Kubernetes variations

In the Kubernetes ecosystem, Kubernetes is the flagship among all variations. However, there are some other ships that play very important roles. Next, we will introduce some Kubernetes-like platforms, which serve different purposes in the ecosystem.

Minikube

Minikube is the single-node cluster version of Kubernetes that can be run on Linux, macOS, and Windows platforms. Minikube supports standard Kubernetes features, such as LoadBalancer, services, PersistentVolume, Ingress, container runtimes, and developer-friendly features such as add-ons and GPU support.

Minikube is a great starting place to get hands-on experience with Kubernetes. It's also a good place to run tests locally, especially cluster dependency or working on proof of concepts.

K3s

K3s is a lightweight Kubernetes platform. Its total size is less than 40 MB. It is great for Edge, Internet of Things (IoT), and ARM, previously Advanced RISC Machine, originally Acorn RISC Machine, a family of reduced instruction set computing (RISC) architectures for computer processors, configured for various environments. It is supposed to be fully compliant with Kubernetes. One significant difference from Kubernetes is that it uses sqlite as a default storage mechanism, while Kubernetes uses etcd as its default storage server.

OpenShift

OpenShift version 3 adopted Docker as its container technology and Kubernetes as its container orchestration technology. In version 4, OpenShift switched to CRI-O as the default container runtime. It appears as though OpenShift should be the same as Kubernetes; however, there are quite a few differences.

OpenShift versus Kubernetes

The connections between Linux and Red Hat Linux might first appear to be the same as the connections between OpenShift and Kubernetes. Now, let's look at some of their major differences.

Naming

Objects named in Kubernetes might have different names in OpenShift, although sometimes their functionality is alike. For example, a namespace in Kubernetes is called a project in OpenShift, and project creation comes with default objects. Ingress in Kubernetes is called routes in OpenShift. Routes were actually introduced earlier than Ingress objects. Underneath, routes in OpenShift are implemented by HAProxy, while there are many ingress controller options in Kubernetes. Deployment in Kubernetes is called deploymentConfig. However, the implementation underneath is quite different.

Security

Kubernetes is open and less secure by default. OpenShift is relatively closed and offers a handful of good security mechanisms to secure a cluster. For example, when creating an OpenShift cluster, DevOps can enable the internal image registry, which is not exposed to the external one. At the same time, the internal image registry serves as the trusted registry where the image will be pulled and deployed. There is another thing that OpenShift projects do better than kubernetes namespaces—when creating a project in OpenShift, you can modify the project template and add extra objects, such as NetworkPolicy and default quotas, to the project that are compliant with your company's policy. It also helps hardening, by default.

Cost

OpenShift is a product offered by Red Hat, although there is a community version project called OpenShift Origin. When people talk about OpenShift, they usually mean the paid option of the OpenShift product with support from Red Hat. Kubernetes is a completely free open source project.