Ansible is one of the most recent tools released by Red Hat and one of the best choices for Developers and DevOps engineers to automate almost everything inside a new server. It is free and open-source, and trust me, configuring remote servers has never been so easy.
In this tutorial, I intend to show you how to install and start to use this powerful tool.
First, you will need an Ansible controller host to manage all your nodes. This host could be your localhost, don't worry, Ansible will work no matter which operating system you use. I am using Ubuntu, but the installation steps for any other os are almost the same.
Let's install Ansible using apt.
$ sudo apt install ansible
Once the installation finished, run
$ ansible --version
If the package installation was successful, you should see something like this.
Now your ansible controller is working, pretty easy right?
Let's set up your nodes, open the
/etc/ansible/hosts file with your preferred editor, you should see this template
# This is the default ansible 'hosts' file. # # It should live in /etc/ansible/hosts # # - Comments begin with the '#' character # - Blank lines are ignored # - Groups of hosts are delimited by [header] elements # - You can enter hostnames or ip addresses # - A hostname/ip can be a member of multiple groups # Ex 1: Ungrouped hosts, specify before any group headers. #green.example.com #blue.example.com #192.168.100.1 #192.168.100.10 # Ex 2: A collection of hosts belonging to the 'webservers' group#[webservers] #alpha.example.org #beta.example.org #192.168.1.100 #192.168.1.110 # If you have multiple hosts following a pattern you can specify # them like this: #www[001:006].example.com# Ex 3: A collection of database servers in the 'dbservers' group #[dbservers] # #db01.intranet.mydomain.net #db02.intranet.mydomain.net #10.25.1.56 #10.25.1.57# Here's another example of host ranges, this time there are no # leading 0s:#db-[99:101]-node.example.com
You can add your hosts at the bottom of the file or delete all the content and replace it with your hosts. The only rule is to follow the syntax below.
# Linux host # host_alias ansible_host=<host_ip_or_url> ansible_connection=ssh ansible_user=<host_user> ansible_ssh_pass=<ssh_password_for_user> # Windows host # host_alias ansible_host=<host_ip_or_url> ansible_connection=winrm ansible_user=<host_user> ansible_password=<password_for_user> # I am adding two servers, both of them are Linux servers web1 ansible_host=my.webserver.com ansible_connection=ssh ansible_user=root ansible_ssh_pass=Passw0rd db1 ansible_host=my.databaseserver.com ansible_connection=ssh ansible_user=root ansible_ssh_server=Passw0rd
Now, add some groups for your servers. Groups let you run commands and scripts on multiple hosts simultaneously.
[web_nodes] web1 ansible_host=my.webserver.com ansible_connection=ssh ansible_user=root ansible_ssh_pass=Passw0rd [db_nodes] db1 ansible_host=my.databaseserver.com ansible_connection=ssh ansible_user=root ansible_ssh_server=Passw0rd
Save your changes and close the file.
Ansible depends on sshpass package, install it running the following command
$ sudo apt install sshpass
The only remaining step is to connect to your hosts through ssh; this is for adding your host's fingerprints to the
$ ssh email@example.com $ ssh firstname.lastname@example.org
Now, try your hosts by running:
$ # Ansible has an 'all' group which contains all your defined hosts $ ansible all -m ping
If everything is going well, you will see a similar output
Your hosts are ready to be used through Ansible. Please create a new folder in your home directory.
$ mdkir ~/ansible-tutorial $ cd ~/ansible-tutorial
Ansible's scripts are just YAML files. If you have worked with YAML before, this step will be straightforward.
Open a new playbook.yml file and add the following lines
- name: My playbook hosts: web1 tasks: - name: Runnig date command: date
nameis an alias for the playbook
hostsdefines the hosts to run the playbook, can be a group
tasksis an array that holds the actions or modules to use
Save your changes and close the file, now run it with
$ ansible-playbook playbook.yml
You should see a similar output as below
A simple, real-life example
You learned some new things so far
- Install and configure an Ansible controller
- Add a new playbook
- Run it on your hosts
Now it is time to learn how we can use Ansible in a real-life scenario.
For this example, you are going to install and run an Nginx webserver.
Let's create a new playbook
$ vim nginx-playbook.yml
To start to write this playbook, add a name and the host where the Nginx should be running (remember the identation)
- name: 'Install and deploy nginx' hosts: web1
Now, add the tasks, in this case you will need to define two actions.
Install the latest Nginx version
Start Nginx server
tasks: - name: 'Install Nginx latest version' apt: name: nginx state: latest
This task looks for Nginx on the target host. If Ansible finds Nginx's latest version, the installation won't happen.
- name: 'Run Nginx' service: name: nginx state: started
And this task checks if the Nginx server is already running. If it is not, then the step is skipped.
Your complete nginx-playbook.yml should look like this
- name: 'Install and deploy nginx' hosts: web1 tasks: - name: 'Install Nginx latest version' apt: name: nginx state: latest - name: 'Run Nginx' service: name: nginx state: started
Save your changes, and now, try it!
Since we are installing a package in your host, you will need to add the '-b' flag to the playbook command.
$ ansible-playbook nginx-playbook.yml -b $ # -b or --become grants root privileges to ansible user.
And finally let's check the browser!
Ansible is a great ally; it makes it easy to install and deploy things in all your servers. Sure, this is just an introductory tutorial, but this tool has one module for everything you need to automate. You can find all always available here.
Thanks for reading. Every feedback, comment, or sharing is highly appreciated!
Top comments (0)