile一样而改变

1024

\[root@kumu ~\]\#

经google搜索获知，RHEL6下引入了配置文件**/etc/security/limits.d/90-nproc.conf**

（参见了@杨德华Devin 文章[redhat5和redhat6 root用户不同的ulimits][redhat5_redhat6 root_ulimits]）

\[root@kumu ~\]\# **cat /etc/security/limits.d/90-nproc.conf**

\# Default limit for number of user'sprocesses to prevent

\# accidental fork bombs.

\# See rhbz \#432903 for reasoning.

\* soft nproc  **1024**

\[root@kumu ~\]\#

我们修改这个文件尝试是否因为该文件影响，修改如下

\[root@kumu ~\]\# **vim /etc/security/limits.d/90-nproc.conf**

\[root@kumu ~\]\# **cat /etc/security/limits.d/90-nproc.conf**

\# Default limit for number of user'sprocesses to prevent

\# accidental fork bombs.

\# See rhbz \#432903 for reasoning.

\#\* soft nproc 1024

\* soft nproc **65535**

\[root@kumu ~\]\#

退出当前用户，重新登录即可让之前修改的limits生效，执行如下命令发现修改成功

\[root@kumu ~\]\# **ulimit -u**

10240

\[root@kumu ~\]\# **ulimit -n**

10240

\[root@kumu ~\]\#

由此可知，如果要修改配置文件limits.conf中的nproc限制上限是受文件**/etc/security/limits.d/90-nproc.conf中nproc值大小**制约的，但是shell终端下是不受制约的

另外笔者猜想，如果使用\*号让全局用户生效是受文件**/etc/security/limits.d/90-nproc.conf中nproc值大小**制约的，而如果仅仅是针对某个用户，那么就不受该文件nproc值大小的影响

\[root@kumu ~\]\# **vim /etc/security/limits.d/90-nproc.conf**//恢复系统默认设置

\[root@kumu ~\]\# **cat /etc/security/limits.d/90-nproc.conf**

\# Default limit for number of user'sprocesses to prevent

\# accidental fork bombs.

\# See rhbz \#432903 for reasoning.

\* soft nproc **1024**

\#\* soft nproc 65535

\[root@kumu ~\]\# **vim /etc/security/limits.conf** //只针对某个用户测试（这里使用root）

\[root@kumu ~\]\# **grep '^root' /etc/security/limits.conf**

root soft nproc 10240

root hard nproc 10240

\[root@kumu ~\]\#

退出当前用户，重新登录即可让之前修改的limits生效，执行如下命令发现修改成功

\[root@kumu ~\]\# **ulimit -u**

10240

\[root@kumu ~\]\# **ulimit -n**

10240

\[root@kumu ~\]\#

笔者之前猜想正确，即只有当使用\*号让全局用户生效的时候，生效的nproc的值大小是受文件**/etc/security/limits.d/90-nproc.conf中nproc值大小**制约的，而如果仅仅是针对某个用户，那么就不受该文件nproc值大小的影响。本文链接：[关于RHEL6中ulimit的nproc限制][RHEL6_ulimit_nproc]

[1355643978_6529.png]: https://img-my.csdn.net/uploads/201212/16/1355643978_6529.png
[redhat5_redhat6 root_ulimits]: http://dbahacker.com/linux/redhat5-%E5%92%8Credhat6-root%E7%94%A8%E6%88%B7%E4%B8%8D%E5%90%8C%E7%9A%84ulimits/comment-page-1#comment-6009
[RHEL6_ulimit_nproc]: http://blog.csdn.net/kumu_linux/article/details/8301760