Ubuntu/Debian adds the following line in /etc/hosts.
127.0.1.1 <hostname>
https://www.debian.org/doc/manuals/debian-reference/ch05.en.html#_the_hostname_resolution
Kolla does not like this line in /etc/hosts and "kolla-ansible deploy" throws the error
"Hostname has to resolve to IP address of api_interface"
$ kolla-ansible deploy
TASK [rabbitmq : fail] *********************************************************
failed: [localhost] => (item={u'stdout': u'127.0.1.1 STREAM kolla-ubuntu\n127.0.1.1 DGRAM \n127.0.1.1 RAW ', u'cmd': [u'getent', u'ahostsv4', u'kolla-ubuntu'], u'end': u'2016-05-27 21:55:20.827997', '_ansible_no_log': False, u'warnings': [], u'changed': False, u'start': u'2016-05-27 21:55:20.823359', u'delta': u'0:00:00.004638', 'item': u'localhost', u'rc': 0, 'invocation': {'module_name': u'command', u'module_args': {u'creates': None, u'executable': None, u'chdir': None, u'_raw_params': u'getent ahostsv4 kolla-ubuntu', u'removes': None, u'warn': True, u'_uses_shell': False}}, 'stdout_lines': [u'127.0.1.1 STREAM kolla-ubuntu', u'127.0.1.1 DGRAM ', u'127.0.1.1 RAW '], u'stderr': u''}) => {"failed": true, "item": {"_ansible_no_log": false, "changed": false, "cmd": ["getent", "ahostsv4", "kolla-ubuntu"], "delta": "0:00:00.004638", "end": "2016-05-27 21:55:20.827997", "invocation": {"module_args": {"_raw_params": "getent ahostsv4 kolla-ubuntu", "_uses_shell": false, "chdir": null, "creates": null, "executable": null, "removes": null, "warn": true}, "module_name": "command"}, "item": "localhost", "rc": 0, "start": "2016-05-27 21:55:20.823359", "stderr": "", "stdout": "127.0.1.1 STREAM kolla-ubuntu\n127.0.1.1 DGRAM \n127.0.1.1 RAW ", "stdout_lines": ["127.0.1.1 STREAM kolla-ubuntu", "127.0.1.1 DGRAM ", "127.0.1.1 RAW "], "warnings": []}, "msg": "Hostname has to resolve to IP address of api_interface"}
PLAY RECAP *********************************************************************
localhost : ok=75 changed=23 unreachable=0 failed=1
Command failed ansible-playbook -i /usr/local/share/kolla/ansible/inventory/all-in-one -e @/etc/kolla/globals.yml -e @/etc/kolla/passwords.yml -e CONFIG_DIR=/etc/kolla -e action=deploy /usr/local/share/kolla/ansible/site.yml
Hence, add a precheck to check if the line "127.0.1.1 <hostname>" does not exist in /etc/hosts on Ubuntu. If it exists, the precheck must fail and the user must remove this line in /etc/hosts and deploy kolla.
"kolla-ansible deploy" passes on Ubuntu if "127.0.1.1 <hostname>" does not exist in /etc/hosts.
Fixed by https:/