What is K3OS and how does it relate to K3s?

What is K3OS and why should you care?

K3OS is a lightweight Linux distribution developed by SUSE Rancher specifically for Kubernetes workloads, with an emphasis on the edge and other low-resource environments. K3OS enables IT teams to build production-grade Kubernetes clusters based on K3s, a Kubernetes distribution that can run on systems with as little as 512 MB of RAM thanks to its minimal resource requirements.

K3OS comprises a single binary that includes everything needed to run Kubernetes so that users can easily deploy Kubernetes clusters. It enhances security by providing the option to serve cluster deployments over HTTPS without installing client certificates on individual nodes. K3OS also features a chroot operation that enables users to run pods in read-only mode.

The benefits of K3OS

K3OS provides organizations and IT teams many benefits, including the following:

• Fast installation. K3OS installs quickly -- Rancher claims it starts up in less than 10 seconds with K3s available.
• Seamless management. IT admins can manage K3OS within Kubernetes without logging in to remote nodes.
• Better security. K3OS contains only the components required to run Kubernetes in Linux distros, minimizing the attack surface.
• Simple configuration. IT admins can configure K3OS with a single configuration file.
• Multi-architecture support. K3OS offers support for multiple architectures, including x86-64 and Arm.

What is K3s?

K3s is a lightweight Kubernetes implementation certified by the Cloud Native Computing Foundation. At less than 40 MB in size, K3s is ideal for resource-constrained environments, such as IoT and edge computing architectures. It's a distribution of the original Kubernetes project developed by Google.

With K3s, users can deploy clusters from scratch on bare-metal servers without installing any additional tools or packages. This creates an intuitive interface to deploy, manage and scale applications across multiple nodes simultaneously using standard Docker commands like docker stack deploy.

At installation, IT admins can configure K3s via environment variables or command-line arguments. Nodes can either operate as part of the control plane or join an existing cluster as a worker node with the same binary. Because K3s separates runtime from workloads, admins can stop and start K3s without affecting running applications. Admins can also easily upgrade or reconfigure K3s by changing the flags in the startup file and restarting K3s.

Advantages and downsides of K3s

One of K3s' top benefits is ease of installation and configuration. It's also less resource intensive and more lightweight than full-fledged Kubernetes.

But K3s also has some drawbacks: Its streamlined design offers fewer features, and it could face stability issues over time as a relatively new project.

The need for a hybrid Linux and Kubernetes distribution

K3OS is a Linux distribution designed specifically to manage Kubernetes clusters. It combines a Linux distribution with a Kubernetes distribution -- when you start a K3OS node, Kubernetes is already running. As Kubernetes clusters consist of several nodes, K3OS therefore provides an easy way to set up Kubernetes clusters on any host.

Patching and upgrading Linux and Kubernetes is always necessary, but performing these processes separately can create challenges:

• Kubernetes patches are often applied without patching the underlying Linux OS, which can pose serious security threats to Kubernetes clusters.
• Despite Kubernetes' ability to handle individual reboots, uncoordinated OS upgrades can cause multiple nodes to go down simultaneously. As a result, the Kubernetes master might lose quorum and disrupt the application workload.

How does K3OS compare with K3s?

K3OS and K3s both enable users to easily deploy Kubernetes clusters. They're designed to eliminate the heavy lifting of installing and configuring an OS when deploying Kubernetes clusters.

K3OS extends K3s' functionality by adding the ability to run entirely from read-only media and does not require state to be stored on disk. It also enables single-binary deployment for OS and Kubernetes components.

With K3OS, IT admins can quickly deploy single-node Kubernetes clusters. K3OS can be used with any virtualization software -- such as VMware vSphere, OpenStack and Hyper-V -- to eliminate conflicts between an organization's chosen hypervisor and container platform.

How does K3s compare with standard Kubernetes?

K3s and Kubernetes have several things in common. They're both open source orchestration platforms that can manage large container deployments.

However, K3s is more lightweight and simpler to use than standard Kubernetes. This makes it a good choice for small deployments or for developers who are new to container orchestration.

Kubernetes, in contrast, is more complex and designed for large deployments. While it offers more features and flexibility than K3s, it can also be more difficult to use.