DevOps Classroom Series – 09/Mar/2020

Configuration Managment Solution Workflow

• Purpose: Automate Deployments, or to be very specific
  • ensuring the code written by dev team is reflected in one or more of the enviroments
• Knowledge:
  • Various Environments available
  • When to deploy in each environment
  • Pre-requisites to deploy application. Some of examples are
    • JDK 1.9 and tomcat 9 are required
    • Python 3.7 is used
    • Ensure /etc/<application>/config.yaml has database servers url, username and password.
  • Steps of deploying
  • Make a list of OS-Level (linux/windows commands) to be exeucted to deploy the application
  • Execute all the commands gathered manually to ensure they are working.

Example:

• Purpose: Create a Dev Environment for Spring-Petclinic
• Knowledge:
  • Env: Dev => 1 linux vm
  • Prereqs:
    • JDK8
  • Steps for deploying
    • There is a package available at here
    • run the spring boot application directly
    • Commands

    sudo apt-get update && sudo apt-get install openjdk-8-jdk -y
    wget https://war-jar-files.s3-us-west-2.amazonaws.com/spring-petclinic-2.2.0.BUILD-SNAPSHOT.jar
    java -jar spring-petclinic-2.2.0.BUILD-SNAPSHOT.jar
    

Ansible Way of Working

• In Ansible smallest activity (atomic) is called as module
• For linux commands which you have written find the right modules in ansible. Ansible has lot of modules Refer Here
• We will be creating one-one mapping between linux commands and modules to be used

Linux        Ansible Module
apt-get   =>  apt
wget      =>  get_url
java      =>  command

• Combine modules to form playbook
• Now ansible can be executed in two modes
  • Adhoc Command:
    • To run ansible create a command

    ansible -m ping all
    

  • Playbook:
    • Write a YAML file to automate the deployment
• Sample YAML

---
- hosts: all
  become: yes
  tasks:
    - name: install java and update packages
      apt:
        name: openjdk-8-jdk
        update: yes
        state: present
    - name: download package
      get_url:
        url: https://war-jar-files.s3-us-west-2.amazonaws.com/spring-petclinic-2.2.0.BUILD-SNAPSHOT.jar
    - name: run spring pet clinic
      command: java -jar spring-petclinic-2.2.0.BUILD-SNAPSHOT.jar
        

Ansible Terms

• Playbook: YAML Reprsentation of Automation to be done
• Tasks:
  • Each task will be module to be executed with some parameters
• Module:
  • Atomic unit of automation in Ansible.

Exercise

• Find steps to deploy
  • node js application
  • PHP application.