[Cloud] OpenShift vs OpenStack

1. OpenShift vs OpenStack

OpenStack turns servers into cloud. It can be used to automate resource allocation so customers can provision virtual resources.
OpenShift is a container centric model that leverages core concepts of Kubernetes and packages them in a neat way for developers to deploy applications on the cloud.

1.1. Concerning Containers

OpenStack typically uses hypervisors like KVM, Xen or VMware to spin up virtual machines.
On the other hand, OpenShift can run bare metal or it may run on Virtual Machines but it always uses containers on top of them. The containerization technology that they use is almost exclusively Docker.

(Note: OpenStack does offer containerization support as well, it is meant to be used more of less like VPS and is optional.)

1.2. Distributed System

OpenStack is not exclusively a distributed system. It can take control over an entire data center but that’s nowhere as global as a Kubernetes cluster. You would need a lot of extra layers of software to turn several remote installations of OpenStack into a single distributed system. It may offer distributed storage technologies like Glusterfs and Ceph which you can use to build up your distributed storage stack, but it doesn’t rely on them specifically.

OpenShift is inherently a distributed system (which makes sense since it incorporates Kubernetes into it) and since it is a distributed system it necessarily has one or more master nodes controlling a few worker nodes. Red Hat provides a decent layer for networking to facilitate communication between these nodes and there’s good support for using distributed storage like Glusterfs and Ceph.

1.3. IaaS and PaaS

OpenStack is Infrastructure as a Service (IaaS). It manages servers and offers services that you generally attribute to the cloud VPS providers like DigitalOcean, AWS, Microsoft Azure and Google compute engine. If you are planning to set up your own private data center (due to economics/security reasons), instead of developing your own management utility to run these servers you can deploy OpenStack on them and turn it into your organization’s private cloud.

OpenShift offers Platform as a Service. If you are familiar with Google App Engine where developers are concerned with just the development and testing of their app. The entire server configuration doesn’t matter. Google makes it possible because they containerize the apps running in the cloud. 

This is basically what OpenShift does. OpenShift can containerize the applications your organization is developing. Your DevOps team can set up an entire CD/CI pipeline, do fancy A/B testing, issue tracking and streamline the flow between various stages of development, testing and deployment using OpenShift.

1.4. OpenShift, OpenStack and Hybrid Cloud

It is not necessary to run OpenShift on top of OpenStack, but they can go hand in hand if you desire to. OpenStack does basically the same thing as your cloud service providers (AWS, Azure.etc). You can then install OpenShift on them.

Resource

Openstack:

 https://phoenixnap.com/blog/kubernetes-vs-openstack

 Openshift

 https://medium.com/levvel-consulting/the-differences-between-kubernetes-and-openshift-ae778059a90e

 https://docs.openshift.com/container-platform/3.5/architecture/index.html

 https://www.whizlabs.com/blog/openshift-vs-kubernetes/

 https://medium.com/levvel-consulting/the-differences-between-kubernetes-and-openshift-ae778059a90e

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