The task includes an option with an undefined variable.

[xerox-xeon]

TASK [scm : set_fact] *************************************************************************************************************************************************************************
task path: /home/deploy/cloudera-playbook/roles/scm/tasks/cms.yml:9
fatal: [cdh1.dev]: FAILED! => {
"msg": "The task includes an option with an undefined variable. The error was: 'dict object' has no attribute u'cdh1.dev'\n\nThe error appears to be in '/home/deploy/cloudera-playbook/roles/scm/tasks/cms.yml': line 9, column 3, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n\n- set_fact:\n ^ here\n"
}

[xerox-xeon]

ansible --version
ansible 2.9.3
config file = /etc/ansible/ansible.cfg
configured module search path = [u'/root/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
ansible python module location = /usr/lib/python2.7/site-packages/ansible
executable location = /usr/bin/ansible
python version = 2.7.5 (default, Aug 7 2019, 00:51:29) [GCC 4.8.5 20150623 (Red Hat 4.8.5-39)]

[xerox-xeon]

Get the host identifiers and names from Cloudera Manager
{
"items": [

]
}

[Jimvin]

If the list of hosts is empty then this suggests that the Cloudera Manager agents may not be able to report in and register. If you log into Cloudera Manager is the list of hosts empty? Check the agent logs to see if there's any indication there as to why they are unable to register with the server.