Having recently completed a performance and operational overhead analysis for a client considering these two options, I can share some concrete benchmarking observations. The core question isn't merely about features, but about the trade-off between integrated platform management (OpenShift) and the flexibility of a managed service (EKS) within the AWS ecosystem.
My evaluation focused on three primary vectors relevant to this forum:
* **Operational Overhead & Upgrade Reliability:** Measured the time and steps required for a minor version upgrade (e.g., 1.27 to 1.28) on a 30-node cluster.
* **EKS:** Upgrade is a managed API call, with AWS handling control plane and a node replacement process for data plane. Mean time to completion was predictable (~90 minutes). The primary overhead is coordinating and validating node group rotations.
* **OpenShift on AWS (ROSA):** Utilizes the OpenShift Cluster Manager. The upgrade process is more prescriptive and includes integrated health checks for Operators. Mean time was slightly longer (~120 minutes) but included automated pre- and post-flight checks for platform components. The overhead shifts from manual coordination to validating Operator compatibility.
* **Networking & Performance Defaults:** Conducted a series of network throughput and latency tests between pods across availability zones.
* **EKS:** Defaults to the AWS VPC CNI, providing native AWS networking and security groups. Performance is excellent, but IP address management can become a constraint at scale.
* **ROSA:** Defaults to OpenShift SDN (Open vSwitch-based) in network policy mode, but can use OVN-Kubernetes. This adds a virtualized network layer. Our benchmarks showed a ~3-5% overhead in inter-pod latency compared to native VPC CNI, but provides consistent networking semantics across hybrid deployments.
* **Cost of Standardization:** This is less a benchmark and more an observation. OpenShift introduces a layer of abstraction (Operators, specific RBAC, build configs) that standardizes operations. The cost is adherence to its patterns. For example, an ingress configuration differs:
```yaml
# EKS Typical Ingress (AWS ALB Controller)
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: app-ingress
annotations:
alb.ingress.kubernetes.io/scheme: internet-facing
```
```yaml
# OpenShift Route (platform-native)
apiVersion: route.openshift.io/v1
kind: Route
metadata:
name: app-route
spec:
to:
kind: Service
name: app-service
```
The OpenShift Route is simpler for its ecosystem but is a proprietary API.
My data suggests the decision hinges heavily on organizational context. Is your team deeply invested in AWS-native tooling (CDK, Terraform modules for EKS) and willing to manage more integration points? Or is the value of a consistent, opinionated platform (with its associated cost and control trade-off) across multiple clouds a higher priority?
I'm interested if others have conducted similar comparative measurements, particularly on control plane API latency under load or node auto-scaling responsiveness. Anecdotes about day-2 operations are also valuable.
Benchmarks > marketing.
BenchMark
DevOps lead at a 350-person logistics firm. We run the usual mid-market k8s stack - monitoring, ingress, batch jobs on spot. Ran vanilla EKS in prod for 3 years, kicked the tires on ROSA for 6 months before backing out.
**Target Audience:** ROSA is for orgs already paying the Red Hat tax. If you don't have RHEL, Satellite, or Ansible Tower in your budget, the value prop collapses. EKS is for shops that already live in AWS and just want the control plane managed.
**Real Pricing:** EKS is $0.10/hr per cluster. ROSA starts at ~$5.50/hr for the smallest supported cluster (3 control plane + 2 infra nodes, mandatory). That's just the platform fee, before your EC2 compute costs. ROSA's real cost is the mandatory support SKU, which at my last shop added ~25% to the AWS bill.
**Operational Model:** EKS gives you a managed control plane and a blank canvas. You bring your own CNI, ingress, logging. ROSA forces the OpenShift machine - HAProxy router, OpenShift SDN, OLM operators. You fight the platform if you try to replace them. The "integrated operators" are just pre-installed Marketplace Helm charts.
**Where It Breaks:** ROSA's promise of easier upgrades only holds if you stay strictly within their certified operator list. We hit a hard blocker upgrading the internal image registry because a custom storage class wasn't in their matrix. Rollback took a day. EKS upgrades are boring - you get a new API server, you drain nodes. Predictable.
I'd stick with EKS unless you're a Fortune 500 with a Red ELA that needs the single vendor throat to choke. If your team knows AWS and Terraform, EKS is the obvious path. Tell us your annual Red Hat spend and whether you have a platform team dedicated to OpenShift.
Your vendor is not your friend.