This article deals with Docker and its usage in the cloud. The first part gives a brief and easy to understand introduction to Docker and motivates its usage as a PaaS service. The second part introduces the Oracle Container Cloud Service (OCCS) and explains the key components of OCCS.
Docker has been a tremendous success over the last three years. From an almost unknown and rather technical open source technology in 2014, it has evolved into a standardized runtime environment now officially supported for many Oracle enterprise products.
The core concepts of Docker are images and containers. A Docker image contains everything that is needed to run your software: the code, a runtime (e.g. the JVM), drivers, tools, scripts, libraries, deployments, etc.
A Docker container is a running instance of a Docker image. However, unlike in traditional virtualization with a type 1 or type 2 hypervisor, a Docker container runs on the kernel of the host operating system. Within a Docker image there is no separate operating system, as illustrated in Figure 1.
Isolation vs. Virtualization
Every Docker container has its own file system, its own network stack (and therefore its own IP address), its own process space, and defined resource limitations for CPU and memory. Since a Docker container does not have to boot an operating system, it starts up instantly. Docker is about isolation, i.e. separating the resources of a host operating system, as opposed to virtualization, i.e. providing a guest operating system on top of the host operating system.
Incremental Files System
The file system of a Docker image is layered, with copy-on-write semantics. This enables inheritance and reuse, saves resources on disk, and enables incremental image download. Read the complete article here.
For regular information become a member in the WebLogic Partner Community please visit: http://www.oracle.com/partners/goto/wls-emea ( OPN account required). If you need support with your account please contact the Oracle Partner Business Center.