For using Ansible it’s required to have a working set of ssh-keys already deployed.
If you get a set of systems that have not been provisioned by you and are missing the SSH keys, having it fixed might take a while if doing it manually. Good news is that you can use a script in expect to cover this part:
#!/usr/bin/expect -f
# set Variables
set password [lrange $argv 0 0]
set ipaddr [lrange $argv 1 1]
# now connect to remote system
spawn ssh-copy-id root@$ipaddr
match_max 100000
# Check for initial connection (add key of host)
set timeout 5
expect "yes/no" { send -- "yes\r" }
# Check for password prmpt
set timeout 120
# Look for passwod prompt
expect "password:" { send -- "$password\r" }
# send blank line (\r) to come back
send -- "\n"
expect eof
This script, when used like:
sshkeyscopy letmein mynewhost
Will connect to the specified host, using letmein as password to authenticate, and use the ssh-copy-id command to load your ssh keys.
To further automate, we can create an ansible playbook like this:
---
- hosts: all
user: root
vars:
rootpassword: letmein
tasks:
- name: Copy ssh keys
shell: sshkeyscopy {{ rootpassword }} {{ item }}
with_items: "{{ groups['all'] }}"
delegate_to: localhost
Using this playbook, we will delegate to localhost the connection to all of the specified hosts in the inventory and use this expect script to load the keys.
Once it’s done, we can test that we can ssh into the hosts without password being prompted.