In this post, I have shared some quick tips, including Q/A and useful links from the Day 1 & Day 2 live session of our current batch of OpenShift Certified Specialist Training.
OpenShift is a unique platform for building and shipping cloud-based applications. It opens opportunities for innovative products and services with faster delivery. An organization using Red Hat OpenShift can unleash many advantages and gain competitive benefits in business.
This series will help you better understand and make it easier for you to learn Openshift, clear Certifications & get a better-paid job.
In our OpenShift Certified Specialist Training program, on Day 1 & Day 2 of our training program, we covered these topics:
Then we went ahead with Openshift Architecture concepts and introduced why this is an important aspect in Openshift.
Then we started with the Types of Cluster & Cluster creation in Openshift.
- Types of OpenShift Cluster
- OpenShift Cluster Creation
↦ Before we begin, know everything about the OpenShift Certification
➪ Kubernetes Vs Openshift
A straightforward comparison of the OpenShift and Kubernetes is not befitting simply for the fact that Kubernetes is an open-source project and OpenShift is an offering by Red Hat. However, underneath the covers, OpenShift is powered by Origin Kubernetes Distribution (OKD) and few open-source projects like Kubernetes, Docker, Istio, etc.
Kubernetes is an integral part of the OpenShift. They both feature robust and scalable architecture that enables rapid and large-scale application development, deployment, and management. They both run on the Apache License 2.0. But that’s just about where the likeliness ends but not the analogy. I have tried to cover just a few out of many ways in which OpenShift and Kubernetes differ.
↦ To know more Check Our blog post on OpenShift vs Kubernetes.
Q1. Which is more popular Kubernetes or OpenShift?
Ans: OpenShift is the Enterprise version of K8s, to choose one it all depends on the requirements. Both are popular, and the adaptation of both is only increasing at a brisk pace.
Q2. What is the difference between Openshift Project and Kubernetes Namespace?
Ans: This is a petty difference, but on OpenShift there are projects which are nothing more than just Kubernetes namespaces with added features. A project is essentially the same as a namespace, but OpenShift provides additional administrative controls for projects. If you’re deploying software on OpenShift you’ll basically use the project exactly the same way as a Kubernetes namespace, except a normal user can be prevented from creating their own projects, requiring a cluster administrator to do that.
A good example would be network policies that close your project for external traffic so that is isolated and secure by default – if you want to permit some kind of traffic you would do so by creating additional policies explicitly. In a similar way, you could provide default quotas or objects and make your new projects pre-configured according to your organization’s rules.
➪ Openshift Architecture
OpenShift has layered architecture where Docker and Kubernetes tightly hold layers with each other. Now the obvious question that arises here is, what roles do Docker and Kubernetes play then? So, Docker is responsible for creating Linux-based containers, and Kubernetes performs orchestration of containers on multiple hosts.
In the same process, we build a Kubernetes master in a cluster which controls all the nodes and deploys the containers to all the nodes. So, now let’s see the major component of OpenShift Architecture.
- API Server– With the help of API servers, different tools and libraries communicate with each other.
- Controller Manager – Regulates and manages cluster state, also responsible for gathering and sending information to API servers.
- Etcd– Stores configuration information and has key-value to distribute among nodes for accessibility.
- Scheduler – Helps in distributing workloads to nodes.
- Kubernetes master makes communication with the node server with the following key components:
- Docker- a service that helps in running containers for the application.
- Kubelet Service- Responsible for transferring information to and from the control pane. It receives commands and works from master components. Helps in managing network issues as well as port forwarding.
- Proxy Service- They run on each node and make service available to external hosts. It manages load balancing, health checkups of containers and pods.
- Integrated OpenShift Container Registry- An inbuilt storage for storing Docker images.
Q3. How does Openshift architecture manage containers?
Ans: The Openshift architecture supports and manages Docker containers which are hosted on top of all layers using Kubernetes. OpenShift V3 supports containerized infrastructure.
Q4. What are Infra nodes?
Ans: Infrastructure nodes are nodes that are labeled to run pieces of the OpenShift Container Platform environment. These nodes are also known as Infrastructure nodes.
↦ Learn more about Infra Nodes
Q5. In the architecture, where does the storage fall in?
Ans: Kubernetes stores the file in a database called the etcd. Besides storing the cluster state, etcd is also used to store the configuration details such as the subnets and the configmaps.
OpenShift Container Platform uses the Kubernetes persistent volume (PV) framework to allow cluster administrators to provision persistent storage for a cluster. Developers can use persistent volume claims (PVCs) to request PV resources without having specific knowledge of the underlying storage infrastructure.
↦ Learn more about Persistent Storage
➪ Types of Openshift Cluster
There are three ways of installing OpenShift cluster:
a) Community Edition aka Origin Kubernetes Distribution (OKD):
An OKD stands for Origin Key Distribution, which is the open-source upstream community edition of Red Hat’s OpenShift container platform. OKD is a container management and orchestration platform based on Docker and Kubernetes.
b) Red Hat OpenShift Service on AWS (ROSA):
Red Hat OpenShift Service on AWS (ROSA) is a fully-managed OpenShift service, jointly managed and supported by both Red Hat and Amazon Web Services (AWS). Having your clusters maintained by this service gives you the freedom to focus on deploying applications.
c) Enterprise Edition aka Openshift Container Platform (OCP):
Enterprise Edition aka Openshift Container Platform (OCP) is a consistent hybrid cloud foundation for building and scaling containerized applications. Benefit from streamlined platform installation and upgrades from one of the enterprise Kubernetes leaders.
OCP is an on-premises platform as a service built around Docker containers orchestrated and managed by Kubernetes on a foundation of Red Hat Enterprise Linux.
Q6. What is OKD?
Ans: OKD is a distribution of Kubernetes optimized for continuous application development and multi-tenant deployment. OKD adds developer and operations-centric tools on top of Kubernetes to enable rapid application development, easy deployment and scaling, and long-term lifecycle maintenance for small and large teams. OKD is a sibling Kubernetes distribution to Red Hat OpenShift.
↦ Check out how to create your own OKD Cluster
➪ OpenShift Cluster Creation
In our Day 2 live session, we have installed and configured Multi-Node Openshift (OCP) Cluster using Run It Yourself User Provisioned Infrastructure.
User Provisioned Infrastructure (UPI):
With the release of Red Hat OpenShift 4, the concept of User Provisioned Infrastructure (UPI) has emerged to encompass the environments where the infrastructure (compute, network and storage resources) that hosts the OpenShift Container Platform is deployed by the user. In this type of installation, you as a user deploy underlying infrastructures like Operating System whereas the installer will install Openshift Cluster and openshift related resources.
This allows for more creative deployments while leaving the management of the infrastructure to the user. This allows us to deploy OpenShift Container Platform 4.1 on a mix of virtual and bare-metal machines.
↦ Check out how to create your own OCP Cluster
Q7. What is OpenShift CLI?
Ans: OpenShift CLI is a tool for the management of OpenShift applications from the command line. The OpenShift CLI provides abilities for the management of the end-to-end application lifecycle. It has the features for basic and advanced configuration for applications. Also, it includes functionalities for management, deployment, and adding applications.
Q8. What is OpenShift Virtualization?
Ans: OpenShift Virtualization is a feature of OCP that you can use to run and manage virtual machine workloads alongside container workloads. OpenShift Virtualization adds new objects into your OCP cluster via Kubernetes custom resources to enable virtualization tasks.
Quiz Time!
With our OpenShift Certified Specialist training program, we cover real exam questions to help you prepare for the OpenShift certification.
Check out one of the simple questions and see if you can crack this…
Q. Which three of the following components are common across container architecture implementations? (Choose three.)
A. Container runtime
B. Container permissions
C. Container images
D. Container registries
The right answer will be revealed in my next blog. So, stay tuned!
Feedback
We always work on improving and being the best version of ourselves from the previous session hence constantly ask feedback from our attendees.
Here’s the feedback that we received from our trainees who had attended the session… {2109 here represents a batch of September 2021}
Related/References
- Openshift vs Kubernetes: What is the Difference?
- Kubernetes for Beginners
- Red Hat OpenShift- What, Why, and How?
- OpenShift For Beginners: 30+ Hands-On labs You Must Perform | Step-by-Step
- Deploy Applications Using OpenShift: Step-by-Step
- Install Single Node OpenShift Cluster (OKD): Step By Step
- Install & Configure Multi-Node Openshift (OCP) Cluster Using User Provisioned Infrastructure: Step By Step
- [Q & A] Day 0: OpenShift [Docker Containers, K8s Architecture, & OpenShift Overview]
- OpenShift Official Documentation
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