# Supported Environments

Supported environments and operational requirements for upstream Kubernetes (MKS) on bare metal and VMs.

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## Operating Systems

| Operating System | Control plane | Worker nodes |
| --- | --- | --- |
| AlmaLinux 9 (64-bit) | Yes | Yes |
| RHEL 8.x (64-bit) | Yes | Yes |
| RHEL 9.1 and 9.2 (64-bit) | Yes | Yes |
| RHEL 10 (64-bit) | Yes | Yes |
| Rocky Linux 9 (64-bit) | Yes | Yes |
| Ubuntu 20.04 LTS (64-bit) (EOL) | Yes | Yes |
| Ubuntu 22.04 LTS (64-bit) | Yes | Yes |
| Ubuntu 24.04 LTS (64-bit) | Yes | Yes |
| Windows Server 2019 (64-bit) | No | Yes |
| Windows Server 2022 (64-bit) | No | Yes |
| Flatcar Linux 4081 | Yes | Yes |

**RHEL kernel**  
On RHEL-based systems, kernel 4.18 is not supported with Kubernetes 1.33 and above. Kernel 4.19 is the recommended 4.x LTS option; 5.x and 6.x kernels are preferred for Kubernetes 1.33+.

**Windows workers**  
Windows worker nodes require Kubernetes v1.23.x or higher and the Calico CNI. Canal and Cilium are not supported with Windows workers.

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## Hypervisors

MKS on VMs is hypervisor-agnostic. The following have been validated for provisioning and lifecycle management:

- VMware vSphere (v7.x, v8.x)
- Microsoft Hyper-V
- Nutanix AOS (v6.5.x LTS, v6.8.x)
- OpenStack (2023.1 Antelope, 2023.2 Bobcat, 2024.1 Caracal)
- VirtualBox (v7.0.x, v6.1.x)

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## Kubernetes versions

Rafay supports four minor Kubernetes versions at a time. When a new minor version is added, the oldest supported minor version is removed. Upgrade clusters regularly to stay on supported versions.

### Supported minor versions

| Version | End of standard support | Added in controller release |
| --- | --- | --- |
| v1.36.x | N/A | v4.1 Update 7 |
| v1.35.x | 25 Feb 2027 | v4.0 Update 4 |
| v1.34.x | 27 Oct 2026 | v3.7 |
| v1.33.x | 28 Jun 2026 | v3.5 |
| v1.32.x (deprecated) | 28 Feb 2026 | v3.1 |
| v1.31.x (EOL) | 28 Oct 2025 | v2.10 |
| v1.30.x (EOL) | 28 Jun 2025 | v2.7 |
| v1.29.x (EOL) | 28 Feb 2025 | v2.4 |
| v1.28.x (EOL) | 28 Oct 2024 | v2.0 |
| v1.27.x (EOL) | 28 Jun 2024 | v1.27 |
| v1.26.x (EOL) | 28 Feb 2024 | v1.25 |
| v1.25.x (EOL) | 27 Oct 2023 | v1.19 |
| v1.24.x (EOL) | 28 Jul 2023 | v1.15 |
| v1.23.x (EOL) | 28 Feb 2023 | v1.11 |

**Note**  
Kubernetes 1.32.x reaches upstream end of life on 28 Feb 2026. Rafay will continue to support it for a transition period so customers can migrate to a supported minor version.

### Patch versions

Default patches are shown in the UI when provisioning or upgrading. Deprecated patches are labeled `(deprecated)` and appear when `Show deprecated Kubernetes patch versions` is enabled.

| Minor | Default patch | Deprecated patches |
| --- | --- | --- |
| v1.36 | v1.36.0 | — |
| v1.35 | v1.35.4 | v1.35.0 |
| v1.34 | v1.34.7 | v1.34.3, v1.34.1 |
| v1.33 | v1.33.11 | v1.33.7, v1.33.5 |
| v1.32 | — | v1.32.13, v1.32.11, v1.32.9 |

Use the default patch for each minor version (for example, v1.35.4 for 1.35). Deprecated patches are for migration and upgrade testing only.

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## Platform versioning

Each platform version bundles cluster components (CRI, etcd, agents) for consistent upgrades. Platform version v1.3.0 is the latest and the default for new cluster creation.

### Component versions

| Component | v1.3.0 (latest) | v1.2.0 | v1.1.0 (deprecated) |
| --- | --- | --- | --- |
| CRI | 2.3.0 | 2.0.4 | 2.0.4 |
| etcd | 3.5.24 | 3.5.24 | 3.5.21 |
| Cluster Utils | 2.0.0 | 2.0.0 | 2.0.0 |
| Orchestration Agent | 3006.12 | 3006.12 | 3006.12 |
| Orchestration Proxy | 1.10.1 | 1.10.1 | 1.10.1 |

### Platform version summary

| Version | Status | Notes |
| --- | --- | --- |
| v1.3.0 | Latest (default) | Default for new cluster creation; required for Kubernetes v1.36. CRI 2.3.0 is the minimum containerd version for v1.36. |
| v1.2.0 | Active | Required for Kubernetes v1.35 and default patches v1.35.4, v1.34.7, v1.33.11. etcd 3.5.24 is required for Kubernetes 1.35+. |
| v1.1.0 | Deprecated | Migration only. See component table above. |
| v1.0.0 | Deprecated | Migration only. |
| v0.1.0 | Deprecated | Reference label for clusters created before platform versioning. Upgrade to v1.2.0 (direct upgrade from v0.1.0 is supported). |

Deprecated platform versions (v1.1.0, v1.0.0, v0.1.0) are labeled `(deprecated)` in the UI. Enable `Show deprecated platform versions` to select them.

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## Node management and cluster upgrades

### Prerequisites

- Control plane: 8 OCPUs (16 vCPUs), 32 GB memory
- Workers: 1 OCPU (2 vCPUs), 4 GB memory

### Recommendations

- Add or remove nodes in batches of up to 100
- If some nodes fail during upgrade, the retry mechanism upgrades the remainder

**Important**  
Qualified for up to 500 nodes and 10,000 pods.

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## Container networking (CNI)

| CNI | Notes |
| --- | --- |
| Cilium | Recommended for Linux nodes |
| Calico | Recommended for Linux and Windows nodes |
| Canal | Calico + Flannel |
| Flannel | Deprecated; not recommended for new clusters |

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## CPU, memory, and architecture

- Control plane: Linux/x64 and Linux/arm64
- Workers: Linux/x64, Linux/arm64, or Windows/x64
- Full ARM support on Ubuntu 22.04 and 24.04 LTS (default and default-upstream blueprints)

### Minimal blueprint

| Resource | Minimum |
| --- | --- |
| vCPUs per node | 2 |
| Memory per node | 4 GB |

### default-upstream blueprint

Single-node cluster:

| Resource | Minimum | Cores |
| --- | --- | --- |
| vCPUs per node | 2 | 4 |
| Memory per node | 16 GB | — |

HA cluster:

| Resource | Minimum | Cores |
| --- | --- | --- |
| vCPUs per node | 2 | 4 |
| Memory per node | 16 GB | — |

**Important**  
Allow extra capacity if you deploy blueprints with monitoring, storage, or other add-ons. To switch from default-upstream to another blueprint after provisioning, delete workload deployments and workload PVCs first.

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## GPU

NVIDIA GPUs compatible with Kubernetes are supported. See [GPU overview](https://docs.rafay.co/recipes/gpu/overview/).

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## Container runtime

Clusters use containerd (CRI) instead of Dockershim (removed from Kubernetes 1.20+). In-place Kubernetes upgrades also move nodes to containerd; plan for workload restarts.

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## Inter-node networking

Multi-node clusters require node-to-node connectivity across all UDP/TCP ports.

### Control plane

| Protocol | Direction | Ports | Purpose |
| --- | --- | --- | --- |
| TCP | Inbound | 6443 | API server |
| TCP | Inbound | 2379-2380 | etcd |
| TCP | Inbound | 10250, 10255 | kubelet |
| TCP | Inbound | 10259, 10251 | scheduler |
| TCP | Inbound | 10257, 10252 | controller-manager |
| UDP | Inbound | 8285 | Flannel |
| TCP | Inbound | 30000-32767 | NodePort (if exposed on control plane) |
| TCP | Inbound | 9099 | Calico |
| TCP | Inbound | 5656 | OpenEBS Local PV |
| UDP | Inbound | 4789 | VXLAN |

### Workers

| Protocol | Direction | Ports | Purpose |
| --- | --- | --- | --- |
| TCP | Inbound | 10250, 10255 | kubelet |
| TCP | Inbound | 30000-32767 | NodePort |
| UDP | Inbound | 8285, 8472 | Flannel |
| TCP | Inbound | 8500 | Consul |
| UDP | Inbound | 8600 | Consul |
| TCP/UDP | Inbound | 8301 | Consul |
| TCP | Inbound | 9099 | Calico |
| TCP | Inbound | 5656 | OpenEBS Local PV |
| UDP | Inbound | 4789 | VXLAN |

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## Forward proxy

Configure when nodes cannot reach the controller directly and must use a non-transparent proxy.

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## Storage

Turnkey storage options in the cluster blueprint simplify [PersistentVolume](https://kubernetes.io/docs/concepts/storage/persistent-volumes/) management on bare metal and VMs.

### Local PV

Required storage class.

- [OpenEBS](https://openebs.io/) on bare metal and VMs
- [Amazon EBS](https://aws.amazon.com/ebs/) on EC2 (requires IAM role for dynamic provisioning)

Suited for: workloads with built-in replication (MongoDB, Redis, Cassandra, Postgres), high local throughput, or single-node/edge clusters without shared storage.

### Distributed storage

Optional [Rook-Ceph](https://rook.io/) for highly available shared storage and pod rescheduling across workers.

**Important**  
GlusterFS-based managed storage was deprecated in Q1 2022 and EOL in Q1 2023.

### Storage requirements
#### Root disk

Used for container images, Kubernetes binaries, etcd, Consul, system packages, and logs (rotated via logrotate).

- Raw, unformatted
- Minimum 50 GB; recommended 100 GB+

**Note**  
On a single-node cluster, reserve about 30 GB for platform data and 20 GB for workload PVCs unless you plan additional capacity.

#### Secondary disk

Optional; required only for Rook-Ceph. Dedicated to workload PVCs.

- Raw, unformatted
- Minimum 50 GB per node; recommended 100 GB+

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