Originally created by Solomon Hykes while working at the platform-as-a-service (PaaS) company dotCloud in 2013, Docker is an open-source virtual container that automates the deployment of applications within the virtualized environment. What makes it unique, however, is the way in which applications are handled. With Docker, everything needed to run the application (code, runtime, tools, libraries, etc) is placed in the container; thus, guaranteeing that it will run the same in the any environment.
Docker also adds a layer of abstraction and automation to the OS-level. It then uses resource isolation so that independent containers can run with a single operating system. One of the problems associated with virtual machines is that each one must be given an OS instance, which consumes significant resources (and time). Docker aims to eliminate this hurdle by allowing multiple, independent containers to run on a single operating system.
#1) Resource Isolation
The real beauty of Docker containers is its ability to isolate resources according to an organization's specific needs. With Docker, each container is given its own, isolated resources. Thus, organizations can set up multiple containers, each of which has custom resources based on the application that it is intended to run.
This not only promotes efficient use of resources, but it also simplifies the process of app removal. With each app running in its own container, organizations can delete apps by removing the container, without fear of temporary files and configuration data being left behind on the operating system.
#2) Ease of Configuration
Docker excels in its simplified configuration and setup. Like all virtual machines, it allows organizations to run their own preferred platform on top of their existing structure. What makes Docker stand out from other virtual machines, however, is its elimination of overhead. Docker offers the same utility benefits of other virtual machines but without the overhead, simplifying the process of configuration. Organizations can then take this configuration to use in other environments.
#3) Rapid Deployment
A third benefit of using Docker containers is rapid deployment. IT companies and organizations know full well the importance of deploying applications in a short amount of time. App deployment time and performance go hand in hand, meaning you can expect greater performance when deployment times are reduced. Thankfully, this is an area in which Docker shines. Because Docker contains include only the runtime resources needed to run the respective application, their size is reduced; thus, organizations can deploy them more quickly.
According to this article published by TechRepublic, Docker is capable of running apps in just milliseconds, whereas a traditional VM running the same app would take minutes. Each virtual machine must run a full instance of the operating system, but thankfully this isn't a problem with Docker containers, allowing for significantly faster deployment.
This should come as little-to-no surprise given its popularity and widespread usage, but it's still worth mentioning that Docker can be integrated into a wide variety of infrastructure tools and systems.
Some of the many tools that support Docker integration include the following:
Amazon Web Services (AWS)
Google Cloud Platform
And many more
#5) Enhanced Security
There's still some debate over which method of virtualization is more secure, Docker containers or virtual machines The folks at DZone bring up a good argument for Dockers, however: Docker containers feature “..host OS sensitive mount points as as read-only mount points and uses a copy-on-write filesystem to make sure containers can’t read each other’s data. It also limits system calls to your host OS and works well with SELinux and AppArmor.” Technical jargon aside, if one of your Docker containers is hacked or otherwise infiltrated by an unauthorized user, your other Docker containers will remain safe and secure.
More so, DZone adds that Docker images found on Docker Hub are signed to verify authenticity. And with Docker growing in popularity, we'll likely see even more security measures implemented in the months and years to come.
#6) Lightweight Footprint
When compared to virtual machines, Docker containers have a very small and lightweight footprint. Of course, this leads to several other benefits in itself, one of which is greater portability across machines. Organizations can easily transfer a Docker container, complete with its respective application and resources, to another machine. Docker's lightweight footprint also helps to promote faster deployment.
The Bottom Line
So, just how popular is Docker technology and will it overtake virtual machines? There's no denying the fact that more and more organizations are embracing this versatile new container technology. According to DataDog, 6% of the web hosts it monitored ran Docker containers (Aug 2015). That may sound small, but Docker usage went from 0% to 6% in just one year.
DataDog also found that two-thirds of IT organizations that try Docker containers adopt the technology – and they do within just 30 days of usage. There must be some reason why organizations are eager to use Docker containers. Whether it's the resource isolation, rapid deployment, lightweight footprint, or any of the other benefits listed above, Docker is an attractive choice of container technology that's expected to grow even more popular.
Whether or not Docker containers surpass virtual machines, however, is a question that remains up for discussion. Docker containers offer some undeniable advantages over its VM counterparts, but there are still some reasons to use virtual machines. Migration support is still iffy at best, and they can only run select, compatible operating systems. Also, virtual machines may be deemed more secure in multi-tenant deployment.
Do you think Docker containers will surpass virtual machines?
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