6.2 Lab - Not seeing any difference after changing kernel.pid_max

Comments

• coop Posts: 283

  May 2015

  On some systems (which I haven't seen for a long time) you have to do
  systctl -w pid_max=12000
  or whatever, where the -w is for write. What distro is this?
  I think technically the -w is required but ignored by most installations.
  Read the man page for sysctl
  

  0
• adamherst Posts: 25

  May 2015

  Hi ultraninja,
  
  I think the reason you didn't see any difference after changing pid_max is because you didn't change it to a value less than the PID of your first cat process. That is, you changed pid_max to 10000 but the PID of the first cat process was 2127. If you had changed pid_max to 2000, I think you would then see the PIDs roll over to 300 again.
  
  Thanks,
  
  Adam
  

  0
• ultraninja Posts: 20

  May 2015

  Thanks for that tip Adam. It worked perfectly. Though I set pid_max to 10000 again, it was lower than the pid of cat so the next cat started at 378. Excellent! How are you enjoying the course?
  

  
  [[email protected] ~]$ sudo sysctl kernel.pid_max
  [sudo] password for sfox: 
  kernel.pid_max = 32768
  [[email protected] ~]$ cat &
  [1] 20081
  
  [1]+  Stopped                 cat
  [[email protected] ~]$ kill -9 20081
  [1]+  Killed                  cat
  [[email protected] ~]$ sudo sysctl kernel.pid_max=10000
  kernel.pid_max = 10000
  [[email protected] ~]$ sudo su
  [[email protected] sfox]# echo 10000 > /proc/sys/kernel/pid_max
  [[email protected] sfox]# cat /proc/sys/kernel/pid_max 
  10000
  [[email protected] sfox]# exit
  exit
  [[email protected] ~]$ cat &
  [1] 378
  
  [1]+  Stopped                 cat
  [[email protected] ~]$
  
  

  0
• adamherst Posts: 25

  May 2015

  I thought the course was good and I learnt a lot. I went through everything twice before doing a third pass on only the parts relevant to the LFCS. I'm going to do a fourth pass on the parts that are relevant to the LFCE as a way of getting started on preparing for that exam.
  
  Thanks,
  
  Adam
  

  0
• ultraninja Posts: 20

  May 2015

  Hopefully 4 passes should do it :P
  
  I haven't worked out a strategy yet, I was just going to work through all the materials and labs then see how confident I felt. Maybe do a few passes.

  0
• adamherst Posts: 25

  May 2015

  Three passes did it to get my LFCS :-). And the third pass was really focused on just those sections of the course that would be on the exam. In retrospect it was worth it. I was able to perform a lot of the tasks by instinct. If I had to stop to think about the process and look up the details I'm sure I would have run out of time. As it was, there were a couple of questions I had to skip over and didn't have time to get back to.
  
  Thanks,
  
  Adam
  

  0