Terraform

Description:

• has some feature of imperative: loop, dynamic, locals,…
• Top to bottom, need to performs the dependencies first
•  An execution plan describing what it will do to reach the desired state, and then executes it to build the described infrastructure.
• As the configuration changes, Terraform can determine what changed and create incremental execution plans that can be applied.
  • based on Terraform State
• Terraform lifecycle: Code → init → plan → validate → apply → destroy
• Files
  • terraform.tfvars or *.vars
  • terraform.tfstate
  • .terraform.tfstate.lock.info
  • .terraform.lock.hcl
  • .terraformignore
    • similar to .gitignore
• Drifts:
  • terraform apply -replace
  • terraform import
  • terraform apply/terraform plan -refresh-only
• Types of errors:
  • language
  • state
  • core
  • provider
• Registry
• Best practices
• Docs

Introduction:

What is Terraform:

• Declarative Programming for Infrastructure management from low-level to high-level resources
• How does terraform work:
• Terraform goes through Terraform Provider which talks to target API of that cloud/service
  • 
• Workflow:
  • Write: define resources, can be multi cloud
  • Plan: to create execution plan, including create/update/destroy
  • Apply

Use cases

• Multi-Cloud Deployment
• Application Infrastructure Deployment, Scaling, and Monitoring Tools
• Self-service clusters: lets product teams manage their own infrastructure independently
• Policy Compliance and Management
• PaaS Application Setup
• Software Defined Networking
• Kubernetes
• Parallel Environments
• Software demos

Terraform vs alternatives

• …

Phases of terraform adoption

• …

Manage infrastructure

Terraform Language

Terraform CLI

Terraform CDK

Collaborate:

HCP Terraform

Develop and Share

Plugin development

• How Terraform works with plugins
  • Terraform Core:
    • written in Go Language
    • responsibilities:
      • Infrastructure as code
      • Resource state management
      • Construction of the Terraform Resource Graph
      • Plan execution
      • Communication with plugins over RPC
  • Terraform Plugin:
    • Invoked by Terraform Core
    • Each plugin exposes an implementation for a specific service, such as AWS, or provisioner, such as bash.
    • All Terraform Provisioners and Terraform Provisioners used in Terraform configurations are plugins
    • responsibilities of Provider Plugins are:
      • Initialization of any included libraries used to make API calls
      • Authentication with the Infrastructure Provider
      • Define managed resources and data sources that map to specific services
      • Define functions that enable or simplify computational logic for practitioner configurations

Modules