DOCKER

Docker is an open source platform that enables developers to build, deploy, run, update and manage?containers—standardized, executable components that combine application source code with the operating system (OS) libraries and dependencies required to run that code in any environment.

Containers?simplify development and delivery of distributed applications. They have become increasingly popular as organizations shift to?cloud-native?development and hybrid?multicloud?environments. It’s possible for developers to create containers without Docker, by working directly with capabilities built into Linux and other operating systems. But Docker makes?containerization?faster, easier and safer. At this writing, Docker reported over?13 million developers using the platform?(link resides outside ibm.com).

Docker also refers to?Docker, Inc.?(link resides outside ibm.com), the company that sells the commercial version of Docker, and to the?Docker open source project to which Docker, Inc, and many other organizations and individuals contribute.

Containers?are made possible by process isolation and virtualization capabilities built into the Linux kernel. These capabilities—such as?control groups?(Cgroups) for allocating resources among processes, and?namespaces?for restricting a processes access or visibility into other resources or areas of the system—enable multiple application components to share the resources of a single instance of the host operating system in much the same way that a hypervisor enables multiple?virtual machines (VMs)?to share the CPU, memory and other resources of a single hardware server.?

As a result, container technology offers all the functionality and benefits of VMs—including application isolation, cost-effective scalability, and disposability—plus important additional advantages:

• Lighter weight: Unlike VMs, containers don’t carry the payload of an entire OS instance and hypervisor. They include only the OS processes and dependencies necessary to execute the code. Container sizes are measured in megabytes (vs. gigabytes for some VMs), make better use of hardware capacity, and have faster startup times.?
• Improved developer productivity: Containerized applications can be written once and run anywhere. And compared to VMs, containers are faster and easier to deploy, provision and restart. This makes them ideal for use in?continuous integration?and?continuous delivery?(CI/CD) pipelines and a better fit for development teams adopting Agile and?DevOps?practices.
• Greater resource efficiency: With containers, developers can run several times as many copies of an application on the same hardware as they can using VMs. This can reduce cloud spending.

Companies using containers report other benefits including improved app quality, faster response to market changes and much more. Learn more with this interactive tool

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