diff --git a/tech_docs/Infrastructure-as-Files.md b/tech_docs/Infrastructure-as-Files.md new file mode 100644 index 0000000..081a574 --- /dev/null +++ b/tech_docs/Infrastructure-as-Files.md @@ -0,0 +1,101 @@ +You're absolutely right to call out loose terminology—this space is full of overloaded terms, and I should be more precise. Let’s tighten this up with **rigorous definitions** and clarify where tools like Kubernetes and Ansible fit. + +--- + +### **1. Strict Definitions** +#### **Infrastructure-as-Files (IaF)** +- **What it is**: + - **Static, declarative files** (YAML, JSON, HCL) that describe desired state. + - **No logic** (no loops, conditionals, or dynamic generation). + - **Manual/scripted application** (e.g., `kubectl apply -f`, `ansible-playbook`). + - **No state management** (applying files doesn’t track drift). + +- **Examples**: + - Kubernetes manifests (`deployment.yaml`). + - Ansible playbooks (if purely declarative). + - Terraform `*.tf` files (if no dynamic blocks/modules). + +#### **Infrastructure-as-Code (IaC)** +- **What it is**: + - **Programmatic** (Terraform, Pulumi, CDK) with logic (loops, conditionals, functions). + - **Stateful** (tracks actual vs. desired state, e.g., Terraform state files). + - **Automated workflows** (plan/apply, drift detection). + +- **Key difference**: + - IaC **generates** infrastructure definitions dynamically; IaF **is** the definition. + +#### **GitOps** +- **What it is**: + - A **methodology** where Git is the source of truth, and changes are **automatically applied** (e.g., ArgoCD, Flux). + - Can use **IaF or IaC** under the hood (e.g., Kubernetes YAML or Terraform plans). + +--- + +### **2. Clarifying Kubernetes and Ansible** +#### **Kubernetes: IaF by Default, But Can Be IaC/GitOps** +- **Native workflow**: IaF (apply YAML files manually). + ```sh + kubectl apply -f deployment.yaml # Pure IaF + ``` +- **IaC overlay**: Tools like `kustomize` (templating), Helm (logic), or Crossplane (provisioning) add IaC capabilities. +- **GitOps**: ArgoCD watches Git repos and auto-applies YAML (still IaF, but automated). + +#### **Ansible: Hybrid IaF/IaC** +- **IaF mode**: Static playbooks (no dynamic logic). + ```yaml + # playbook.yml (IaF) + - hosts: webservers + tasks: + - name: Install nginx + apt: name=nginx state=present + ``` +- **IaC mode**: When using Jinja2 templating, loops, or dynamic inventories: + ```yaml + # IaC-like (dynamic) + - name: Install packages + apt: "name={{ item }} state=present" + loop: "{{ packages }}" + ``` + +--- + +### **3. Why the Confusion?** +- **Overlap**: Many tools support both modes (e.g., Ansible can be IaF or IaC). +- **Marketing**: Vendors blur terms (e.g., calling Helm "IaC" when it’s templated IaF). +- **Evolution**: GitOps emerged as a pattern atop IaF/IaC. + +--- + +### **4. Decision Tree: Is It IaF or IaC?** +| **Tool/File** | **IaF?** | **IaC?** | **Notes** | +|----------------------|----------|----------|-----------| +| Kubernetes YAML | ✅ Yes | ❌ No | Unless templated (Helm/Kustomize). | +| Terraform `*.tf` | ❌ No | ✅ Yes | Dynamic blocks/modules make it IaC. | +| Ansible (static) | ✅ Yes | ❌ No | Pure YAML playbooks. | +| Ansible (dynamic) | ❌ No | ✅ Yes | Uses Jinja2/loops. | +| Docker Compose | ✅ Yes | ❌ No | Static YAML. | +| Pulumi (Python/TS) | ❌ No | ✅ Yes | Full programming model. | + +--- + +### **5. Key Takeaways** +1. **IaF** = Static files, no logic, manual apply. + - Example: Raw Kubernetes YAML, basic Ansible playbooks. +2. **IaC** = Code (logic, state, automation). + - Example: Terraform, Pulumi, dynamic Ansible. +3. **GitOps** = Automation layer atop IaF/IaC. + - Example: ArgoCD syncing Kubernetes YAML from Git. + +--- + +### **6. Fixing My Earlier Mistakes** +- **Kubernetes**: Default is IaF, but **not all Kubernetes workflows are IaF** (Helm/Kustomize add IaC-like features). +- **Ansible**: Can be **IaF or IaC** depending on use. +- **GitOps ≠ IaF**: GitOps automates IaF/IaC; they’re orthogonal concepts. + +--- + +### **Final Answer** +**IaF is a subset of IaC tooling**—it’s the "dumb YAML" layer. When you add logic/automation, it becomes IaC or GitOps. Kubernetes and Ansible **default to IaF** but can cross into IaC territory with advanced features. + +Would you like concrete examples (e.g., "Here’s how the same app is defined in IaF vs. IaC")? I’m happy to dive deeper. \ No newline at end of file