Ansible Note

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Note for learning Ansible

Background

IaC - Infrastructure as Code

Definition:

  • Use the “code” which can be executed by software to present the IT system infrastructure state.
  • The system infrastructure will contain middle software deployment, external service, and the cooperation with provision. (Not only Machine and Network)

Benefit:

  • Reduce man power to lower the cost.
  • Use programization to reach the high quality
  • Easily to deploy large scale.

DevOps

Definition:

  • Use the close cooperation between Dev (Development) and Ops (Oprations) to shorten the software life cycle.
  • For IaC, we can briefly summarize that it is use code to define a state or operation.
  • Design rule:
    • Use sub-version tool (Git) to do the version control
    • Automation tool test
      • static test with code analysis
      • Asible to test enviroment
      • Serverspec to test the machine state
  • Use tool to do CI (Continous Integration)
    • Use Jenkin to deploy, and then automatically start Ansible to react to real environment
    • Co-work with git to synchonize code and deployment immediately.

For sure, IaC can make all the design procedure automatical.

Note : shell script is also an example of IaC, but only for some low effort work. Chef, Puppet, and Ansible are also example.

Ansible

  • Created by Red Hat,
  • Use Python to state and promote automation for everyone.
  • Component:
    • Ansible
      • when launching a moddule or playbook, use CLI to execute Ansible. After that, we can use all the command after installation by Ansible.
    • Inventory [Where do you want to deploy with Ansible]
      • the machine list you want to deploy
      • group the machine you want to deploy, and can set different parameters for each group
    • Module [What do you want to do with Ansible]
      • The function that use Ansible to execute.
        • OS operation (package installation, update etc)
        • file operation (File copy and paste)
        • DB operation (MYSQL, Postgresql etc)
        • Cloud service operation (AWS, OpenStack etc)
        • online machine operation
      • Different from normal command, Ansible will check the statement at this timing, and do only the part we have changed. It will be very complex if you use shell.
      • ansible-doc -l to check the module that Ansible
    • Playbook []
      • A rundown code to Ansible.
      • Different from other automation tool, the statement description of the playbook is not a programming language.
      • Use Yaml to state, which just a modification from JSON.
      • Yaml is easy to read from both people and machines.