Specifying ssh key in ansible playbook file

ansible

Ansible playbook can specify the key used for ssh connection using --key-file on the command line.

ansible-playbook -i hosts playbook.yml --key-file "~/.ssh/mykey.pem"

Is it possible to specify the location of this key in playbook file instead of using --key-file on command line?

Because I want to write the location of this key into a var.yaml file, which will be read by ansible playbook with vars_files:.

The followings are parts of my configuration:

vars.yml file

key1: ~/.ssh/mykey1.pem
key2: ~/.ssh/mykey2.pem

playbook.yml file

---

- hosts: myHost
  remote_user: ubuntu
  key_file: {{ key1 }}  # This is not a valid syntax in ansible. Does there exist this kind of directive which allows me to specify the ssh key used for this connection?
  vars_files:
    - vars.yml
  tasks:
    - name: Echo a hello message
      command: echo hello

I've tried adding ansible_ssh_private_key_file under vars. But it doesn't work on my machine.

vars_files:
  - vars.yml
vars:
  ansible_ssh_private_key_file: "{{ key1 }}"
tasks:
  - name: Echo a hello message
    command: echo hello

If I run ansible-playbook with the playbook.yml above. I got the following error:

TASK [Gathering Facts] ******************************************************************************************************************************
Using module file /usr/local/lib/python2.7/site-packages/ansible/modules/system/setup.py
<192.168.5.100> ESTABLISH SSH CONNECTION FOR USER: ubuntu
<192.168.5.100> SSH: EXEC ssh -C -o ControlMaster=auto -o ControlPersist=60s -o StrictHostKeyChecking=no -o KbdInteractiveAuthentication=no -o PreferredAuthentications=gssapi-with-mic,gssapi-keyex,hostbased,publickey -o PasswordAuthentication=no -o User=ubuntu -o ConnectTimeout=10 -o ControlPath=/Users/myName/.ansible/cp/2d18691789 192.168.5.100 '/bin/sh -c '"'"'echo ~ && sleep 0'"'"''
<192.168.5.100> (255, '', 'Permission denied (publickey).\r\n')
fatal: [192.168.5.100]: UNREACHABLE! => {
    "changed": false,
    "msg": "Failed to connect to the host via ssh: Permission denied (publickey).\r\n",
    "unreachable": true
}
    to retry, use: --limit @/Users/myName/playbook.retry

I don't find the name of my key file in the ssh command. It's strange.

Best Answer

The variable name you're looking for is ansible_ssh_private_key_file.

You should set it at 'vars' level:

  • in the inventory file:

      myHost ansible_ssh_private_key_file=~/.ssh/mykey1.pem
  myOtherHost ansible_ssh_private_key_file=~/.ssh/mykey2.pem

  • in the host_vars:

      # host_vars/myHost.yml
  ansible_ssh_private_key_file: ~/.ssh/mykey1.pem

  # host_vars/myOtherHost.yml
  ansible_ssh_private_key_file: ~/.ssh/mykey2.pem

  • in a group_vars file if you use the same key for a group of hosts

  • in the vars section of an entry in a play:

      - hosts: myHost
    remote_user: ubuntu
    vars_files:
      - vars.yml
    vars:
      ansible_ssh_private_key_file: "{{ key1 }}"
    tasks:
      - name: Echo a hello message
        command: echo hello

  • in setting a fact in a play entry (task):

         - name: 'you name it'
       ansible.builtin.set_fact:
         ansible_ssh_private_key_file: "{{ key1 }}"

Inventory documentation

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