adam's notes

Infrastructure as Code (IaC)

Infrastructure as Code (IaC) is a provisioning architecture in which deployment of resources is performed by scripted automation and orchestration.

  • manages computing infrastructure using machine-readable definition files
    • files are written in formats like YAML, JSON, and HCL (HashiCorp Configuration Language)
    • contain information about the desired infrastructure state
      • e.g., configuration settings, networking requirements, security policies, and other settings
    • infrastructure can be deployed and managed automatically and consistently
      • reduce risk of errors
    • files are typically version-controlled
    • can also easily replicate infrastructure across different environments
      • e.g., development, staging, production
  • goals
    • eliminate snowflake systems
      • is a configuration or build that is different from any other
      • lack of consistency (drift) in platform environment leads to security issues
        • e.g., missed patches, stability issues, failing scripts
  • deployed to provision immutable architecture
    • instances are never updated in place
    • instead, a new instance is deployed to replace the old one
    • ensures idempotence
      • making the same call with the same parameters will always produce the same result
      • by rejecting manual configuration and ad hoc patching
  • uses for infrastructure as code

Info

  • IaC is not simply a matter of using scripts to perform repetitive tasks
    • Running scripts that have been written ad hoc is just as likely to cause environment drift as manual configuration
    • IaC means using carefully developed and tested scripts and orchestration playbooks to generate consistent builds

Info

HCL (HashiCorp Configuration Language) is a configuration language developed by HashiCorp and used in Infrastructure as Code (IaC) environments to manage and provision computing infrastructure.

  • is similar to JSON and YAML in terms of syntax,
    • but it has some additional features that make it more suitable for infrastructure management
    • supports variables inside configuration files
    • has a concise syntax that makes it easy to read and write
  • HCL is used in many popular HashiCorp tools, including Terraform and Consul.

Automation and Playbooks

Automation is using scripts and APIs to provision and deprovision systems without manual intervention.

  • manual configuration follows a standard operating procedure (SOP)
  • script takes standard arguments as data
    • less scope for uncertainty over configuration choices leading to errors
    • ensures systems are in compliance with network or security policies
  • automation playbook
    • aim is to script as much of SOP as possible
      • leave clearly defined interaction points for human intervention and verification
  • two types of automation tools:
    • imperative tools
      • take the precise series of steps required to achieve the desired configuration as input
    • declarative tools
      • take the desired configuration as input and leave the detail of how that configuration should be achieved to the implementation platform

Orchestration

Orchestration is automation of multiple coordinated steps in a deployment process.

  • performs a sequence of automated tasks
    • automation focuses on a single task
  • e.g., orchestrate adding a VM to a load-balanced cluster
    • includes:
      • provisioning VM
      • configuring it with app and network settings
      • adding VM to load-balanced cluster
      • reconfigure load-balancing weight distribution
  • automated steps must occur in corrected sequence
    • take dependencies into account
    • must have correct security credentials and permissions
  • used to provide administration, management, and orchestration of CSPs
  • advantage of 3rd-party orchestration platform:

Graph View

Backlinks