Literally speaking, a Docker packages goods into a big container and loads them onto ship which they unload upon reaching destination. The goods which were packaged, will of course remain exactly the same way as it was loaded. Speaking in terms of cloud, Docker does exactly that. Containerization is a powerful way to package and deploy tools. Docker, as the name suggests, is a deployment tool that packages your code along with all the dependencies into an application container in such a way that it doesn’t require a full fledged Virtual Machine to run.
This means that if you are running Linux OS on your PC and you package all that application into a container, they will run just as fine on cloud or any standard server. Docker made container based virtualization popular and almost every public cloud provider is jumping on the bandwagon, providing their own Container as a Service (CaaS).
Docker has its own advantages when it comes to Portability. Besides that, we no longer require a virtual machine spun up for each and every app. Why? Because if I run a CoreOS host server and have a guest Container based off of Ubuntu, the Container has the parts that make Ubuntu different from CoreOS. While a Virtual Machine is a whole other guest computer running on top of your host computer (sitting on top of a layer of Virtualization), Docker is an isolated portion of the host computer, sharing the host kernel (OS) and even its binaries/libraries if appropriate.
Docker uses shared Kernel which means that they are much more efficient than hypervisors in terms of system resources. Containers are lightweight which means that there are several VMs that can each run its own application with its own operating system. But there can be thousands of containers in the same server that shares the Kernel’s operating system to execute the work. This in turn means you can leave behind the useless 99.9% VM junk, leaving you with a small, neat capsule containing your application.
Docker is Easy to Launch
Docker has started this new project called Libswarm that would potentially make it easier to use containers in public cloud. Currently, in order to run on a remote cloud server, one has to log in to cloud server (install Docker) and push the image (that your devices have access to) to Docker Registry after which you pull that image down to the cloud server. Only after this when the cloud server is ready to go, can you launch the container.
Using Docker with Libswarm, you only configure Libswarm once, and create all of your Docker images locally – Libswarm deals with the creation and orchestration of getting your container started.
Zero Downtime Deployment
In terms of Deployment, it is always a race about who can deploy often and fast, be fully automatic, accomplish zero-downtime, have the ability to rollback, provide constant reliability across environments, be able to scale effortlessly, and create self-healing systems able to recuperate from failures. This means that you can have DevOps Continuous Integration (CI), Continuous Delivery / Deployment (CD) and leverage Docker ecosystem to deliver often and fast, be fully automatic, accomplish zero-downtime, have the ability to rollback software products.
Containers are a lot less mature than Virtual Machines in terms of running highly developed technology in most critical workloads.Virtualization software vendors have created management systems to deal with hundreds or thousands of virtual machines, and those systems are designed to fit into the existing operations of the enterprise data center. Containers are more of a promising future technology where Developers are working on management systems to assign properties to a set of containers upon launch, or to group containers with similar needs for networking or security together, but they’re still a work in progress.
Docker’s original formatting engine is becoming a platform, with lots of tools and workflows attached. And containers are getting support from some of the larger tech vendors. IBM, Red Hat, Microsoft, and Docker all joined Google last July in the Kubernetes project, an open source container management system for managing Linux containers as a single system.
Docker Containers are not yet proven when it comes to scalability. Meaning, large banks and other enterprises want to explore if the tool can handle massive operations which currently docker hasn’t ventured into. Besides that, containers hold a promising future for lowering the cost of computing, reducing labor cost and faster updates.