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 services in OpenShift

Similarly to Kubernetes, OpenShift services represent an interface between clients and the actual application running in the pods. A service is an IP:port pair which forwards traffic to backend pods in a round-robin fashion.

By running the oc new-app command, OpenShift creates a service automatically. We can verify this by running the oc get services command:

$ oc get services
NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
ruby-ex 172.30.173.195 <none> 8080/TCP 1h

The output is similar to what we got with the kubectl get services command in Kubernetes. We can delete and recreate this service again by running the oc delete and oc expose commands. Before we do that, run the curl command inside the Minishift VM to verify that the service is up and running:

$ minishift ssh "curl -I -m3 172.30.173.195:8080&quot...