Top 50 Openshift interview questions and answers

Openshift interview questions and answers

Table of Contents

Q1. What Is Openshift?

Answer : OpenShift is a cloud development Platform as a Service (PaaS) hosted by Red Hat. It’s an open source technology which helps organizations move their traditional application infrastructure and platform from physical, virtual mediums to the cloud. It supports a very large different of applications, which can be easily developed and deployed on OpenShift cloud platform.

Q2. Why Use Open Shift?

Answer : OpenShift provides a common platform for enterprise units to host their applications on cloud without worrying about the underlying operating system. This makes it very easy to use, develop, and deploy applications on cloud. One of the key features is, it provides managed hardware and network resources for all kinds of development and testing. With OpenShift, PaaS developer has the freedom to design their required environment with specifications.

Q3. What Are The Features Of Openshift?

Answer : There are different features supported by Open Shift:

  • Openshift has rich command line toolset.
  • Multiple database and Language Support Provides support for continuous integration and release management.
  • Extensible Cartridge System
  • One-Click Deployment
  • Multi Environment Support
  • Standardized Developers’ workflow
  • Automatic Application Scaling
  • Responsive Web Console
  • Rich Command-line Toolset
  • Provide support for remote SSH login to application.
  • Rest API Support
  • Self-service on Demand Application Stack
  • Remote Debugging of Applications
  • Built-in Database Services
  • Continuous Integration and Release Management
  • IDE Integration

Q4. What Is Openshift Origin?

Answer : OpenShift Origin is the upstream community project used in OpenShift Online, OpenShift Dedicated, and OpenShift Container Platform. Built around a core of Docker container packaging and Kubernetes container cluster management, Origin is augmented by application lifecycle management functionality and DevOps tooling. Origin provides an open source application container platform. All source code for the Origin project is available under the Apache License (Version 2.0) on GitHub.

Q5. What Is Openshift Online?

Answer : OpenShift Online is Red Hat’s public cloud application development and hosting service. It is an offering of OpenShift community using which one can quickly build, deploy, and scale containerized applications on the public cloud. It is Red Hat’s public cloud application development and hosting platform, which enables automated provisioning, management and scaling of application which helps the developer focus on writing application logic.

Q6. Explain Openshift Dedicated?

Answer : OpenShift Dedicated is Red Hat’s managed private cluster offering, built around a core of application containers powered by Docker, with orchestration and management provided by Kubernetes, on a foundation of Red Hat Enterprise Linux. It’s available on the Amazon Web Services (AWS) and Google Cloud Platform (GCP) marketplaces.

Q7. What Is Openshift Enterprise?

Answer : OpenShift Enterprise by Red Hat is a Platform as a Service (PaaS) that provides developers and IT organizations with an auto-scaling, cloud application platform for deploying new applications on secure, scalable resources with minimal configuration and management overhead. OpenShift Enterprise supports a wide selection of programming languages and frameworks, such as Java, Ruby, and PHP. Integrated developer tools, such as Eclipse integration, JBoss Developer Studio, and Jenkins, support the application life cycle.

Q8. What Is Routes In Openshift?

Answer : In OpenShift Routes is a way to externalize the services by providing externally reachable hostname. In OpenShift routes are created using routers developed by admin.

Q9. What Is Source-to-image Strategy?

Answer : In this from source code images are created. In Source-to-image strategy source code is downloaded and compiled and deployed in same container. From same code image is created.

Q10. What Is Openshift Container?

Answer : OpenShift Container Platform (formerly known as OpenShift Enterprise) is Red Hat’s on-premises private platform as a service product, built around a core of application containers powered by Docker, with orchestration and management provided by Kubernetes, on a foundation of Red Hat Enterprise Linux.

Q11. What Is Automation?

Answer : OpenShift automates source code management, application builds, deployments, scaling, health management and more.

Q12. What Is Pod?

Answer : A pod is collection of containers and its storage inside a node of a Kubernetes cluster. It is possible to create a pod with multiple containers inside it. Following is an example of keeping a database container and web interface container in the same pod.

Q13. What Are Stateful Pods?

Answer : StatefulSets are a Kubernetes feature that enables pods to be stopped and restarted while retaining the same network address and storage attached to them. StatefulSets (PetSets in OCP 3.4) are still an experimental feature, but full support should be added in an upcoming release.

Q14. What Are Deployment Strategies?

Answer : A deployment strategy is a way to change or upgrade an application. The aim is to make the change without downtime in a way that the user barely notices the improvements. The most common strategy is to use a blue-green deployment. The new version (the blue version) is brought up for testing and evaluation, while the users still use the stable version (the green version). When ready, the users are switched to the blue version. If a problem arises, you can switch back to the green version.

Q15. What Is Rolling Strategy?

Answer : A rolling deployment slowly replaces instances of the previous version of an application with instances of the new version of the application. A rolling deployment typically waits for new pods to become ready via a readiness check before scaling down the old components. If a significant issue occurs, the rolling deployment can be aborted.

Q16. What Is Canary Deployments?

Answer : All rolling deployments in OpenShift Origin are canary deployments; a new version (the canary) is tested before all of the old instances are replaced. If the readiness check never succeeds, the canary instance is removed and the deployment.

Q17. What Is Deployment Pod Resources?

Answer : A deployment is completed by a pod that consumes resources (memory and CPU) on a node. By default, pods consume unbounded node resources. However, if a project specifies default container limits, then pods consume resources up to those limits. Another way to limit resource use is to (optionally) specify resource limits as part of the deployment strategy.

Q18. What Is Blue/green Deployments?

Answer : The Blue/Green deployment strategy minimizes the time it takes to perform a deployment cutover by ensuring you have two versions of your application stacks available during the deployment. We can make use of the service and routing tiers to easily switch between our two running application stacks—hence it is very simple and fast to perform a rollback.

Q19. Define Authentication In Openshift?

Answer : In OpenShift master has inbuilt OAuth server which generates tokens that can be used for API authentication.

Q20. What Is Haproxy On Openshift?

Answer : On OpenShift, if your application is scalable, HAProxy sits in front of it and accepts all incoming connections. It parses the HTTP protocol and decides which application instance the connection should be routed to. This is important as it allows the user to have sticky sessions.

Q21. What is Haproxy?

Answer : If our application is scalable, then HAProxy will accept all the incoming connections. It analyzes the HTTP protocol and determines to which instance of the application the connection is to be routed. That’s important because it enables the user to get sticky sessions.

Q22. How gear differs from the container?

Answer : Both the words “gear” and “container” are interchangeable. The containers are accurately mapped using one to one relations between the images. However, for gears, numerous cartridges may form part of one gear. For containers, pods carry out the collocation concept.

Q23. What do you mean by Application Scaling?

Answer : In the OpenShift application, auto-scaling is also referred to as pod auto-scaling. Two kinds of application scaling are available:

Vertical Scaling: To meet a higher load with vertical scaling, the application stays in the same place where you provide it with more resources. For instance, you can add a bigger machine with faster CPUs, more CPU, memory or disk space. The cost continues to increase with the addition of hardware resources.

Horizontal Scaling: To allow a higher load with the help of horizontal scaling, several instances of an application are created, and application load is distributed among independent nodes.

With the expansion of the user base, the load and demand for applications increases. To maintain this demand, we need either horizontal scaling or vertical scaling.

Q24. What is Openshift Online?

Answer : OpenShift online is the OpenShift community service that enables the rapid creation, deployment and expansion of containerized applications in the public cloud. This is the platform for development and hosting by Red Hat’s public cloud platform, that allows automated provisioning, application scaling and management to assist developers in focusing on the development of the framework logic.

Q25. What is Downward API?

Answer : The Downward API is a mechanism by which pods can fetch their metadata without the need for the Kubernetes API. Following is the metadata that can be recovered and used for configuring the running pods:

Annotations Labels Information related to Pod CPU/memory request and limit Namespace, Pod name, and IP address Some information can be set up in the pod as an environment variable, while other information is accessible as files in a volume.

Q26. Why Docker and Kubernetes in Openshift?

Answer: Docker assists in the creation of lightweight liner-based containers, whereas Kubernetes assists in the orchestration and management of containers. OpenShift runs over Docker and Kubernetes. All the containers are built over the Docker cluster, that is essentially the Kubernetes service over Linux machines, with the help of the Kubernetes orchestration feature. In this process, we build a Kubernetes master that controls all nodes and will deploy containers across all nodes. Kubernetes’ primary purpose is to control the OpenShift cluster and deployment flow with a different configuration file. Like in Kubernetes, we use kubctl. Similarly, we use the OC command-line utility for developing and deploying containers on the cluster nodes.

Q27. What is Volume Security?

Answer: Volume security signifies securing the PVC and PV of projects within the OpenShift cluster. There are mostly four sections for controlling volume access within OpenShift.

  • runAsUser
  • fsGroup
  • seLinuxOptions
  • Supplemental Groups

Q28. Explain labels in Open-shift.

Answer: In OpenShift, the labels identify metadata that is made up of key/value pairs attached to the resources. Labels can be used to add identifying attributes to the objects which are related to the users and may be used to reflect the organizational or architectural concepts. Labels may be used in combination with label selectors for identifying individual resources or the resource groups uniquely. Examples: Tier, Relationship, Node types, etc.

Q29. What is the source-to-image strategy?

Answer: Source-to-image strategy is used to create source code images. This is achieved by downloading and compiling the same container. The images are created according to the same code. Within the customized strategy, jar and rpm are created.

Q30. Why choose Openshift?

Answer: OpenShift offers a common platform for business units to host their applications in the cloud irrespective of the underlying operating system. This makes the use, development and deployment of applications in the cloud extremely easy. A major feature is that it offers network resources and managed hardware for all sorts of development and testing. With OpenShift, the PaaS developers are free to design the environment they need with specifications.

Q31. Do you know about OpenShift cartridges?

Answer: OpenShift cartridges have also popped up as an important OpenShift interview question. OpenShift cartridges are central points for developing applications. Every cartridge has specific libraries, build mechanisms, source code, routing logic, and connection logic alongside pre-configured environment. All these factors help in running your application.

Q32. What is the difference between gear and container?

Answer: You can find the latest OpenShift interview questions focused on difference-based evaluations. The terms ‘container’ and ‘gear’ are interchangeable. Containers have a precise mapping involving one-to-one relations among images. However, in the case of gears, many cartridges can become part of a single gear. In the case of containers, pods fulfill the collocation concept.

Q33. What is the Source-to-Image (S2I) strategy?

Answer: This strategy involves the creation of source code images through downloading and compilation of the same container. The images are created from the same code, and with a custom strategy, rpm and jar get developed.

Q34. How OpenShift uses Docker and Kubernetes?

Answer: Kubernetes and Docker could work OpenShift in the form of a control system. You can find this question among the latest OpenShift interview questions commonly. The control system helps in enabling many deployment pipelines that are ideal for later use in auto-scaling, testing, and other processes.

Q35. What are the build strategies in OpenShift?

Answer: The common build strategies in OpenShift are Docker strategy, custom strategy, Source to Image strategy, and pipeline strategy.

Q36. Why do we need DevOps tools?

Answer: The applications of DevOps tools are ideal for improving flexibility in software delivery. In addition to this, DevOps tools also help in improving deployment frequency and reducing failure rates. Furthermore, DevOps tools also help in faster recovery and better time management between repairs.

Q37. What is the difference between OpenShift and OpenStack?

Answer: Candidates can find this question among crucial OpenShift interview questions. The primary difference is that OpenStack provides Infrastructure as a Service (IaaS). Furthermore, OpenStack is different from OpenShift by providing object storage and block storage to a bootable virtual machine.

Q38. What are Build configurations?

Answer: Build configuration resources help in configuration and control of builds. Build configuration includes details about a specific build strategy and the source of developer-supplied artifacts like output image.

Q39. Name some identity providers in OAUTH.

Answer: The identity providers in OAUTH are HTTPassword, LDAP, Allow All, Deny All, and Authentication.

Q40. Do you know about OpenShift Online?

Answer: OpenShift online is the public service of Red Hat for cloud application development and hosting.

Q41. Define routes and services in Openshift?

Answer: A pod is comprising services and containers; subsequently, service in Openshift is a get together of coherent pods. The service is considered fundamentally as a REST object in Openshift. Routes are given in Openshift to externalize and investigate the services needed to reach the hostname remotely. It is achieved by utilizing the routes created by the admin commands.

Q42. Enlist a few build strategies that are used in Openshift?

Answer: Following are the major build strategies used in Openshift:

  • Custom Strategy
  • Source to image Strategy
  • Docker Strategy
  • Pipeline Strategy

Q43. Differentiate Openstack and Openshift?

Answer: The two of them are the original inception from open-source projects, and they similarly give Cloud Computing essentials. The significant distinction between them is that OpenStack provides a framework for administration or the structure ‘IaaS.’ It additionally provides object storage and blocks storage to the bootable virtual machine. Then again, Openshift performs unexpectedly.

Q44. List out the most important features of Openshift?

Answer: Following are the prominent features of Openshift:

  • It supports various databases and languages.
  • Agreeable towards the environment sustain.
  • It seriously gives a web console.
  • It gives remote debugging.
  • It has the capability of a rich command-line tool.
  • It helps to remote login to the application through SSH.

Q45. Explain about Openshift Deployment?

Answer: Deployment in OpenShift is a replication regulator dependent on a user-defined layout called a deployment arrangement. Deployments are composed or in response to triggered functions. The deployment framework gives the accompanying:

  • A deployment arrangement is a layout for deployments.
  • Triggers that drive computerized organizations in response to occasions.
  • Client adaptable strategies to progress from the previous arrangement to the new deployments. Rollbacks to preceding deployments.
  • Manual replication scaling.

Q46. Explain the deployment strategies?

Answer: An organization technique is an approach to change an application or to refresh it. The objective is to make progress such that the buyer scarcely sees the changes, without personal time. Utilizing a blue-green sending is the most standard method.
The new form (the blue variant) is being worked for testing and assessment, while the clients utilize the steady-state (the green). The clients are moved to the blue adaptation when it’s accessible. You can return to the Green form if an issue happens.

Q47. Explain the rolling strategy?

Answer: A moving rollout slowly replaces examples of an application’s earlier form with cases of the application’s present rendition. A rolling deployment typically trusts that new units will prepare through a status test until the old modules are downsized. The moving organization can be stopped if a problematic issue happens.

Q48. Explain about the Canary Deployments?

Answer: All rolling organizations in OpenShift Origin are canary arrangements; it checks another adaptation (the canary) before supplanting all the old examples. Except if the availability test never works, at that point, the canary occasion and sending will be handicapped.

Q49. Explain about Openshift Online?

Answer: OpenShift Online is an OpenShift people group administration that permits one to make, convey, and scale containerized applications on the public cloud rapidly. It is the turn of events and facilitates the foundation of Red Hat’s public cloud stage, which empowers automated provisioning, the board, and application scaling to help designers focus on the advancement of system rationale.

Q50. Explain about DevOps?

Answer: DevOps assist associations with reacting a more agile way of changing business prerequisites by:

  • Computerizing and observing the cycle of programming creation,
  • from a mix, testing, delivering to sending, and overseeing it.
  • Smoothing out the turn of events and delivery pipeline
  • Expanding the deployment recurrence.
  • Decreasing the advancement cycles.
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