We have been talking about virtualization technique and tools for quite a long time now to establish the much-demanded software portability. The inhibiting dependency factor between software and hardware gets decimated with the leverage of virtualization, a kind of beneficial abstraction, through an additional layer of indirection. The idea is to run any software on any hardware. This is by creating multiple virtual machines (VMs) out of a single physical server, and each VM has its own operating system (OS). Through this isolation enacted through automated tools and controlled resource sharing, heterogeneous applications are being accommodated in a physical machine.
There are other noteworthy virtualization induced benefits such as physical infrastructures are being transitioned and exposed as a dynamic collection of software-defined virtual infrastructures. For long, IT infrastructure has been closed, inflexible and sometimes monolithic. And now 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 higher utilization. On the other side, for high-performance applications, virtual machines across multiple physical machines can be readily identified and rapidly combined to guarantee any kind of high-performance needs.
Thus there is no iota of doubt in emphatically stating that virtual machines (VMs) are the most adaptive, network-accessible, application-aware, and fully isolated building-block for next-generation IT. This movement is being supported with the consistent maturity and stability of an array of tools for enabling centralised and cognitive tracking and management of even geographically distributed VMs. With the availability of advanced algorithms and techniques for automated capacity planning, enhanced reliability and higher availability for ensuring the business continuity (BC) and the auto-scaling needs, the era is virtualization has solidly settled for the increasingly connected and IT-enabled world.
However virtualization has its own drawbacks. Because of the verbosity and bloatedness (every VM carries its own operating system), VM provisioning typically takes some minutes, the performance goes down due to the excessive usage of compute resources, etc. Further on, the much-published portability need is not fully met by virtualization. The hypervisor software from different vendors comes in the way of ensuring the application portability. The OS and application distribution, version, edition, patch differences hinder the smooth portability. The compute virtualization flourished whereas the other closely associated network and storage virtualization concepts are just taking off. Building distributed applications through VM interactions invites and involves some practical difficulties.
All these barriers coolly contribute for the unprecedented success of the containerization idea. A container generally contains an application and all 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, etc. Containers achieve the native system performance. The greatly articulated DevOps goal gets fully fulfilled through application containers. As a best practice, every container is recommended to host one application or service.
The popular Docker containerization platform has come out with an enabling engine to simplify and accelerate the lifecycle management of containers. There are industry-strength and open automated tools made freely available for facilitating the needs of container networking and orchestration. Thereby 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, favoured and fine-tuned runtime environment for IT and business services.
On distributed application design and development, the hugely successful service oriented architecture (SOA) has been the most prescribed and preferred architectural pattern. Enterprise-class applications are being constructed as a dynamic collection of easily manageable services. In the recent past, micro service architecture (MSA), a direct offshoot of SOA, is being proclaimed as an architectural construct to suitably and subtly decimate the rising developmental and management complexities of software-intensive solutions. This is achieved through the disentangling of the software functionality into a set of discrete, self-defined and contained, easily manageable services. These services are built around business capabilities and are independently deployable through automated tools. Each micro service can be deployed without interrupting the other micro services. With the monolithic era is all set to fade away sooner than later, the newly incorporated architecture pattern of MSA is slowly yet steadily emerging as a championed and correct way to design, build and sustain large-scale software systems to be hosted and delivered from cloud environments.
MSA not only enables the loose coupling and the software modularity but is a definite boon for continuous integration and deployment that are the hallmarks of the agile world. As we all know, introducing changes in one part of an application mandating for changes across the application has been a bane to the goal of continuous deployment. MSA needs light-weight mechanisms for small and independently deployable services, scalability and portability. Those requirements can be easily met by smartly using containers. Containers provide an ideal environment for service deployment in context of speed, scale, isolation management, and lifecycle. It is easy to deploy new versions of services inside containers. Containers are better suited for micro services than virtual machines because micro services can start up and shut down more quickly. In addition, computing, memory, and other resources can scale independently.
Micro services are the fine-grained units of execution and are designed to do one thing very well at a time. Each microservice has exactly one well-known entry point. Micro services communicate with each other through language and platform-agnostic application programming interfaces (APIs). These APIs are typically exposed as RESTful service endpoints or can be even invoked via lightweight messaging protocols such as RabbitMQ. Micro services are loosely coupled with each other avoiding synchronous and blocking-calls whenever possible. Micro services have a number of benefits. A key benefit is that different services can use different development technologies. Since each service is typically quite small, it is practical to rewrite it using a different technology. That is, micro services make it easier to trial and adopt new and emerging technologies. Instead of launching multiple instances of an application server, the key software infrastructure for web, mobile, enterprise and cloud applications, it is possible to scale-out a specific microservice on-demand. When the load shifts to other parts of the application, the earlier provisioned microservice can be scaled-in while scaling-out a different service. This delivers a better value for IT infrastructures. That is, instead of provisioning a new VM or a bare metal server, a container is freshly created. One major drawback of micro services is the development and deployment complexities of distributed systems are bound to go up. Trustfully there will be standardized tools for effective tracking and managing service containers.
With the faster maturity of several promising and potential technologies such as cloud, mobility, social, the internet of things (IoT), context-awareness, and data analytics, we can safely expect a string of sophisticated and smart services to be conceived and concretized in the days ahead. MSA will be definitely the competent application architecture and Docker containers are set to be the stimulating and sustainable runtime for distributed applications. In short, MSA-compliant and container-deployed workloads for software-defined cloud environments are going to be exceedingly productive and amenable.