Home OpenStack-Ansible Installation Guide
The default MaxSessions setting for the OpenSSH Daemon is 10. Each Ansible fork makes use of a Session. By default, Ansible sets the number of forks to 5. However, you can increase the number of forks used in order to improve deployment performance in large environments.
This may be done on a permanent basis by adding the forks configuration entry in ansible.cfg, or for a particular playbook execution by using the --forks CLI parameter. For example, to execute the os-keystone-install.yml playbook using 10 forks:
# openstack-ansible --forks 10 os-keystone-install.yml