/Ansible

Ansible - automation tool for configuration management, playbook provisioning of multiple machines simulatenously. AWS Creation of Services such as EC2 and VPC.

Primary LanguageHTML

Ansible

  • Configuration management with Ansible
  • IAC Infrastructure as code
  • Multi Server Environment

Infrastructure as code (IAC)

  • We use IAC to help us speed up the process of configuration management using Ansible or Orchestration and Terraform.

  • How does this speed up the process?

  • By creating a script whether it a YML file using Ansible

  • YAML - another Mark up language

Ansible vm/controller

Two Virtual Machines/ Instances: Web and DB

  • What are the Dependencies of these two instances:

  • Web << SSH >>

    • Python (Already installed on Linux version Ubuntu 16.04)

  • DB << SSH >>

    • Python (Already installed on Linux version Ubuntu 16.04)

  • What is Ansible?

  • Automation tool for configuration management

    • Why use Ansible?
      • Simple
      • Agentless - (this means it can connect to different software's and servers even if it hasn't got ansible installed on it.)
      • IT automation Tool
      • Relates simplicity (SSH) Best Configuration tool in the industry for DevOps.
    • The Ansible only needs to be on the controller it does not have to be installed inside any of the instances, and as long as it has a connection with SSH it can configure and update configurations within these instances. So SSH Key is needed.

  • How does it benefit DevOps?

  • Save time

  • Open source

  • Makes configuring management predictable (Cost Effective)

  • It automates the process (configuration management easy)

What is the Hybrid cloud?

  • This is when multiple instances are being hosted in multiple locations such as one on AWS, Azure or local and these can all be configured together using Ansible to skip the process of having to log into the instance and change stuff manually.

Steps we are taking

  • mkdir Ansible
  • cd into Ansible
  • Nano Vagrant File -> Paste in contents
  • Nano README.md
  • Create GitHub and link it
  • Run Vagrant Up
  • Go into each VM with vagrant SSH and run sudo apt-get update

Now we want to make the controller nicknamed AWS into our Ansible Controller agent. The AWS is actually on Premise meaning it is on the companies servers, but AWS was just the name we gave it.

  • TO DO

    • Install ansible onto controller
    • Look at file system of ansible (how it works, files and directories ECT.)
    • How to make host entries (tell controller which Ips to communicate with)
    • Configure the instance so we can ping the other instance and get a response.

  • sudo apt-get install software-properties-common -y get dependencies for ansible

  • sudo apt-add-repository ppa:ansible/ansible this gets the package from the ansible repository. Then run another sudo apt-get update -y.

  • Now you have the package use sudo apt-get install ansible -y

  • Now check if you have it installed with ansible --verison

  • Install tree sudo apt-get install tree (tree is a package manager)

  • Ansible default location is cd /etc/ansible.

Ansible Commands

  • ansible name-vm -m ping to ping another server. -m stands for module. You can use this to test connection between this controller and the target hosts/ VMs.
  • We pinged to two host Ips which were in the vagrant file and got replies on both.
  • ssh vagrant@web and ssh vagrant@db gave no response now we need to add them to the hosts file.
  • Now we go into the hosts file and added our app and db VMs:

[web] 192.168.33.10 ansible_connection=ssh ansible_ssh_user=vagrant ansible_ssh_pass=vagrant

[db] 192.168.33.11 ansible_connection=ssh ansible_ssh_user=vagrant ansible_ssh_pass=vagrant

This one is the Ansible server so it is commented out

[aws] 192.168.33.12 ansible_connection=ssh ansible_ssh_user=vagrant ansible_ssh_pass=vagrant

  • Now we are able to SSH into the App and DB using SSH like so, and entering Vagrant as the password.

  • ssh vagrant@192.168.33.10 For Web

  • ssh vagrant@192.168.33.10 For DB

  • Doing those last two commands creates a connection between the Controller and its hosts when you run the ansible all -m ping command.

Now we pinged all the VMs and got a response saying SUCCESS.

This is the output

This is what it looked like when I pinged the two newly added hosts DB and WebApp

We are going to automate this process soon.

Ad-hoc commands

What are ad-hoc commands? When, How and why do we use them... Some information on Documentation

What

They are one line commands, they have been used in the past.

Why

Allow us to run small commands to any servers in the hosts file and able to retrieve data quickly and efficiently. For example the time in the country or space left on the server.

FAST, ROBUST, FLEXIBLE and EASY

Command List

# Get time
ansible web -a "date"

# Get Machine name, E.G. version running (last -a) means all
ansible db -a "uname -a"

# Get version on own
ansible db -a "uname"

# Go into every server on our hosts and run `ls -a`
ansible all -m shell -a "ls -a"

# Go into every server and see what free space is left
ansible all -m shell -a "free"

Now we are tasked with researching through the ad-hoc documentation

Trying out new commands and reporting back after 10 minutes

# I discoverd a command that returns useful variables from a host
ansible all -m setup

# Gain a list of available modules using
ansible-doc l

# Get up-time of servers
ansible all -m shell -a "uptime"

# Show all environment variables
ansible all -m shell -a "env"

# Copy over files into DB and APP Instances
sudo ansible all -m copy -a "src=test-file.txt dest=/home/vagrant"

# Get ip address of hosts
ansible all -m shell -a "var=hostvars[inventory_hostname]['ansible_default_ipv4']['address']"

ansible db -m shell -a "hostname -i"

# Find disk space inside the VMs
ansible all -m shell -a "free"

Good Site

ansible playbooks

  • What are they? - They are YAML files with .yml extensions
  • Why should we use them/ benefits _ For Configuration management and to install programs or update programs
  • How to create a playbook
  • What can we do with a playbooks? Automates tasks in multiple servers.
  • playbooks are writing in YAML or YML
  • YAML syntax - YAML file starts with --- three dashes
  • YAML works on indentation like python

We created a playbook inside the ansible folder and then we ran it.

First.. we creat the playbook using YAML like so:

# Create playbook file
nano install_nginx_on_web.yml
# This is a YAML file to install NGINX in our web server (A Playbook)
---  # The --- makes this recognised as a yaml file

# Where we are going to install NGINX
- hosts: web

# get the facts
  gather_facts: yes

# work from root user (Permissions)
  become: true

# What do we want ansible to do for us in this playbook

  tasks:
  - name: Install nginx

    # Telling ansible which package to install and the state of it.
    # States : Present / Absent
    apt: pkg=nginx state=present
ansible-playbook <name>

This is now running in the browser on the default port that comes with NGINX, we are now to update it like we have before with all the previous provisioning.

We have been set this exercise