I am setting up 2 node hadoop cluster

[puneetjindal]

I am getting the following error

TASK: [master | prepare known_hosts entries] **********************************
failed: [172.17.0.9] => (item={'ip': '172.17.0.9', 'hostname': 'hadoop-master'}) => {"changed": true, "cmd": "ssh-keyscan -t rsa hadoop-master", "delta": "0:00:02.278891", "end": "2016-03-29 12:08:35.751114", "item": {"hostname": "hadoop-master", "ip": "172.17.0.9"}, "rc": 255, "start": "2016-03-29 12:08:33.472223", "warnings": []}
stderr: getaddrinfo hadoop-master: Name or service not known
failed: [172.17.0.9] => (item={'ip': '172.17.0.11', 'hostname': 'hadoop-data1'}) => {"changed": true, "cmd": "ssh-keyscan -t rsa hadoop-data1", "delta": "0:00:01.396855", "end": "2016-03-29 12:08:39.401873", "item": {"hostname": "hadoop-data1", "ip": "172.17.0.11"}, "rc": 255, "start": "2016-03-29 12:08:38.005018", "warnings": []}
stderr: getaddrinfo hadoop-data1: Name or service not known

[dwatrous]

At what point are you getting this error? Are you doing this locally or against openstack? The script may need a little attention to get it working for a purely local deployment again.