Can't disable Ansible's host key checking

Question

I'm using Ansible 1.5.4 to provision my Vagrant 1.4.3 box on Ubuntu 14.04 LTS.

I'm getting the following error message in verbose mode:

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

I can do: export ANSIBLE_HOST_KEY_CHECKING=False and I have following lines in my ~/.ansible.cfg:

[defaults]
host_key_checking = False

But it doesn't help.

What could be the problem? Thank you!

UPDATE #1

I'm calling it directly like this (without using vagrant command):

ansible-playbook playbook.yml -i inventory.ini --user=vagrant --ask-pass -vvvv

The inventory is:

[default]
localhost:2222

Answer 1

You'll need to set it via the Vagrantfile of the project. When the Vagrant Ansible provisioner makes the call to ansible-playbook it always sets the value of the ANSIBLE_HOST_KEY_CHECKING environment variable.

Ansible itself takes the value of the environment variable if present. Therefore Vagrant will override the value used in your ansible.cfg.

Therefore you just need something like:

machine.vm.provision :ansible do |ansible|
  ansible.host_key_checking = false
  # etc.
end