Kubernetes Clusters - Upstream (eg...kubeadm) Vs Downstream(eg..eks) | Overview.

Kubernetes Clusters - Upstream (eg...kubeadm) Vs Downstream (eg..eks) - Overview.

Scope:

• Intro,
• Upstream Kubernetes (eg kubeadm),
• Downstream Kubernetes (eg eks),
• What It Means,
• Characteristics,
• Examples,
• Comparison Table,
• When to Use Upstream Kubernetes (eg kubeadm, kind, kops),
• When to Use  Downstream Kubernetes (eg eks),
• Real-world examples of upstream and downstream Kubernetes clusters,
• Visualization of Code Flow,
• Summary.

Intro:

• The terms "upstream" and "downstream" in the context of Kubernetes clusters often refer to the direction of code flow, contributions, and customization of the cluster.
• Here's twtech Overview.

 Kubernetes Clusters – Upstream vs Downstream

 Upstream Kubernetes

 What It Means:

•         The official Kubernetes project maintained by the Cloud Native Computing Foundation (CNCF).
•        Source of truth: https://github.com/kubernetes/kubernetes
•         It’s the pure, open-source version without vendor modifications.

Characteristics:

•         Community-developed and maintained.
•         Vendor-neutral, portable across environments.
•         Releases, features, and bug fixes originate here.

 Example Use:

•         Building a custom Kubernetes distribution.
•         Running a lab or sandbox cluster using tools like kubeadm, kind, kops or minikube.

 Downstream Kubernetes

What It Means:

•         A modified or curated version of upstream Kubernetes provided by vendors.
•         Adds features, integrations, or enterprise support.

 Characteristics:

•         May include:
•    Custom dashboards
•    Security patches
•    Better cloud integrations
•    Proprietary extensions or operators
•         Follows upstream releases but may lag behind slightly.
•         May remove or restrict certain upstream features for stability or policy.

 Examples:

•         Amazon EKS (AWS's downstream distro of Kubernetes)
•         Red Hat OpenShift (based on upstream, but heavily customized)
•         Rancher Kubernetes Engine (RKE)

 Comparison Table

Feature	Upstream Kubernetes	Downstream Kubernetes (Vendor)
Source.	CNCF / Community	Based on upstream
Customization.	Raw Kubernetes	Vendor-specific
Support.	Community-driven	Enterprise support available
Release Cadence.	Rapid	May lag for stability/testing
Integrations.	Manual	Built-in (IAM, networking, etc)
Ideal For.	Custom builds, research, labs	Production, enterprise, managed

When to Use Each

twtech Uses Upstream Kubernetes if: Like kubeadm

•         twtech wants full control.
•         twtech is contributing to Kubernetes.
•         twtech is building a custom Kubernetes distribution.

twtech Uses Downstream Kubernetes if:  Like EKS

•         twtech wants a ready-to-use, production-ready, or managed solution.
•         twtech needs enterprise support, integrated logging, monitoring, or security.
•         twtech want to minimize operational overhead.

twtech Insights

• Here are real-world examples of upstream and downstream Kubernetes clusters, to help twtech clearly understand the distinction:

 Upstream Kubernetes Clusters (Open Source / Community-Based)

• These clusters run the vanilla, unmodified version of Kubernetes from the CNCF:

Example of Upstream Kubernetes Clusters	Description
kubeadm	Tool provided by the Kubernetes project to install and bootstrap upstream clusters. Used in self-hosted or lab environments.
kind	“Kubernetes IN Docker” – used for local development/testing using upstream Kubernetes.
minikube	Local, lightweight upstream Kubernetes cluster for development or learning.
k3s (by Rancher)	Lightweight upstream-compatible Kubernetes distro optimized for edge/IoT.
bare-metal clusters using upstream tarballs	Direct installs using official Kubernetes releases and binaries from GitHub.

 Downstream Kubernetes Clusters (Vendor-Modified / Managed)

• These are vendor-distributed or managed Kubernetes clusters that are based on (but often extend) upstream Kubernetes:

Example of downstream Kubernetes Vendor Cluster	Description
Amazon EKS	AWS-managed Kubernetes with VPC, IAM, Fargate, and CloudWatch integration.
Google Kubernetes Engine (GKE).	GCP-managed Kubernetes with tight integration into Google Cloud services.
Red Hat OpenShift.	Enterprise Kubernetes built on upstream but with added CI/CD, security, and operator lifecycle management.
VMware Tanzu Kubernetes Grid.	VMware’s enterprise Kubernetes distribution, tailored for vSphere and multi-cloud.
Rancher (RKE, RKE2).	Rancher-managed Kubernetes clusters that simplify and harden upstream Kubernetes.
Canonical Kubernetes (Charmed Kubernetes).	Downstream distro with additional automation and enterprise support from Canonical (Ubuntu).

 Visualization of Code Flow

twtech-Summary

Type	Examples	Use Case
Upstream.	kubeadm, kind,kops.	Test, development, research
Downstream.	EKS, OpenShift, Rancher.	Production, enterprise, cloud