Article about known_hosts: What is known_hosts File in Linux

1. Here is a video tutorial

Scripts and configuration files are available here:

Working recommended solution, but only in the environment that is not compromised.

1. Cleanup known_hosts in /home/user/.ssh directory
2. Run the ansible playbook with the below command:

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ansible-playbook ssh-session.yaml

3. Break it with ctrl+c
4. Run the below command:

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./ssh-session.ssh

5. Check the result in known_hosts

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cat ~/.ssh/known_hosts

6. You will see all the entries added by ssh.
7. Run the ansible playbook with the below command one more time:

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ansible-playbook ssh-session.yaml

8. Type yes few times and then break it with ctrl+c
9. Check the result in the screen.
10. Cleanup known_hosts in /home/user/.ssh directory and then run the ansible playbook with the below command:

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ansible-playbook ssh-session.yaml --ssh-common-args='-o StrictHostKeyChecking=no'

Problem is solved.

Working solution that I do not recommend

1. Cleanup known_hosts in /home/user/.ssh directory
2. Display global variables with the below command:

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export

3. Perform the below command:

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export ANSIBLE_HOST_KEY_CHECKING=False

4. Connect using ssh to the remote host

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ssh username@hostname

5. Run the ansible playbook with the below command:

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ansible-playbook ssh-session.yaml

6. Check the result in known_hosts

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cat ~/.ssh/known_hosts

7. See do you have entries added into known_hosts

Solution that I have found in the Internet that I really do not recommend

1. Run the ansible playbook with the below command:

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ansible-playbook ssh-keyscan.yaml

2. Check the result in known_hosts

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cat ~/.ssh/known_hosts

3. Get rid of unecessary entries in known_hosts
4. Run the ansible playbook with the below command:

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ansible-playbook ssh-session.yaml

5. Watch the mentioned video to understand what happened and why.