Ansible is an open source automation platform that can manage hosts over
the ssh protocol. Ansible is described in three words: Simple, Powerful, Agentless.
It is considered simple due to providing human-readable automation. The playbooks
are written using YAML syntax
that requires no coding skills and each task within the playbook is executed in
order. Ansible is considered powerful because of its flexibility to automate
your entire app lifecycle. Ansible is agentless thus doesn’t require installing
anything on the managed remote hosts. It uses OpenSSH or WinRM to run tasks and
execute Ansible modules to the managed hosts.
The Ansible architecture consists of two types of machines labeled: Control Machine and Managed Nodes. Ansible is installed on the control machine. The control machine contains all of the playbooks that are to be run against your managed nodes. The managed nodes are listed in an inventory file. The inventory of the managed hosts is either a simple static text file or a dynamic inventory file created by a set of scripts written by the end user to determine the IPs or the hostname of the hosts that are to be managed. For the purposes of this lab, the inventory files will be a static text file. Inventory files include the ability to group nodes together for easier manageability. For example grouping all the database nodes in a group labeled database.
After Ansible takes the input of the nodes to be managed, a playbook that contains at least one play is executed for the managed nodes that are selected. A play executes a series of tasks in order on the managed nodes. Each task runs a specific Ansible module that is specified within your Ansible playbook. The tasks are what may change the state of the managed hosts as they may install packages on a system, modify files, and/or change configuration settings. For the purposes of this lab, the main focus will be on using OpenStack Ansible modules to manage our OpenStack node.
A pictorial representation of Ansible’s architecture from the Ansible site can be seen below:
The subsequent sections go into the installation of Ansible and their prerequisites.
In order to use Ansible playbooks against our OpenStack environment, we must first install the required prerequisites. Your workstation requires the following to be installed (if not already):
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Text editor (such as Sublime Text)
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Note
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The Fedora VirtualBox image pre-installs all the required prerequisites. Please reference the section VirtualBox Setup if not planning on using your local laptop/workstation. The install instructions for the different OS vendors may be skipped if using the VirtualBox image. |
The preferred way to install Ansible on the macOS is via the Python package
manager pip. Launch a terminal and execute the following commands:
pipsudo easy_install pip
pipsudo pip install ansible
Verify that Ansible is successfully installed by running:
ansible --version
The expected output is similar to the following:
$ ansible 2.5.0 config file = /etc/ansible/ansible.cfg configured module search path = [u'/home/rlopez/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules'] ansible python module location = /usr/lib/python2.7/site-packages/ansible executable location = /usr/bin/ansible python version = 2.7.14 (default, Feb 27 2018, 20:43:24) [GCC 7.3.1 20180130 (Red Hat 7.3.1-2)]
A second method of deploying Ansible for the macOS, is using Homebrew. Launch a terminal and execute the following commands:
brewbrew install ansible
Verify that Ansible is successfully installed by running:
ansible --version
The expected output is similar to the following:
$ ansible 2.5.0 config file = /etc/ansible/ansible.cfg configured module search path = [u'/home/rlopez/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules'] ansible python module location = /usr/lib/python2.7/site-packages/ansible executable location = /usr/bin/ansible python version = 2.7.14 (default, Feb 27 2018, 20:43:24) [GCC 7.3.1 20180130 (Red Hat 7.3.1-2)]
Within the macOS, git is installed with the Xcode Command Line Tools. Prior
to installation of git, verify if git is already installed within the macOS
as follows via a terminal:
git --versionIf git is not installed, a version of git could be downloaded and installed
here.
Ansible in Microsoft Windows could be installed using Cygwin. Installation instructions on how to install Cygwin are located at: http://cygwin.com/install.html .
The following list of packages are required during the Cygwin installation:
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curl -
python (2.7.x) -
python-jinja -
python-crypto -
python-openssl -
python-setuptools -
git (1.7.x) -
vim -
openssh -
openssl -
openssl-devel -
gcc-g++ -
libffi-devel -
libmysqlclient-devel
After this install PyYAML and Jinja2 separately, as they are not
available in Cygwin.
Once installed, open Cygwin to complete the installation of Ansible.
ssh-keygen -t rsa
pipeasy_install-2.7 pip
pip install ansible
The following subsections provide steps to install Ansible and git for
the following Linux distributions:
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Fedora
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Red Hat Enterprise Linux (RHEL)
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CentOS
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Ubuntu
The preferred method to install Ansible and git on Fedora is using the
dnf package manager.
As a sudo user,
sudo dnf -y install ansible git
The preferred method to install Ansible and git on RHEL is using the
yum package manager.
As a sudo user, perform the following steps.
sudo subscription-manager repos --enable=rhel-7-server-rpms --enable=rhel-7-server-ansible-2-rpms
As a sudo user, install the following packages
sudo yum -y install ansible git
The preferred method to install Ansible and git on CentOS is using the
yum package manager.
As a sudo user,
sudo yum -y install ansible git
The preferred method to install Ansible and git on Ubuntu is using the
apt-get command line tool that works with APT software packages.
As a sudo user,
sudo apt-get update sudo apt-get install software-properties-common sudo apt-add-repository ppa:ansible/ansible sudo apt-get update sudo apt-get install ansible git
If installing Ansible and/or git on your laptop/workstation is not your
preferred method, a VirtualBox image is provided that may be used as your
workstation to complete the corresponding labs.
Prior to using the provided Fedora VirtualBox Image, download and install VirtualBox for your corresponding Operating System. Visit https://www.virtualbox.org/wiki/Downloads to complete the installation.
Below is a table with the specifics regarding the VirtualBox image.
VirtualBox Image Location |
username |
password |
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If interested in running a Fedora workstation using Vagrant, the following steps provide the setup.
The steps below are done on a Fedora machine.
# Install Vagrant dnf install -y vagrant # Install VirtualBox dnf install -y VirtualBox # Create a folder on your system that will store the Vagrantfile to run your VM. mkdir ~/openstack-vagrant cd ~/openstack-vagrant # Initialize the 'box' which creates the Vagrantfile. We will be creating a Fedora 27 box. vagrant init fedora/27-cloud-base #Boot the Fedora 27 server using the following command: vagrant up --provider virtualbox #SSH into the vagrant box using the vagrant ssh command: vagrant ssh