Chapter 1. Understanding Red Hat build of MicroShift Welcome to the official Red Hat build of MicroShift 4.18 documentation, where you can learn about MicroShift and start exploring its features. 1.1. MicroShift product documentation To browse the MicroShift 4.18 documentation, use one of the following methods: Use the navigation bars and links to browse. Select the task that interests you from the contents of this Welcome page. To get started with MicroShift, use the following links: Red Hat build of MicroShift release notes Installing Red Hat build of MicroShift For related information, use the following links: Red Hat Device Edge overview RHEL for Edge documentation OpenShift Container Platform documentation 1.2. About Red Hat build of MicroShift Working with resource-constrained field environments and hardware presents many challenges not experienced with cloud computing. MicroShift enables you to solve problems for edge devices by: Running the same Kubernetes workloads you run in the cloud, but at the edge. Overcoming the operational challenge of minimal system resources. Addressing the environmental challenges of severe networking constraints such as low or no connectivity. Meeting the physical constraint of hard-to-access locations by installing your system images directly on edge devices. Building on and integrating with edge-optimized operating systems such as Red Hat Enterprise Linux for Edge (RHEL for Edge). MicroShift has the simplicity of single-node deployment with the functions and services you need for computing in resource-constrained locations. You can have many deployments on different hosts, creating the specific system image needed for each of your applications. 1.2.1. Architectural design MicroShift is a single-node container orchestration runtime designed to extend the benefits of using containers for running applications to low-resource edge environments. Because MicroShift is primarily a platform for deploying applications, only the APIs and features essential to operating in edge and small form factor computing environments are included. For example, MicroShift contains only the following Kubernetes cluster capabilities: Networking Ingress Storage MicroShift also provides the following Kubernetes functions: Orchestration Security To optimize your deployments, use MicroShift with a compatible operating system, such as Red Hat Enterprise Linux for Edge (RHEL for Edge). Using MicroShift and Red Hat Enterprise Linux for Edge (RHEL for Edge) together forms Red Hat Device Edge. Virtual machines are handled by the operating system in MicroShift deployments. Figure 1.1. Red Hat build of MicroShift as part of Red Hat Device Edge. The following operational differences from OpenShift Kubernetes Engine can help you understand where MicroShift can be deployed: 1.2.2. Key differences from OpenShift Kubernetes Engine Devices with MicroShift installed are self-managing Compatible with RPM-OStree-based systems Uses only the APIs needed for essential functions, such as security and runtime controls Enables a subset of commands from the OpenShift CLI ( oc ) tool Does not support workload high availability (HA) or horizontal scalability with the addition of worker nodes Figure 1.2. Red Hat build of MicroShift differences from OpenShift Kubernetes Engine. The figure "Red Hat build of MicroShift differences from OpenShift Kubernetes Engine" shows that OpenShift Kubernetes Engine has the same cluster capabilities as Red Hat build of MicroShift, and adds the following information: Install Over-the-air updates Cluster Operators Operator Lifecycle Manager Monitoring Logging Registry Authorization Console Cloud Integration Virtual Machines (VMs) through OpenShift Virtualization In OpenShift Kubernetes Engine and other OpenShift Container Platform deployments, all of the components from the operating system through the cluster capabilities work as one comprehensive unit, with full cluster services for a multi-node Kubernetes workload. With MicroShift, functions such as over-the-air-updates, monitoring, and logging, are performed by the operating system. 1.3. MicroShift OpenShift APIs In addition to standard Kubernetes APIs, MicroShift includes a small subset of the APIs supported by OpenShift Container Platform. API API group Route route.openshift.io/v1 SecurityContextConstraints security.openshift.io/v1 1.4. MicroShift Kubernetes APIs The Kubernetes API is fully accessible within MicroShift and can be managed with the kubectl command-line tool or the OpenShift Container Platform CLI tool ( oc ). The oc binary is compatible with kubectl and offers a set of features that can be used with MicroShift. Using these command-line tools with MicroShift can help you access all of the resources you need to work with your deployments. Additional resources API index OpenShift Kubernetes Engine

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