Increasing `ulimit -u` settings temporarily in OSX Yosemite

Question

I'm trying to temporarily (without restarting the machine, just for test that starts a JVM) increase the number of processes to 2048 in OSX Yosemite but I'm unable to do so.

First, I tried calling ulimit -S -u 2048 but that returns:

ulimit: value exceeds hard limit

The hard limit is 1064:

$ ulimit -Hu
1064

I've used sysctl to change the limit of kern.maxproc and kern.maxprocperuid and that worked fine:

$ sudo sysctl -w kern.maxprocperuid=2048
$ sudo sysctl -w kern.maxproc=2048
$ sysctl kern.maxprocperuid kern.maxproc
kern.maxprocperuid: 2048
kern.maxproc: 2048

I have also tried to change the limits of launchctl maxproc and that seemed to work fine:

$ sudo launchctl limit maxproc 2048 2048
$ launchctl limit maxproc
maxproc     2048           2048

However, in spite of changing all this, I'm still unable to change the upper limit of ulimit -u.

The reason I'm doing all of this is cos I'm having some OOME: Unable to create native thread errors in a JVM that's started from a MVN test, even though I've passed to it -Xss265k -Xmx2g.

Any ideas?

Answer 1

Even though you only want to change the limit temporarily, the change must be done in a persistent way by creating /Library/LaunchDaemons/limit.maxproc.plist file, owned by root:wheel and permissions 644 with these contents:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
  <plist version="1.0">
    <dict>
      <key>Label</key>
        <string>limit.maxproc</string>
      <key>ProgramArguments</key>
        <array>
          <string>launchctl</string>
          <string>limit</string>
          <string>maxproc</string>
          <string>2048</string>
          <string>2048</string>
        </array>
      <key>RunAtLoad</key>
        <true />
      <key>ServiceIPC</key>
        <false />
    </dict>
  </plist>

Thanks to Jason Greene for the help with this!