A Linux container keeps applications and their runtime components together by combining lightweight application isolation with an image-based deployment method. Containers introduce autonomy for applications by packaging apps with the libraries and other binaries on which they depend. Containers do not contain an independent operating system kernel, which makes them faster and more agile than virtual machines. However, it does mean that all containers on a host must use the same kernel.
At the core of Red Hat cloud technology is Linux container technology with a base layer running Red Hat Enterprise Linux. Each container is preferably running on some kind of an OpenShift environment, which provides the underlying Red Hat Enterprise Linux operating system. OpenShift uses Docker formatted containers and provides high-level management of multiple containers, including clustering, orchestration and provisioning, monitoring, and logging.
Pivotal also relies on Linux containers within its core cloud technology. However, Pivotal has decided not to work with Docker formatted containers, and instead is using technology known as Warden or Garden (depending on the version of Cloud Foundry being used).
In addition, Pivotal use Ubuntu for the base operating system for Cloud Foundry containers, an operating system which they do not support as part of a Cloud Foundry support contract. As such, Pivotal customers must rely on third parties when operating system fixes and upgrades are made available. Ultimately, Pivotal customers take responsibility for rebuilding container images as needed.
IBM uses a mix of core cloud technology in its BlueMix offering. One BlueMix “cloud” offering currently in beta is virtual machines which are not based on Linux container at all. Other BlueMix services such as OpenWhisk can be viewed as a software as a service (SaaS) offering where the technology enabling the runtime is never exposed to the user.
However, services based on either Cloud Foundry buildpacks or IBM containers are run using Linux containers. IBM BlueMix instance runtimes (Cloud Foundry buildpacks) rely on the Warden container format. The IBM container offering relies on Docker formatted containers.
Each represents very different technologies, but both are run on Ubuntu. However, IBM does not provide direct support of Ubuntu. Customers must rely on third parties for any operating system fixes and upgrades. As a result, IBM customers also take responsibility for rebuilding container images as needed.
Oracle has taken a different approach than Red Hat for cloud technology. Oracle has embraced using of a mix of proprietary hardware and software for its public and private cloud offerings.
For private cloud, Oracle Exalogic Elastic Cloud is positioned as “hardware and software engineered together”. However, only two pieces of Oracle software to enable a private cloud are available for purchase–Oracle Traffic Director and Oracle WebLogic Server Multitenant.
Oracle Traffic Director facilitates interactions between applications. It provides communications, load balancing, rule-based request routing, throttling, SSL, and other features to link applications together.
For Java EE applications, Oracle WebLogic Server Multitenant allows users to pack more applications into each WebLogic server instance. Oracle claims this allows users to do more using fewer resources, and as such consolidate the number of servers needed compared to when multitenancy is not used.
However, researching more details about these Oracle products reveals significant differences from Red Hat core cloud technology. For example, missing from Oracle Traffic Director is support for Red Hat Enterprise Linux. Missing from Oracle Traffic Director and Oracle WebLogic Server Multitenant is support for Docker formatted containers and orchestration using Kubernetes.
Oracle has taken a different path for core cloud technology than Red Hat. Missing from Oracle core cloud technology is the concept of cloud management of resources and the applications that run on them. Instead, Oracle offers administration of Oracle Traffic Director to route and manage traffic to Java applications running on WebLogic Servers. To achieve maximum server density, added administrative complexity is required to configure and use WebLogic Server Multitenan.
Compare this to the Red Hat core technology of Red Hat Enterprise Linux, OpenShift, Docker formatted containers, and Kubernetes. Aside from all being popular open source technologies, they can also be used for a variety of cloud deployments beyond Java applications, such as in-memory data grids, business process management, business rules, data virtualization, and more. Red Hat offers technologies that gain management efficiencies of scale across multiple products. Oracle is offering proprietary technology that is built for specific purposes and sometimes specific technology.