Docker Online Training Course

Docker Turning as Biggest Advancement

• Docker provide a way to get a grip on software. You can use Docker to wrap up an application in such a way that its deployment and runtime issues—how to expose it on a network, how to manage its use of storage and memory and I/O, how to control access permissions—are handled outside of the application itself, and in a way that is consistent across all “containerized” apps. You can run your Docker container on any OS-compatible host (Linux or Windows) that has the Docker runtime installed.
• Docker offers many other benefits besides this handy encapsulation, isolation, portability, and control.
• Docker containers are small (megabytes). They start instantly. They have their own built-in mechanisms for versioning and component reuse. They can be easily shared via the public private repository.
• Docker containers make it easier to both build and deploy software—the issues containers address, how they address them, when they are the right answer to the problem, and when they aren’t.

Before Docker containers

• For many years now, enterprise software has typically been deployed either on “bare metal” (i.e. installed on an operating system that has complete control over the underlying hardware) or in a virtual machine (i.e. installed on an operating system that shares the underlying hardware with other “guest” operating systems).
• Naturally, installing on bare metal made the software painfully difficult to move around and difficult to update—two constraints that made it hard for IT to respond nimbly to changes in business needs.
• Then virtualization came along. Virtualization platforms (also known as “hypervisors”) allowed multiple virtual machines to share a single physical system, each virtual machine emulating the behavior of an entire system, complete with its own operating system, storage, and I/O, in an isolated fashion.
• IT could now respond more effectively to changes in business requirements, because VMs could be cloned, copied, migrated, and spun up or down to meet demand or conserve resources.
• Virtual machines also helped cut costs, because more VMs could be consolidated onto fewer physical machines. Legacy systems running older applications could be turned into VMs and physically decommissioned to save even more money.

Docker enables more efficient use of system resources

• Instances of containerized apps use far less memory than virtual machines, they start up and stop more quickly, and they can be packed far more densely on their host hardware. All of this amounts to less spending on IT.
• The cost savings will vary depending on what apps are in play and how resource-intensive they may be, but containers invariably work out as more efficient than VMs. It’s also possible to save on costs of software licenses, because you need many fewer operating system instances to run the same workloads.

Docker enables faster software delivery cycles

• Enterprise software must respond quickly to changing conditions. That means both easy scaling to meet demand and easy updating to add new features as the business requires. 
• Docker containers make it easy to put new versions of software, with new business features, into production quickly—and to quickly roll back to a previous version if you need to. 
• They also make it easier to implement strategies like blue/green deployments.

Docker enables application portability

• Where you run an enterprise application matters—behind the firewall, for the sake of keeping things close by and secure; or out in a public cloud, for easy public access and high elasticity of resources.
• Because Docker containers encapsulate everything an application needs to run (and only those things), they allow applications to be shuttled easily between environments. Any host with the Docker runtime installed—be it a developer’s laptop or a public cloud instance—can run a Docker container.

Docker shines for microservices architecture

• Lightweight, portable, and self-contained, Docker containers make it easier to build software along forward-thinking lines, so that you’re not trying to solve tomorrow’s problems with yesterday’s development methods.
• One of the software patterns containers make easier is microservices, where applications are constituted from many loosely coupled components. By decomposing traditional, “monolithic” applications into separate services, microservices allow the different parts of a line-of-business app to be scaled, modified, and serviced separately—by separate teams and on separate timelines, if that suits the needs of the business. 
• Containers aren’t required to implement microservices, but they are perfectly suited to the microservices approach and to agile development processes generally.