Most frequently asked OpenShift Interview Questions
What is OpenShift?OpenShift is RedHat's cloud development Platform as a Service (PaaS). OpenShift is a family of containerization software developed by Red Hat. Its flagship product is the OpenShift Container Platform on-premises platform as a service built around Docker containers orchestrated and managed by Kubernetes on a foundation of Red Hat Enterprise Linux.
The free and open source cloud-based platform allows developers to create, test and run their applications and deploy them to the cloud.
OpenShift provides support for Node.js, Ruby, Python, PHP, Perl, and Java and is extensible so that users can add support for other languages. Resources allocated for applications can be automatically or manually scaled so that as demand increases there is no degradation of performance. OpenShift provides portability through the DeltaCloud API so customers can migrate deployments to other cloud computing vendor environments.
Compare Docker and OpenShift?Both Docker and OpenShift implement a PaaS service.
The primary difference is that Docker as a project is focused on the runtime container only, whereas OpenShift (as a system) includes both the runtime container as well as the REST API, coordination, and web interfaces to deploy and manage individual containers.
OpenShift is more of an abstraction layer on container orchestration . OpenShift internally uses Kubernetes for container orchestration. Docker has docker swarm for container orchestration
Can we have two accounts on OpenShift platform?
Use rhc setup -l logindetailsHere logindetails is your registered OpenShift's email address.
Can I use the existing bitbucket git repo with OpenShift?We can use the existing bitbucket git repo with OpenShift using asset pipeline as follows -
hc create-app $APPNAME ruby-1.9 --from-code $BICTBUCKET_GIT_LOCATION
What Is OpenShift Online?OpenShift Online is Red Hat's public cloud application deployment and hosting platform. Get on-demand access to OpenShift to build, deploy and manage scalable containerized applications, operated and supported by Red Hat.
What are pods in OpenShift?OpenShift Online leverages the Kubernetes concept of a pod, which is one or more containers deployed together on one host, and the smallest compute unit that can be defined, deployed, and managed. Pods are the rough equivalent of a machine instance (physical or virtual) to a container.
What is rolling strategy in OpenShift?Rolling Strategy. 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.
What are gears in OpenShift?Gears were a core component of OpenShift v2. Technologies such as kernel namespaces, cGroups, and SELinux helped deliver a highly-scalable, secure, containerized application platform to OpenShift users. Gears themselves were a form of container technology.
OpenShift v3 takes the gears idea to the next level. It uses Docker as the next evolution of the v2 container technology. This container architecture is at the core of OpenShift v3.
What is OpenShift deployment?A deployment in OpenShift is a replication controller based on a user defined template called a deployment configuration. Deployments are created manually or in response to triggered events. The deployment system provides:
- A deployment configuration, which is a template for deployments.
- Triggers that drive automated deployments in response to events.
- User-customizable strategies to transition from the previous deployment to the new deployment.
- Rollbacks to a previous deployment.
- Manual replication scaling.