This post is written by Mick Tarsel, an IBM employee and Red Hat partner engineer working on OpenShift and Linux networking.
The Single Node Cluster (SNC) project allows a user to easily spin up an OpenShift “cluster” on a single machine. SNC is used to build the bundles that CodeReady Containers (CRC) uses. Although you must have a valid user OpenShift pull secret, the SNC project is a simple way to set up your own OpenShift instance.
Please note the SNC and CRC projects are “as-is” on the Github repository. At this time, it is not a Red Hat supported solution.
A normal OpenShift 4 cluster (OCP4) is composed of many nodes that are typically represented as physical machines or Virtual Machines (VMs). Even a minimally sized cluster in OpenShift requires many hardware resources in order to experiment with, and this is something you would not be able to run on just your laptop!
When an OCP4 cluster is created, several VMs are created with their respective roles. The two types of nodes in a OCP4 cluster I’ll further discuss are the master and worker nodes. As an example, a high availability cluster in OpenShift would require at least three masters and two worker nodes. Read more about required machines for a cluster.
NOTE: Although the vocabulary may not be appropriate at the time of this release, Red Hat and IBM are changing some terminology in their projects.
The master node manages other nodes in the cluster and schedules pods to run on those nodes, such as worker nodes. Since the worker node is managed by the master node, the worker hosts the pods and runs containerized applications. The worker contains the workload for your cluster. Each cluster has at least one worker node. SNC creates a single VM which is labeled as both the master and worker node:
CRC uses this same design for development and testing; however, at this time, there are some limitations such as upgrading OpenShift versions. Using SNC or CRC you can have a master/worker instance in a single VM:
SNC on Power and Z
The SNC project has been updated to enable both ppc64le and s390x. Since the 4.3 release of OpenShift, these architectures have been included in the official Red Hat mirror. This new multi-arch enablement in SNC is extremely beneficial for developers using Power and Z. Although these architectures are used in data centers around the world and are more than robust enough to handle a cluster, it is much easier and faster to create a single VM in order to run simple tests in OCP4.
To get started with OCP4 on your laptop, check out CRC. If you would like to build your own bundle and set up a single node cluster using Bash, try SNC.
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关于作者
Red Hatter since 2018, technology historian and founder of The Museum of Art and Digital Entertainment. Two decades of journalism mixed with technology expertise, storytelling and oodles of computing experience from inception to ewaste recycling. I have taught or had my work used in classes at USF, SFSU, AAU, UC Law Hastings and Harvard Law.
I have worked with the EFF, Stanford, MIT, and Archive.org to brief the US Copyright Office and change US copyright law. We won multiple exemptions to the DMCA, accepted and implemented by the Librarian of Congress. My writings have appeared in Wired, Bloomberg, Make Magazine, SD Times, The Austin American Statesman, The Atlanta Journal Constitution and many other outlets.
I have been written about by the Wall Street Journal, The Washington Post, Wired and The Atlantic. I have been called "The Gertrude Stein of Video Games," an honor I accept, as I live less than a mile from her childhood home in Oakland, CA. I was project lead on the first successful institutional preservation and rebooting of the first massively multiplayer game, Habitat, for the C64, from 1986: https://neohabitat.org . I've consulted and collaborated with the NY MOMA, the Oakland Museum of California, Cisco, Semtech, Twilio, Game Developers Conference, NGNX, the Anti-Defamation League, the Library of Congress and the Oakland Public Library System on projects, contracts, and exhibitions.
