Introduction to Docker Platform: Container Basics and Networking

Hello folks, Welcome back to Learnizo Global. Over a period of time containers, Docker, Kubernetes have drawn the attention of the software industry and have quickly changed the unique pattern of software development and operation methods to a great extent. Docker platform is one of the fastest-growing open-source projects ever, and the ecosystem that has grown around it is evolving at a similar pace. In this article, you will understand basic concepts of Docker Platform, Container basics, and introduction to Kubernetes.

What is a Docker?

Docker is neither a programming language nor a framework for building software. Docker is a tool that helps solve common problems like installing, removing, upgrading, distributing, trusting, and managing software with its open-source Linux software.  Launched in March 2013, Docker works with your operating system to package, ship, and run the software. You can think of Docker as a software logistics provider.

Docker is a command-line program, a background daemon, and a set of remote services that take a logistical approach to solving common software problems and simplifying our experience installing, running, publishing, and removing software. It accomplishes this using a UNIX technology called containers.

Containers and Application containerization

Software organizations in the current industry scenario are focusing mainly on open sources virtualization, interoperability as per the industry demand due to recent technological advancements like Artificial Intelligence, IIoT (Industrial Internet of Things), CV2X (Cellular Vehicle to anything), Open RAN, Private RAN, etc. While dealing with application development, shipping, and networking “Isolation” and controlling the ”isolation” is the core concept to many computing patterns, resource management strategies, and general accounting practices.  This “isolation” is a modified runtime environment that manages the common software problems and manages the complex scenarios of system portability and resource utilization.

Linux containers provide isolation for running programs and Docker is used to control that isolation.

Application containerization, or sandboxing, is an old idea. Almost 40 years back, UNIX-style operating systems via the chroot command. Chroot provided process isolation by changing the root context and execution environment of an application to a particular directory tree while prohibiting access to the remaining file system. Chrooted applications running on the same system share an OS; however, they can’t interact with each other or the OS itself outside of the user-mode system or networking calls. Over the years, other forms of isolation were created, including FreeBSD Jails, Solaris Zones, and groups. Today’s container technology is a direct evolution of these early UNIX capabilities. While vastly more capable, today’s technology is conceptually similar by containers sharing an OS, but having wholly isolated processes, (virtual) networks, and storage environments. Since 2005, after the release of Sun’s Solaris 10 and Solaris Containers, “container” has become the preferred term for such a runtime environment.

Containerization has become an invaluable component of enterprise infrastructure. Major providers of enterprise infrastructure software, such as Microsoft, VMware, Red Hat, and Nutanix, have incorporated containers into their core products. Major cloud services, such as AWS, Azure, Google Cloud, and IBM, offer (and are continually enhancing) container services. The Docker containerization system utilizes a form of OS virtualization that only uses the necessary parts of the host system’s OS. This virtualization assembles components of a distributed application platform that can run on Linux, Windows, and macOS.

Container Networking

Container networking is a method of virtualization that separates applications into independent boxes. Containers are similar to virtual machines (VM’s). Containers can run large, distributed applications with low overhead. They do this by sharing a stripped-down operating system kernel (usually based on Linux), making them more efficient than virtual machines. Containers are also simpler than VMs. They often contain minimal Linux operating systems such as Fedora CoreOS, which is part of the Red Hat family and the successor to CoreOS Container Linux.

Network administrators can use container software systems, such as Docker, to create large platforms for distributed applications that can run in the cloud.

Google is most responsible for bringing containerization into the cloud era through its development of generic process containers on Linux, allowing applications to share system resources while maintaining process isolation and resource control. The technology evolved and was popularized by the Docker container runtime engine and packaging format that became the basis for the Open Container Initiative (OCI).

Container systems take up less space on storage drivers and are faster. With Microservices (Microservices is an architecture method of building applications. The application is broken into small pieces of code that perform a single function. APIs (Application Programming Interfaces) connect the microservices, so they can communicate to one other and act cohesively), each container behaves as though it were its own internet site, complete with its own web server. Containers can address each other’s workloads through API calls. The APIs are parsed by a DNS server designated by the container daemon. Container orchestration systems such as Kubernetes and Apache Mesos are effectively networked operations centers applied to the task of managing container subnets.

Containerized SDN for Docker Networking

As a virtual subnet, a Docker or Rocket container network is a type of SDN (Software Defined Network).

Separating the Docker subnet from the underlying network hardware is extremely important. It allows entire container networks to migrate between platforms, including from private to public clouds, without modification. Container networks can span multiple platforms — for example, principal services can run on-premises, while overflow containers can be instantiated on a public cloud, such as Amazon Web Services (AWS). This increases efficiency and allows for consistent bandwidth and application performance, even during peak network demand points.

The Docker platform was designed to simplify the building of distributed applications (applications made of multiple containers) so they could run more efficiently in the cloud. All of Docker’s basic composition, distribution, scheduling, and deployment components can be used with simple commands, typed into an ordinary command-line interface (CLI). Originally, Docker was an open-source project made by dotCloud, designed to be a simple mechanism for deploying workloads on dotCloud’s platform-as-a-service (PaaS) platform.

Introduction of Kubernetes

Kubernetes was introduced to the open-source community by Google in 2014 and quickly gained popularity as a way to simplify container management. Containerized applications would easily get out of control with how many containers are created and their relationship to each other. Kubernetes is also capable of scaling automation, maintaining storage across application instances, load balancing, and restoring failed containers.

In further articles, we will understand the Docker platform core components, configuration, orchestration, and plugins. Till then stay safe and happy learning with Learnizo Global.