kubernetes
k3s Resource Calculator
Calculate RAM and CPU requirements for a k3s cluster. k3s has 5–10× lower overhead than full Kubernetes — see exactly how much your server and agent nodes need.
k3s vs Full Kubernetes: Resource Comparison
k3s is a CNCF-certified Kubernetes distribution from Rancher (now SUSE) that packs the entire control plane into a single binary under 100 MB. It's designed for edge computing, IoT, CI/CD, and resource-constrained environments.
Memory Overhead Comparison
| Component | Full K8s | k3s |
|---|---|---|
| API server | ~350 MB | included in server binary |
| etcd | ~400 MB | SQLite or embedded etcd |
| controller-manager | ~150 MB | included |
| scheduler | ~100 MB | included |
| Total server | ~1,500 MB | ~512 MB |
| kubelet (per node) | ~200 MB | ~75 MB (k3s agent) |
What k3s Removes
k3s strips out cloud-provider integrations, in-tree storage drivers, and alpha/beta features. This reduces binary size and memory footprint. Nothing you'd use in a standard deployment is missing.
When to Use k3s
- ›Edge and IoT devices (Raspberry Pi, ARM boards)
- ›CI/CD ephemeral clusters
- ›Single-node home lab or VPS deployments
- ›Small teams without dedicated Kubernetes expertise
- ›Clusters under 50 nodes that don't need enterprise K8s features
When to Use Full Kubernetes
- ›Large clusters (50+ nodes)
- ›Enterprise features (PSP, advanced admission webhooks)
- ›Specific cloud-provider integrations (EKS, GKE managed addons)
- ›Compliance requirements mandating upstream K8s
Frequently Asked Questions
How much RAM does k3s use compared to full Kubernetes?
k3s uses ~512 MB RAM for the server (control plane) vs ~1.5–2 GB for a full kubeadm cluster. k3s agents use ~75 MB vs ~200 MB for a standard kubelet. This makes k3s ideal for edge, IoT, and resource-constrained environments.
What is the minimum server spec for a k3s cluster?
The k3s server can run on 512 MB RAM and 1 vCPU for development. For production with a few agents, use at least 1 GB RAM and 2 vCPU. Agent nodes can run on as little as 256 MB RAM for lightweight workloads.
Can k3s replace full Kubernetes in production?
Yes, for most use cases. k3s runs the same Kubernetes API and supports the same workloads. It uses SQLite by default (vs etcd) for small clusters, but supports embedded etcd for HA setups. Many companies run k3s in production for edge, IoT, and small-scale deployments.
Does k3s support high availability?
Yes. k3s embedded HA uses embedded etcd with 3 server nodes — same quorum model as full Kubernetes. You can also use an external datastore (PostgreSQL, MySQL) for HA. For small clusters (<50 nodes), embedded etcd HA is the recommended approach.
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