How to set host_key_checking=false in ansible inventory file? - ansible

Question

I would like to use ansible-playbook command instead of 'vagrant provision'. However setting host_key_checking=false in the hosts file does not seem to work.
# hosts file
vagrant ansible_ssh_private_key_file=~/.vagrant.d/insecure_private_key
ansible_ssh_user=vagrant ansible_ssh_port=2222 ansible_ssh_host=127.0.0.1
host_key_checking=false
Is there a configuration variable outside of Vagrantfile that can override this value?

Answer 1

Due to the fact that I answered this in 2014, I have updated my answer to account for more recent versions of ansible.
Yes, you can do it at the host/inventory level (Which became possible on newer ansible versions) or global level:
inventory:
Add the following.
ansible_ssh_common_args='-o StrictHostKeyChecking=no'
host:
Add the following.
ansible_ssh_extra_args='-o StrictHostKeyChecking=no'
hosts/inventory options will work with connection type ssh and not paramiko. Some people may strongly argue that inventory and hosts is more secure because the scope is more limited.
global:
Ansible User Guide - Host Key Checking
You can do it either in the /etc/ansible/ansible.cfg or ~/.ansible.cfg file:
[defaults]
host_key_checking = False
Or you can setup and env variable (this might not work on newer ansible versions):
export ANSIBLE_HOST_KEY_CHECKING=False

Answer 2

Yes, you can set this on the inventory/host level.
With an already accepted answer present, I think this is a better answer to the question on how to handle this on the inventory level. I consider this more secure by isolating this insecure setting to the hosts required for this (e.g. test systems, local development machines).
What you can do at the inventory level is add
ansible_ssh_common_args='-o StrictHostKeyChecking=no'
or
ansible_ssh_extra_args='-o StrictHostKeyChecking=no'
to your host definition (see Ansible Behavioral Inventory Parameters).
This will work provided you use the ssh connection type, not paramiko or something else).
For example, a Vagrant host definition would look like…
vagrant ansible_port=2222 ansible_host=127.0.0.1 ansible_ssh_common_args='-o StrictHostKeyChecking=no'
or
vagrant ansible_port=2222 ansible_host=127.0.0.1 ansible_ssh_extra_args='-o StrictHostKeyChecking=no'
Running Ansible will then be successful without changing any environment variable.
$ ansible vagrant -i <path/to/hosts/file> -m ping
vagrant | SUCCESS => {
"changed": false,
"ping": "pong"
}
In case you want to do this for a group of hosts, here's a suggestion to make it a supplemental group var for an existing group like this:
[mytestsystems]
test[01:99].example.tld
[insecuressh:children]
mytestsystems
[insecuressh:vars]
ansible_ssh_common_args='-o StrictHostKeyChecking=no'

Answer 3

I could not use:
ansible_ssh_common_args='-o StrictHostKeyChecking=no'
in inventory file. It seems ansible does not consider this option in my case (ansible 2.0.1.0 from pip in ubuntu 14.04)
I decided to use:
server ansible_host=192.168.1.1 ansible_ssh_common_args= '-o UserKnownHostsFile=/dev/null'
It helped me.
Also you could set this variable in group instead for each host:
[servers_group:vars]
ansible_ssh_common_args='-o UserKnownHostsFile=/dev/null'

Answer 4

In /etc/ansible/ansible.cfg uncomment the line:
host_key_check = False
and in /etc/ansible/hosts uncomment the line
client_ansible ansible_ssh_host=10.1.1.1 ansible_ssh_user=root ansible_ssh_pass=12345678
That's all

Answer 5

Adding following to ansible config worked while using ansible ad-hoc commands:
[ssh_connection]
# ssh arguments to use
ssh_args = -o StrictHostKeyChecking=no
Ansible Version
ansible 2.1.6.0
config file = /etc/ansible/ansible.cfg

Answer 6

You set these configs either in the /etc/ansible/ansible.cfg or ~/.ansible.cfg or ansible.cfg(in your current directory) file
[ssh_connection]
ssh_args = -C -o ControlMaster=auto -o ControlPersist=60s -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no
tested with ansible 2.9.6 in ubuntu 20.04