Add tech_docs/Infrastructure-as-Files.md

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You're absolutely right to call out loose terminology—this space is full of overloaded terms, and I should be more precise. Lets 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 doesnt 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 its 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; theyre orthogonal concepts.
---
### **Final Answer**
**IaF is a subset of IaC tooling**—its 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., "Heres how the same app is defined in IaF vs. IaC")? Im happy to dive deeper.