Simple Ansible playbook for initial SSH setup

I use this scenario to quickly setup new Virtual Servers, which are delivered with the root and password access by default.

What the playbook does:

• Disables root user.
• Disables login via password (only with private key).
• Adds a new user (e. g. admin) with full sudo access (sudo with password).
• Changes default SSH port 22 to any other.

Requirements

• Ansible (tested on version 2.8.1)
• Root's password to destination server
• Server's distro must support sudo command.
• sshpass utility.

Notice — No any additional configurations like inventory file or ansible.cfg.

Generate private and public keys

ssh-keygen -t rsa -b 4096 -m PEM -f keyname

Replace keyname with your name (e. g. myserver). Enter passphrase if you want to (or skip this step).

This command will create two files: private key (without extension) and public key (ends with .pub).

Run a command

1. Download the playbook.

wget https://raw.githubusercontent.com/s-mokrushin/ansible-ssh-setup/master/setup-ssh.yml -O setup-ssh.yml

2. Prepare the command with your arguments.

ansible-playbook \
    setup-ssh.yml -i 123.123.123.123, \
    -u root \
    --become \
    --ask-pass \
    --extra-vars "admin_username=admin admin_password=verysecretpassword public_key_path=/path/to/keyname.pub ssh_port=22222"

• Change IP 123.123.123.123 to your server's IP address (keep character ",").
• Replace admin_user value with your name (if needed).
• Replace admin_password value with your password (use a strong password). This password used for sudo command.
• Replace public_key_path value with your public key path.
• Replace ssh_port value with any other allowed number (due to security reasons).

3. Run the command. Enter root's password.

Example output:

PLAY [Setup SSH] ***************************************************************

TASK [Gathering Facts] *********************************************************
ok: [123.123.123.123]

TASK [Add a new user named admin] **********************************************
changed: [123.123.123.123]

TASK [Add admin user to the sudoers] *******************************************
changed: [123.123.123.123]

TASK [Deploy SSH key] **********************************************************
changed: [123.123.123.123]

TASK [Disable password authentication] *****************************************
changed: [123.123.123.123]

TASK [Change default SSH port] *************************************************
changed: [123.123.123.123]

TASK [Disable Root Login] ******************************************************
changed: [123.123.123.123]

RUNNING HANDLER [restart ssh] **************************************************
changed: [123.123.123.123]

PLAY RECAP *********************************************************************
123.123.123.123               : ok=8    changed=7    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0   

Test it with a new connection

ssh -p 22222 -i /path/to/key admin@123.123.123.123

And run sudo su with your password for testing root access.