About the nproc restrictions of ulimit in rhel6

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• Change the number of processes that a user can open in the Current Shell
• Modify the limits. conf configuration file to take effect.

Change the number of processes that a user can open in the Current Shell

Modify the limits. conf configuration file to take effect.

2. [Root @ Kumu ~] #Ulimit-// View the global coefficient of the current configuration file ulimit
4. Core File size (blocks,-C) 0
6. Data seg size (Kbytes,-d) Unlimited
8. Scheduling Priority (-e) 0
10. File size (blocks,-f) Unlimited
12. Pending signals (-I) 1829
14. Max locked memory (Kbytes,-l) 64
16. Max memory size (Kbytes,-m) Unlimited
18. Open File (-N) 1024
20. Pipe size (512 bytes,-p) 8
22. POSIX message queues (bytes,-q) 819200
24. Real-time priority (-R) 0
26. Stack size (Kbytes,-S) 10240
28. CPU time (seconds,-T) Unlimited
30. Max user processes (-u) 1024
32. Virtual Memory (Kbytes,-v) Unlimited
34. File locks (-x) Unlimited
36. [Root @ Kumu ~] #Vim/etc/security/limits. conf 
38. [Root @ Kumu ~] #Grep '^ *'/etc/security/limits. conf
40. * Soft nproc 10240
42. * Hard nproc 10240
44. * Soft nofile 10240
46. * Hard nofile 10240
48. [Root @ Kumu ~] #

 

Log out of the current user and log on again to make the modified limits take effect.

1. [Root @ Kumu ~] #Ulimit-n
2. 10240
3. [Root @ Kumu ~] #Ulimit-u// It is found that nproc has not changed like nofile
4. 1024
5. [Root @ Kumu ~] #

 

According to Google search, the configuration file is introduced in rhel6./Etc/security/limits. d/90-nproc.conf

(See @ Yang Devin's article redhat5 and redhat6 for different ulimits root users)

1. [Root @ Kumu ~] # Cat/etc/security/limits. d/90-nproc.conf
2. # Default limit for number of user's processes to prevent
3. # Accidental fork bombs.
4. # See rhbz #432903 for reasoning.
5.  
6. * Soft nproc 1024
7. [Root @ Kumu ~] #

 

Modify the file to see if it is affected.

1. [Root @ Kumu ~] # Vim/etc/security/limits. d/90-nproc.conf
2. [Root @ Kumu ~] # Cat/etc/security/limits. d/90-nproc.conf
3. # Default limit for number of user's processes to prevent
4. # Accidental fork bombs.
5. # See rhbz #432903 for reasoning.
6.  
7. # * Soft nproc 1024
8. * Soft nproc 65535
9. [Root @ Kumu ~] #

Log out of the current user and log on again to make the modified limits take effect. Run the following command to check that the modification is successful.

1. [Root @ Kumu ~] # Ulimit-u
2. 10240
3. [Root @ Kumu ~] # Ulimit-n
4. 10240
5. [Root @ Kumu ~] #

 

Therefore, if you want to modify the nproc limit in the configuration file limits. conf/Etc/security/limits. d/90-nproc.confNproc value size inBut the shell terminal is not restricted.

In addition, I guess that if the * number is used to make global users take effectNproc value in/etc/security/limits. d/90-nproc.confBut if it is only for a user, it is not affected by the nproc value of the file.

2. [Root @ Kumu ~] # Vim/etc/security/limits. d/90-nproc.conf // restore system default settings
4. [Root @ Kumu ~] # Cat/etc/security/limits. d/90-nproc.conf
6. # Default limit for number of user's processes to prevent
8. # Accidental fork bombs.
10. # See rhbz #432903 for reasoning.
12.  
14. * Soft nproc 1024
16. # * Soft nproc 65535
18. [Root @ Kumu ~] # Vim/etc/security/limits. conf // test only for a user (root is used here)
20. [Root @ Kumu ~] # Grep '^ root'/etc/security/limits. conf
22. Root soft nproc 10240
24. Root hard nproc 10240
26. [Root @ Kumu ~] #

 

Log out of the current user and log on again to make the modified limits take effect. Run the following command to check that the modification is successful.

1. [Root @ Kumu ~] # Ulimit-u
2. 10240
3. [Root @ Kumu ~] # Ulimit-n
4. 10240
5. [Root @ Kumu ~] #

I previously guessed it is correct, that is, only when the * number is used for global users to take effect, the value of the nproc that takes effect is the file size./Etc/security/limits. d/90-nproc.confMediumNprocValue sizeBut if it is only for a user, it is not affected by the nproc value of the file.