Ansible is an IT automation tool. It simplifies cloud computing, configuration management, program setup, intra-service orchestration, and several other IT needs.
Ansible uses a very simple language (YAML, in the form of Ansible Playbooks) that allows you to spell out your automation jobs in a way that means plain English.
While there are many popular configuration management systems available for Linux systems, such as Chef, Ansible is the simplest configuration management systems to get started with.
Ansible works by configuring client machines from a computer that has the Ansible components installed and configured. It communicates over normal SSH channels to retrieve information from remote machines. This means that any computer that you can administer through SSH, you can also administer through Ansible.
Requirements:
- You have an account and are logged into console.scaleway.com
- You have an Ubuntu Bionic server
- You have configured your SSH Key
1 . Connect to your server using SSH:
ssh root@SERVER_IP
If you do not know your server IP, you can list your existing servers using scw ps (Scaleway CLI). For more information on the Scaleway CLI, refer to the tutorial on the Scaleway Command Line Interface.
The server IP can also be retrieved from the Scaleway Console. Once logged in, check the IP Adresses in the Servers tab of the left menu.
Note: If you use the root user, you can remove the
sudobefore each command.
2 . Update Ubuntu packet manager:
sudo apt-get update
3 . Upgrade the Ubuntu packages already installed:
sudo apt-get upgrade
1 . Update your package index and install the software-properties-common package. This software will make it easier to manage this and other independent software repositories. Add the Ansible PPA and refresh your system’s package index once again.
apt install software-properties-common
apt-add-repository ppa:ansible/ansible
apt update
2 . Install the Ansible software
apt install ansible
3 . Check that the installation is successful
ansible --version
which returns
ansible 2.6.1
config file = /etc/ansible/ansible.cfg
configured module search path = [u'/root/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
ansible python module location = /usr/lib/python2.7/dist-packages/ansible
executable location = /usr/bin/ansible
python version = 2.7.15rc1 (default, Apr 15 2018, 21:51:34) [GCC 7.3.0]
To learn more about different methods for installing Ansible, refer to the official Ansible Documentation.
1 . Generate a ssh key
ssh-keygen -t rsa
which returns
Enter file in which to save the key (/home/user/.ssh/id_rsa):
it is recommended to press Enter to generate and store the ssh key to the default location.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
2 . (OPTIONAL) To avoid the prompt of your passphrase, launch exec ssh-agent $SHELL to run a ssh agent, and ssh-add ~/.ssh/id_rsa to add your key to the ssh agent.
3 . Use the cat command to print the contents of your non-root user’s SSH public key file to the terminal’s output
cat ~/.ssh/id_rsa.pub
4 . Copy the resulting output to your clipboard, then open a new terminal and connect to one of your Ansible hosts using SSH
ssh root@ansible_host_ip
5 . Open the authorized_keys within the ~/.ssh directory
nano ~/.ssh/authorized_keys
6 . In the file, paste your Ansible server user’s SSH key, then save the file and close the editor.
7 . Install Python 3 on the host in order for Ansible to communicate with it.
Note: Python 2 is almost at its EOF and Ubuntu Bionic Beaver does not integrate version 3 by default.
apt update
apt install python3
8 . To make Ansbile wirking with Python 3, specify the Python interpreter in a var or in the inventory.
- hosts: all
vars:
ansible_python_interpreter: /usr/bin/env python3
host1 ansible_ssh_host=X.X.X.X ansible_python_interpreter=/usr/bin/env python3
9 . IMPORTANT: Under Credentials Paste your SSH key in the Scaleway Console and click Use this SSH Key
10 . Run the exit command to close the connection to the client
Repeat this process for each server you intend to control with your Ansible server. Next, we’ll configure the Ansible server to connect to these hosts using Ansible’s hosts file.
1 . Ansible tracks of all of the servers through an inventory file. We need to set up this file first before we can communicate with our other computers.
On your Ansible server, open the file
sudo nano /etc/ansible/hosts
In our example, we have two servers controlled with Ansible. The hosts file is fairly flexible and can be configured in a few different ways. The syntax we are going to use, though, looks like this:
[group_name]
alias ansible_ssh_host=your_server_ip
In this example, group_name is an organizational tag that lets you refer to any servers listed under it with one word, while alias is just a name to refer to one specific server. For the tutorial purpose, our host file looks like this:
[servers]
host1 ansible_ssh_host=X.X.X.X
host2 ansible_ssh_host=X.X.X.X
2 . Save and close this file when you are finished.
If you want to specify configuration details for every server, regardless of group association, you can put those details in a file at /etc/ansible/group_vars/all. Individual hosts can be configured by creating files named after their alias under a directory at /etc/ansible/host_vars.
Ping all of the servers
ansible -m ping all
which returns
host1 | SUCCESS => {
"changed": false,
"ping": "pong"
}
host2 | SUCCESS => {
"changed": false,
"ping": "pong"
}
The all means all hosts listed in the hosts file. However it is also possible to:
ansible -m ping serversansible -m ping host1ansible -m ping host1:host2For more information on Ansible commands or playbook, refer to the official Ansible documentation.