k8s vs k3s: The Comprehensive Difference

Published 22.07.2021

Author Hrittik Roy

Categories Engineering

Kubernetes is undoubtedly a champion in the container orchestration world. But currently, we see that K3s or a lightweight Kubernetes distribution which is light, efficient and fast with a drastically small footprint levelling up.

Businesses nowadays scratch their head what to use K3s or K8s in their production. So, let’s discuss some of the many things that make both K3s and K8s unique in their ways. And if you want to use one of them in your business but want to prevent the struggle to choose one, continue with me on this journey.

Let’s start!

What is K3s?

K3s is a lightweight Kubernetes distribution that Rancher Labs, which is fully certified Kubernetes offering by CNCF. In K3s, we see that the memory footprint or binary which contains the components to run a cluster is small. It means that K3s is small in size.

As K3s has a tiny binary, it is very lightweight, which makes the installation process faster. Also, the deployment of applications with this lightweight Kubernetes is faster. K3s has a built foundation on a single binary which is less than 100 MB in size. As it is so tiny in size, we can even run a K3s cluster in Raspberry Pi (small affordable computer hardware).

k8s vs k3s
K3s Working Structure (Source: K3s)

Advantages of K3s

Small Size

The best advantage of K3s is that it is minimal in size (less than 100 MB), which helps it launch a Kubernetes cluster in small hardware with minimal settings.

Fast Deployment

You can install and deploy k3s with one command under 30 seconds 🙃

curl -sfL https://get.k3s.io | sh -
# Check for Ready node,
takes maybe 30 seconds
k3s kubectl get node


K3s, due to their small memory footprint, is very lightweight, which helps the Kubernetes be up and running very quickly. It means that the binary, which contains all the non-containerized components needed to run a cluster, is smaller.

Continuous Integration

K3s, because of their lightweight environment and small size, helps in continuous integration. It helps in the automation of the integration of codes from multiple contributors into a single project.

Perfect for IoT and Edge Computing

Because of support for ARM64 and ARMv7, K3s is very efficient for Kubernetes distribution in production workloads for resource-constrained IoT devices.

Simplified and Secure

A single binary file of less than 100 MB packages K3s, which makes it simple and also, the single binary file is easy to secure with fewer complications.

What is K8s?

Kubernetes or K8s is the most popular orchestration tool for managing containers. It is portable, flexible, and extensible and supports both imperative/ declarative configuration and automation with a large ecosystem as it’s a CNCF graduate project.

Learn more about Kubernetes here:

Kubernetes is designed to accommodate large configurations (up to 5000 nodes) and helps deploy applications in production.

k8s vs k3s
Kubernetes or K8s Cluster with all components (Source: Kubernetes Documentation)

Advantages of K8s


Kubernetes is highly portable because a variety of other infrastructure and environment configuration uses Kubernetes. Most other orchestrators lack this portability because they are tied to particular runtime or infrastructure.


Kubernetes is very flexible because it can virtually work with any container runtime (the program that runs containers). It is a part of the Kubernetes cluster which relies on CRI-O to integrate Kubernetes with CRI (Container Runtime Interface). But, this integration does not work with all the container runtimes available, e.g. runc or Rkt. It uses kubelet to schedule containers.

Multiple Cloud Capability

Kubernetes is vendor-agnostic, which means it can run on any available infrastructure, including public, private, and hybrid clouds.


The ability to scale an application based on the quantity of incoming traffic is a cornerstone of any modern infrastructure. HPA (Horizontal Pod Autoscaler) is an in-built resource in Kubernetes that determines the required number of replicas for a service. Within Kubernetes, elasticity is a highly automated core component.

Open Source

Kubernetes is open-source and falls under the CNCF umbrella, and so has better compatibility with other tools, which helps the whole project have community-driven contributors helping in quick bug fixing and releases.

k8s vs k3s: Difference

K3s are not functionally different from K8s, but they have some differences that make them unique. K3s can deploy applications faster than K8s. Not only that, K3s can spin up clusters more quickly than K8s. K8s is a general-purpose container orchestrator, while K3s is a purpose-built container orchestrator for running Kubernetes on bare-metal servers.

Kubernetes uses kubelet, an agent running on each Kubernetes node to perform a control loop of the containers running on that node. This agent runs inside the container. However, K3s does not use kubelet, but it runs kubelet on the host machine and uses the host’s scheduling mechanism to run containers.

Again, we can see that K3S is lightweight because of its small size, and this helps it run clusters in IoT devices such as Raspberry Pi, which has limited resources. In contrast, we can see that normal Kubernetes or K8s is not operable in IoT or edge computing devices. Also, K3s supports both ARM64 and ARMv7 with binaries.

Kubernetes or K8s can host workloads running across multiple environments, while K3s can only host workloads running in a single cloud. It mainly happens because K3s don’t contain the capacity to maintain a significant workload on multiple clouds as it is small in size.

At the same time, we can see that Kubernetes, due to its heavy size, takes advantage of hosting workloads and spin up clusters in multiple clouds. K3s is a standalone server, unlike K8s, which is a part of the Kubernetes cluster. K8s relies on CRI-O to integrate Kubernetes with CRI (Container Runtime Interface) while K3s uses CRI-O, and therefore is compatible with all of the supported container runtimes. K8s uses kubelet to schedule containers, but K3s uses the host’s scheduling mechanism to schedule containers.

K3s uses kube-proxy to proxy the network connections of the Kubernetes nodes, but K8s uses kube-proxy to proxy the network connections of an individual container. It also uses kube-proxy to set up IP masquerading, while K3s does not use kube-proxy to do that.

Again, K8s uses kubelet to watch the Kubernetes nodes for changes in the configuration, while K3s does not watch Kubernetes nodes for changes in the configuration. Instead, it receives a deployment manifest containing the configuration information from the Kubernetes control plane and makes changes accordingly.

Kubernetes can be very beneficial when it comes to orchestration (arrangement and coordination of automated tasks) of large databases as it can maintain the load of the database. At the same time, k3s can be more than useful for small databases. It happens to come in a single binary file of less than 100 MB, which will help to fire up quick clusters, faster scheduling pods and other tasks.

k3s can have tighter security deployment than k8s because of their small attack surface area. Another advantage of k3s is that it can reduce the dependencies and steps needed to install, run or update a Kubernetes cluster.

Should I choose k3s or k8s?

From the above discussion, it is visible that both K3s and K8s have their pros and cons, which make them unique and different from each other. Both are very useful, but given a business situation, the usage of a particular can impact.

We have seen how K8s can be beneficial for large applications, and keeping that in mind, a big market cap business that deals with a large amount of data and has its workload distribution in several cloud servers can use K8s, which will help them in a lot of ways.

Medium cap businesses can decide to use both K3s and K8s because they will not have an actual size of the application throughout. It will help them use K8s to deal with the large workloads, while for a quick spin-up of a cluster in small production, K3s can be beneficial. Maintaining the balance between K3s and K8s can help the business save a lot of money while keeping the regular work going.

Small-cap businesses which don’t have any work with the large application can automatically prefer K3s because K3s is very quick while deploying applications with small workloads, and also installation, running, and updates are easy.

Independent developers keen on IoT, and edge computing has a significant advantage while choosing K3s as their Kubernetes distributor. They will be working with many low resources containing computational hardware like Raspberry Pi and others. We all know how K3s comes in a small single binary file and runs on IoT devices due to ARM64 and ARMv7 support.

Final Thoughts

You might think k3s is better than “full-fat” k8s but let me remind you for k3s limitations exist. Currently, k3s doesn’t support running more than a master and any other database apart from SQLite on the master node. So, defining needs and goals is quite important when you choose your default container orchestrator.

I hope you are clear about Kubernetes and k3s to a considerable extent after this post. If you want to learn and explore, the official tutorial would be an excellent place to start. Feel free to dive down into similar posts:

Try k8s here at Play with Kubernetes. For k3s, Civo is offering $250 credits for you to play with!

And if you want us to do all these deployments and orchestrations without worrying about the steep learning curve, feel free to reach out to our engineering team.

Happy Orchestrating!

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