Looking for how to fix Ansible error failed to connect to the host via ssh? We can help you.

Ansible saves time by automation of server tasks.

However, improper host entry in the Ansible Inventory file or bad SSH configuration can create connection errors too.

At Bobcares, we get requests to fix Ansible errors as a part of our Server Management Services.

Today, let’s have a quick look at Ansible and see how our Support Engineers fix this error.

A quick look at Ansible

Ansible is an IT automation tool. It finds application in cloud server provisioning, configuration management, application deployment and so on.

The working of Ansible is quite simple. It connects to the hosts via SSH and pushes small programs or Ansible modules into the hosts. Ansible executes these modules and removes them when it is done.

in general, Ansible manages its hosts using the INI file. This file is better known as the Inventory file. The default location of this file is at /etc/ansible/hosts.

Why does Ansible shows failed to connect to the host via ssh?

Now let’s see why does the connection with Ansible host fails.

After adding any host to the Ansible Inventory file, we usually check the connection. We use the command,

ansible <Host_IP> -m ping

And, if we want to check the connection with all the host, we use the command,

ansible -m ping all

If the connection is successful, it shows the message,

<Host_IP> | SUCCESS => {
"ansible_facts": {
"discovered_interpreter_python": "/usr/bin/python"
},
"changed": false,
"ping": "pong"
}

But if Ansible fails to establish a connection with the host, the error message appears as,

Ansible connects to the host via SSH. Hence error shows up if there is an error in the Ansible SSH configuration. Otherwise, the host entry in the Inventory file can be wrong.

How we fix the error failed to connect to the host via ssh?

Now let’s see how our Support Engineers fix this error.

Initially, we find the reason for the error. For this, we debug the connection to the host by enabling verbosity. And we use the command,

ansible <Host_IP> -m ping -vvvv

So the error can be in the SSH configuration or the Inventory file.

1. Tweaking SSH

If the error is with SSH configuration, we tweak the SSH settings.

Usually, we login to the host using an SSH key-based authentication. Therefore, we check if the correct keys are present in appropriate files. That is, the public key of the Ansible server must be present in the .ssh/authorized_keys file of the host and vice versa.

Additionally, we check the SSH config file. That is /etc/ssh/ssd_config which holds how the host connects to a remote host via SSH.

2. Correct Inventory file

Another possible reason for the error is not specifying the host user in the Inventory file. So, we check the Inventory file and add the required variables next to Host IP. So the entry in the Inventory file appears as,

<Host_IP> ansible_sudo_pass=<password> ansible_ssh_user=<username>

Later, we check the connection with the host by pinging. Thus we make sure to fix the error.

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Conclusion

In short, Ansibles error failed to connect to the host via ssh occurs due to improper SSH configuration or incorrect Ansible Inventory file. Today, we saw how our Support Engineers fix this error.