Configure Servers Using Ansible

Ansible is a server configuration tool. It is an open source software that automates software provisioning, configuration management, and application deployment. Ansible connects via SSH, remote PowerShell or via other remote APIs.

Generally, Ansible is used as a main option for deploying software built by Jenkins to test servers.

This document describes steps used to have Ansible configures and controls three separate OS environments (servers) via the use of SSH. Once followed through the end, you should have three configured servers and one playbook to rule them all.

For the purpose of demonstrating how Ansible is used to configure and provision remote servers via SSH, let's refer to the table below. We have a local controller node (ubuntu16), and three remote nodes (raspberrypi3, linux1rhel, azuresles12). Note, it is suggested that all nodes have the same user account. e.g. hurricanemark. In the case of different user account, specify it in ~/.ssh/config.

Ansible Controller	Test Server	IP_addr	User
ubuntu16		192.168.0.10	hurricanemark
	raspberrypi3	192.168.0.35	hurricanemark
	linux1rhel	148.100.99.23	jakeo
	azuresles12	13.99.130.110	hurricanemark

Aliases for SSH:

Content of ~/.ssh/config on ubuntu16

Host raspberrypi3
  HostName 192.168.0.35
  User hurricanemark
Host linux1rhel
  HostName 148.100.99.23
  User jakeo
  IdentityFile ~/.ssh/identity_linux1_priv
Host azuresles12
  HostName 13.99.130.110
  User hurricanemark

Make sure to change permission on ~/.ssh/identity_linux1_priv to 400. You can now reference ip address 148.100.99.23 by its alias linux1rhel

hurricanemark@ubuntu16> ssh linux1rhel

Connect to servers with openssh

hurricanemark@ubuntu16> ssh-keygen

hurricanemark@ubuntu16> ssh-copy-id hurricanemark@raspberrypi3

hurricanemark@ubuntu16> ssh-copy-id hurricanemark@azuresles12

hurricanemark@ubuntu16> ssh-copy-id -i ~/.ssh/identity_linux1_priv jakeo@linux1rhel

Install ansible on the controller

The attraction of this tool is this is the only installation you will need to run Ansible.

hurricanemark@ubuntu16# apt-add-repository ppa:ansible/ansible

hurricanemark@ubuntu16# apt-get update

hurricanemark@ubuntu16# apt install ansible

hurricanemark@ubuntu16# ansible -version

Create ansible workspace

1. Create private workspace ( in your home directory).

hurricanemark@ubuntu16> cp -R /etc/ansible ~/myansible

hurricanemark@ubuntu16> vi ~/myansible/ansible.cfg

Modify this line

	inventory	= hosts

hurricanemark@ubuntu16> vi hosts

Replace content with

raspberrypi3
    azuresles12
    linux1rhel

2. Customize basic tasks pertain to common requirements to your automate server operation. We create separate main.yml according to OS platform differences. For each main.yml, we define task to install python3.

• Create basic common tasks for Ubuntu platforms

hurricanemark@ubuntu16> mkdir -p ~/myansible/roles/basic4ubuntu/tasks

hurricanemark@ubuntu16> vi ~/myansible/roles/basic4ubuntu/tasks/main.yml

	- name: "Installing python3"
	   apt: pkg=python3 state=present

• Create basic common tasks for RHEL platforms

hurricanemark@ubuntu16> mkdir -p ~/myansible/roles/basic4rhel/tasks

hurricanemark@ubuntu16> vi ~/myansible/roles/basic4rhel/tasks/main.yml

	- name: "Installing python3"
	   yum: pkg=python3 state=present

• Create basic common tasks for SLES platforms

hurricanemark@ubuntu16> mkdir -p ~/myansible/roles/basic4sles/tasks

hurricanemark@ubuntu16> vi ~/myansible/roles/basic4sles/tasks/main.yml

	- name: "Installing python3"
	  zypper: pkg=python3 state=present

• Create ansible playbook for controller node

hurricanemark@ubuntu16> vi ~/myansible/playbook.yml

	---
    - hosts: raspberrypi3
    	become: true
        roles:
        	- basic4ubuntu
            
    - hosts: linux1rhel
    	become: true
        roles:
        	- basic4rhel
            
    - hosts: azuresles12
    	become: true
        roles:
        	- basic4sles

Ansible Ad-hoc commands

Let's test the interconnectivity we have set up thus far.

hurricanemark@ubuntu16> ansible -version

hurricanemark@ubuntu16> ansible -m shell -a 'whoami' all

hurricanemark@ubuntu16> ansible -m shell -a 'ping -c1 www.google.com' all

hurricanemark@ubuntu16> ansible -b -K -m user -a 'name=hurricanemark' all

Now, run basic tasks on all three servers.

hurricanemark@ubuntu16> ansible-playbook -K ~/myansible/playbook.yml

hurricanemark@ubuntu16> ansible-playbook playbook_aws.yml

Pain points

We engineers and developers, would instantly recognize the pain points in doing the above. I can name a few: It is labor intensive, no conditional failsafe for diferrences in OS/platform dependencies, etc. However, we need to learn how to crawl before we can walk.

In order for an organization to grow, infrastructure as code is a neccessity. In my future checkin to github repo will address grouping inventory technique in configuring ansible.cfg and hosts Further down the line, checkout Terraform and all of its modules terraform module registry.

Happy DevOps 'ing.

References

Ansible ad-hoc commands

Ben's IT Lesson

Feedback

https://github.com/hurricanemark

email