How to adjust ulimits for different OpenStack containers?

Issue

• How to change ulimit parameters for different OpenStack containers?

• Increase ulimit parameters for the following containers:

  • cinder-volume
  • neutron-dhcp
  • neutron-l3
  • neutron-ovs-agent
  • nova-compute

• Neutron DHCP agent logs the following error:

  File "/usr/lib64/python2.7/subprocess.py", line 1224, in _execute_child\n    self.pid = os.fork()\n', 'OSError: [Errno 12] Cannot allocate memory\n']: OSError: [Errno 12] Cannot allocate memory
  

• nova-compute ... <... socket resumed> ) = -1 EMFILE (Too many open files)