Book Image

Learn OpenShift

By : Denis Zuev, Artemii Kropachev, Aleksey Usov
Book Image

Learn OpenShift

By: Denis Zuev, Artemii Kropachev, Aleksey Usov

Overview of this book

Docker containers transform application delivery technologies to make them faster and more reproducible, and to reduce the amount of time wasted on configuration. Managing Docker containers in the multi-node or multi-datacenter environment is a big challenge, which is why container management platforms are required. OpenShift is a new generation of container management platforms built on top of both Docker and Kubernetes. It brings additional functionality to the table, something that is lacking in Kubernetes. This new functionality significantly helps software development teams to bring software development processes to a whole new level. In this book, we’ll start by explaining the container architecture, Docker, and CRI-O overviews. Then, we'll look at container orchestration and Kubernetes. We’ll cover OpenShift installation, and its basic and advanced components. Moving on, we’ll deep dive into concepts such as deploying application OpenShift. You’ll learn how to set up an end-to-end delivery pipeline while working with applications in OpenShift as a developer or DevOps. Finally, you’ll discover how to properly design OpenShift in production environments. This book gives you hands-on experience of designing, building, and operating OpenShift Origin 3.9, as well as building new applications or migrating existing applications to OpenShift.
Table of Contents (24 chapters)

Managing pods in OpenShift

OpenShift pods are Kubernetes pods that represent a collection of containers, and each pod serves as a basic management unit. All containers in a pod share the same storage volumes and network. In order to get a list of pods in OpenShift, we can use the oc get pods command:

$ oc get pods
NAME READY STATUS RESTARTS AGE
ruby-ex-1-build 0/1 Completed 0 1h
ruby-ex-1-zzhrc 1/1 Running 0 56m

It is no different from the Kubernetes pod, which means behind the scenes it is a Docker container running. The only difference is that there are two containers now. One of them is a container (ruby-ex-1-build) that is used to build the final image with the source code applied. We can easily verify this by running the docker ps command inside the Minishift VM:

$ minishift ssh docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS...