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Cloud · head to head

K3s vs containerd

K3s logo

K3s

Cloud

Lightweight certified Kubernetes distribution in a single binary

From
Free
Rated
-
Full reviewWebsite
containerd logo

containerd

Cloud

Industry-standard container runtime, and the engine inside Docker

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: K3s the SQLite default is single-server only; highly available control planes need etcd or an external datastore, which removes much of the simplicity; containerd not a developer-facing tool: there is no build command and the CLI is deliberately minimal, so it needs companions like nerdctl or Buildah
  • They diverge on capability: K3s covers Single binary, containerd covers Full container lifecycle.

Where they differ

Only the attributes on which K3s and containerd actually diverge.

Attributes where K3s and containerd differ
AttributeK3scontainerd
PlatformsLinux, ARM, Self-hostedLinux, Windows

Identical on both: starting price (Free), pricing model (Open source, no licence fee), free tier (Yes), user rating (Not yet rated), category (Cloud).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in K3s

  • Single binary
  • SQLite by default
  • Certified conformant
  • Batteries included
  • Low resource footprint
  • Simple install

Only in containerd

  • Full container lifecycle
  • CRI support
  • OCI compliant
  • Snapshotter plugins
  • Namespaces
  • Stable API

What people use each for

The jobs each tool is most often brought in to do.

K3s

  • Kubernetes on edge sites and IoT hardware where full clusters will not fitnot containerd
  • Development and CI clusters that must start fast and cost nothingnot containerd
  • Small production clusters where full Kubernetes is more operations than the workload justifiesnot containerd
  • Teaching and learning Kubernetes without cloud spendnot containerd

containerd

  • Running the container runtime under a Kubernetes cluster after the Docker shim removalnot K3s
  • Building a platform or PaaS that needs to execute containersnot K3s
  • Reducing the moving parts on nodes that only ever run Kubernetes workloadsnot K3s
  • Embedding container execution inside another productnot K3s

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

K3s

  • The SQLite default is single-server only; highly available control planes need etcd or an external datastore, which removes much of the simplicity
  • Bundled components such as Traefik are opinionated defaults that larger teams often strip out and replace
  • Removed in-tree cloud provider integrations mean cloud-specific features need external controllers
  • Aimed at small and edge clusters, so very large deployments are better served by a standard distribution

containerd

  • Not a developer-facing tool: there is no build command and the CLI is deliberately minimal, so it needs companions like nerdctl or Buildah
  • Debugging is lower-level than Docker, and error messages assume knowledge of the runtime internals
  • Documentation is aimed at platform engineers, so newcomers usually find Docker or Podman material more useful
  • No image building at all — that is out of scope by design

Pricing, plan by plan

K3s

Free
  • K3sFree
    • Full functionality
    • No usage limits
    • Community support

containerd

Free
  • containerdFree
    • Full functionality
    • No usage limits
    • Community support

Which should you pick?

Choose K3s if

  • You need single binary.
  • You want to start without paying.
  • You work on Linux, ARM, Self-hosted.
  • You also want sqlite by default.
K3s review

Choose containerd if

  • You need full container lifecycle.
  • You want to start without paying.
  • You work on Linux, Windows.
  • You also want cri support.
containerd review

Questions people ask

Is K3s or containerd better?
Neither clearly leads. K3s starts at Free and containerd at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, K3s or containerd?
K3s starts at Free and containerd at Free.
Does K3s or containerd run on more platforms?
K3s runs on Linux, ARM, Self-hosted. containerd runs on Linux, Windows.
Can I use K3s for free?
Both have a free tier, so you can try either at no cost before committing.
What is K3s best used for?
K3s is most often used for kubernetes on edge sites and iot hardware where full clusters will not fit, development and ci clusters that must start fast and cost nothing, small production clusters where full kubernetes is more operations than the workload justifies, teaching and learning kubernetes without cloud spend. Of those, kubernetes on edge sites and iot hardware where full clusters will not fit and development and ci clusters that must start fast and cost nothing are not what containerd is typically brought in for.
What can K3s do that containerd cannot?
K3s covers Single binary, SQLite by default, Certified conformant, Batteries included. containerd covers Full container lifecycle, CRI support, OCI compliant, Snapshotter plugins.

Answered from the vendors’ own pages

K3s: Is K3s free?

Yes. K3s is open source with no licence fee. SUSE sells commercial support around Rancher separately.

containerd: Is containerd free?

Yes. It is an open-source CNCF graduated project with no licence fee.

K3s: Is K3s real Kubernetes?

Yes. It is CNCF-certified conformant, so standard manifests, kubectl and Helm charts work without modification.

containerd: Do I need containerd if I use Docker?

You already have it. Docker uses containerd underneath to run containers; it is not an alternative you install separately.

K3s: Why is K3s smaller than Kubernetes?

It strips legacy, alpha and in-tree cloud provider code, packages everything as one binary, and defaults to SQLite instead of etcd.

containerd: Why did Kubernetes drop Docker for containerd?

Kubernetes talks to runtimes through the Container Runtime Interface. Docker did not speak CRI natively and needed a shim, so Kubernetes removed the shim and talks to containerd directly, which Docker was already using anyway.

K3s: Can K3s run in production?

Yes, and it does, particularly at the edge and for small clusters. For a highly available control plane you need to move off the SQLite default to etcd or an external datastore.

containerd: Can containerd build images?

No. Image building is deliberately out of scope. Tools such as Buildah, BuildKit or Docker handle that.

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