Select k3d as the primary solution for running Kubernetes clusters on Windows and macOS, alongside native k3s on Linux, to achieve a consistent "zero setup" experience across platforms while considering resource usage, complexity, and long-term alternatives like WebAssembly.
		
			
				
	
	
		
			66 lines
		
	
	
		
			2.6 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
			
		
		
	
	
			66 lines
		
	
	
		
			2.6 KiB
		
	
	
	
		
			Markdown
		
	
	
	
	
	
## Architecture Decision Record: Default Runtime for Managed Workloads
 | 
						|
 | 
						|
### Status
 | 
						|
 | 
						|
Proposed
 | 
						|
 | 
						|
### Context
 | 
						|
 | 
						|
Our infrastructure orchestrator manages workloads requiring a Kubernetes-compatible runtime environment.
 | 
						|
 | 
						|
**Requirements**
 | 
						|
 | 
						|
- Cross-platform (Linux, Windows, macOS)
 | 
						|
- Kubernetes compatibility
 | 
						|
- Lightweight, easy setup with minimal dependencies
 | 
						|
- Clean host teardown and minimal residue
 | 
						|
- Well-maintained and actively supported
 | 
						|
 | 
						|
### Decision
 | 
						|
 | 
						|
We select **k3d (k3s in Docker)** as our default runtime environment across all supported platforms (Linux, Windows, macOS).
 | 
						|
 | 
						|
### Rationale
 | 
						|
 | 
						|
- **Consistency Across Platforms:**  
 | 
						|
  One solution for all platforms simplifies development, supports documentation, and reduces complexity.
 | 
						|
 | 
						|
- **Simplified Setup and Teardown:**  
 | 
						|
  k3d runs Kubernetes clusters in Docker containers, allowing quick setup, teardown, and minimal host residue.
 | 
						|
 | 
						|
- **Leveraging Existing Container Ecosystem:**  
 | 
						|
  Docker/container runtimes are widely adopted, making their presence and familiarity common among users.
 | 
						|
 | 
						|
- **Kubernetes Compatibility:**  
 | 
						|
  k3s (within k3d) is fully Kubernetes-certified, ensuring compatibility with standard Kubernetes tools and manifests.
 | 
						|
 | 
						|
- **Active Maintenance and Community:**  
 | 
						|
  k3d and k3s both have active communities and are well-maintained.
 | 
						|
 | 
						|
### Consequences
 | 
						|
 | 
						|
#### Positive
 | 
						|
 | 
						|
- **Uniform User Experience:** Users have a consistent setup experience across all platforms.
 | 
						|
- **Reduced Support Overhead:** Standardizing runtime simplifies support, documentation, and troubleshooting.
 | 
						|
- **Clean Isolation:** Containerization allows developers to easily clean up clusters without affecting host systems.
 | 
						|
- **Facilitates Multi-Cluster Development:** Easy creation and management of multiple clusters concurrently.
 | 
						|
 | 
						|
#### Negative
 | 
						|
 | 
						|
- **Docker Dependency:** Requires Docker (or compatible runtime) on all platforms.
 | 
						|
- **Potential Overhead:** Slight performance/resource overhead compared to native k3s.
 | 
						|
- **Docker Licensing Considerations:** Enterprise licensing of Docker Desktop could introduce additional considerations.
 | 
						|
 | 
						|
### Alternatives Considered
 | 
						|
 | 
						|
- **Native k3s (Linux) / k3d (Windows/macOS):** Original proposal. Rejected for greater simplicity and consistency.
 | 
						|
- **Minikube, MicroK8s, Kind:** Rejected due to complexity, resource usage, or narrower use-case focus.
 | 
						|
- **Docker Compose, Podman Desktop:** Rejected due to lack of orchestration or current limited k3d compatibility.
 | 
						|
 | 
						|
### Future Work
 | 
						|
 | 
						|
- Evaluate Podman Desktop or other container runtimes to avoid Docker dependency.
 | 
						|
- Continuously monitor k3d maturity and stability.
 | 
						|
- Investigate WebAssembly (WASM) runtimes as emerging alternatives for containerized workloads.
 |