Create target VM

Create a fresh VM with vagrant to use ansible on it with the following configuration

Vagrant.configure("2") do |config|
  config.vm.box = "ubuntu/xenial64"

  config.vm.network :private_network, ip: "192.168.0.2"

  config.ssh.forward_agent    = true
  config.ssh.insert_key       = false
  config.ssh.private_key_path =  ["~/.vagrant.d/insecure_private_key","~/.ssh/id_rsa"]
  config.vm.provision :shell, privileged: false do |s|
    ssh_pub_key = File.readlines("#{Dir.home}/.ssh/id_rsa.pub").first.strip
    s.inline = <<-SHELL
      echo #{ssh_pub_key} >> /home/$USER/.ssh/authorized_keys
      sudo bash -c "echo #{ssh_pub_key} >> /root/.ssh/authorized_keys"
      sudo apt-get update
      sudo apt-get install -y python
    SHELL
  end
end

Ansible use ssh to connect to target VM and execute command on machines.
This configuration add your local machine ssh keys to the accepted configuration of the custom VM.

Installation

The instruction for installation can be found here

Inventory

Ansible works against multiple systems in your infrastructure at the same time. It does this by selecting portions of systems listed in Ansible’s inventory, which defaults to being saved in the location /etc/ansible/hosts. You can specify a different inventory file using the -i option on the command line.

To work on your new configured VM, add it’s ip to the ansible inventory file /etc/ansible/hosts

echo 192.168.0.2 >> /etc/ansible/hosts

By doing this you add your VM to the global inventory of ansible in the all group (if you don’t have already some groupe configured in this file …).

You can test the connection to your VM with the ansible command, using the ping module.

ansible all -u vagrant -m ping

The -u option define the suer to connect with on the VM.
Th -m define the module to be executed on VMs from the all group

Connection user

If you would like to access sudo mode, there are also flags to do that:

# as bruce
$ ansible all -m ping -u bruce
# as bruce, sudoing to root
$ ansible all -m ping -u bruce -b
# as bruce, sudoing to batman
$ ansible all -m ping -u bruce -b --become-user batman

(The sudo implementation is changeable in Ansible’s configuration file if you happen to want to use a sudo replacement. Flags passed to sudo (like -H) can also be set there.)

Ad-hoc commands

Now run a live command on all of your nodes:

$ ansible all -u vagrant -a "/bin/echo hello"

Congratulations! You’ve just contacted your nodes with Ansible.
It’s soon going to be time to:

read about some more real-world cases in Introduction To Ad-Hoc Commands
explore what you can do with different modules
learn about the Ansible Working With Playbooks language. Ansible is not just about running commands, it also has powerful configuration management and deployment features.

There’s more to explore, but you already have a fully working infrastructure!

Excercice

Start multiple VMs and configure ansible to run hostname to all your VM with one command

Getting Started with Ansible

Published 09-09-2018 22:06:59