Preface

We have been fiddling with virtualization techniques and tools for quite a long time now in order to establish the much-demanded software portability. The inhibiting dependency factor between software and hardware needs to be decimated by leveraging virtualization, a kind of beneficial abstraction, through an additional layer of indirection. The idea is to run any software on any hardware. This is achieved by creating multiple virtual machines (VMs) out of a single physical server, with each VM having its own operating system (OS). Through this isolation, which is enacted through automated tools and controlled resource sharing, heterogeneous applications are accommodated in a physical machine.

With virtualization, IT infrastructures become open, programmable, remotely monitorable, manageable, and maintainable. Business workloads can be hosted in appropriately-sized virtual machines and delivered to the outside world, ensuring broader and more frequent utilization. On the other hand, for high-performance applications, virtual machines across multiple physical machines can be readily identified and rapidly combined to guarantee any kind of high-performance requirement.

The virtualization paradigm has its own drawbacks. Because of the verbosity and bloatedness (every VM carries its own operating system), VM provisioning typically takes a while, the performance goes down due to excessive usage of computational resources, and so on. Furthermore, the growing need for portability is not fully met by virtualization. Hypervisor software from different vendors comes in the way of ensuring application portability. Differences in the OS and application distributions, versions, editions, and patches hinder smooth portability. Computer virtualization has flourished, whereas the other, closely associated concepts of network and storage virtualization are just taking off. Building distributed applications through VM interactions invites and involves some practical difficulties.

Let's move on to containerization. All of these barriers contribute to the unprecedented success of the idea of containerization. A container generally contains an application, and all of the application's libraries, binaries, and other dependencies are stuffed together to be presented as a comprehensive, yet compact, entity for the outside world. Containers are exceptionally lightweight, highly portable, easily and quickly provisionable, and so on. Docker containers achieve native system performance. The greatly articulated DevOps goal gets fully fulfilled through application containers. As best practice, it is recommended that every container hosts one application or service.

The popular Docker containerization platform has come up with an enabling engine to simplify and accelerate the life cycle management of containers. There are industry-strength and openly automated tools made freely available to facilitate the needs of container networking and orchestration. Therefore , producing and sustaining business-critical distributed applications is becoming easy. Business workloads are methodically containerized to be easily taken to cloud environments, and they are exposed for container crafters and composers to bring forth cloud-based software solutions and services. Precisely speaking, containers are turning out to be the most featured, favored, and fine-tuned runtime environment for IT and business services.

This book is meticulously designed and developed in order to empower developers, cloud architects, business managers, and strategists with all the right and relevant information on the Docker platform and its capacity to power up mission-critical, composite, and distributed applications across industry verticals.