If you have old CentOS/RedHat VMs that you can't run Ansible playbooks on, receiving the error "Error: ansible requires a json module, none found!," you can bootstrap these machines to work with Ansible with the following raw command.
ansible raw command
ansible vms -i oldvms -u jsmith -s -U root -m raw -a "sudo yum install -y python-simplejson" -k -K
inventory file: oldvms
[vms] 192.168.1.1 192.168.1.2 192.168.1.3 192.168.1.4
You may find that if your old VMs have bad .repo files in /etc/yum.repos.d that don't resolve, you'll have to move them out of the way before you can successfully install anything with yum. In this case just:
ansible vms -i oldvms -u jsmith -s -U root -m raw -a "sudo mv /etc/yum.repos.d/badrepo.repo /etc/yum.repos.d/badrepo.repo.off" -k -K