An Overview of Docker

What is Docker ?

Docker is an open source software platform to create, deploy and manage virtualized application containers on a common operating system (OS), with an ecosystem of allied tools. Docker enables you to separate your applications from your infrastructure so you can deliver software quickly. With Docker, you can manage your infrastructure in the same ways you manage your applications.

What can I use Docker for?

Responsive deployment and scaling

Docker’s portability and lightweight nature also make it easy to dynamically manage workloads, scaling up or tearing down applications and services as business needs dictate, in near real time.

Running more workloads on the same hardware

Docker is lightweight and fast. It provides a viable, cost-effective alternative to hypervisor-based virtual machines, so you can use more of your compute capacity to achieve your business goals. Docker is perfect for high density environments and for small and medium deployments where you need to do more with fewer resources.

The Docker platform

Docker provides the ability to package and run an application in a loosely isolated environment called a container. The isolation and security allows you to run many containers simultaneously on a given host. Containers are lightweight and contain everything needed to run the application, so you do not need to rely on what is currently installed on the host. You can easily share containers while you work, and be sure that everyone you share with gets the same container that works in the same way.

Docker provides tooling and a platform to manage the life cycle of your containers:

• Develop your application and its supporting components using containers.
• The container becomes the unit for distributing and testing your application.
• When you’re ready, deploy your application into your production environment, as a container or an orchestrated service. This works the same whether your production environment is a local data center, a cloud provider, or a hybrid of the two.

What is a container?

A container is a runnable instance of an image. You can create, start, stop, move, or delete a container using the Docker API or CLI. You can connect a container to one or more networks, attach storage to it, or even create a new image based on its current state. When a container is removed, any changes to its state that are not stored in persistent storage disappear.

By default, a container is relatively well isolated from other containers and its host machine. You can control how isolated a container’s network, storage, or other underlying subsystems are from other containers or from the host machine.

Docker containers provide a way to get a grip on software. You can use Docker to wrap up an application in such a way that its deployment (deployment means making an application ready for delivery.) and runtime issues; how to expose it on a network, how to manage its use of storage and memory and I/O, how to control access permissions are handled outside of the application itself, and in a way that is consistent across all “containerized” apps. You can run your Docker container on any OS-compatible host (Linux or Windows) that has the Docker runtime installed.

Docker offers many other benefits besides this handy encapsulation, isolation, portability, and control. Docker containers are small (megabytes). They start instantly. They have their own built-in mechanisms for versioning and component reuse. They can be easily shared via the public Docker Hub or private repository.

What is an orchestration system?

Orchestration System — provides automated configuration, coordination and management of complex computing networks, systems and services.

What exactly is Kubernetes?

Kubernetes is a portable, extensible, open-source platform for managing containerized workloads and services which facilitates both declarative configuration and automation. It has a large, rapidly growing ecosystem

Kubernetes is an example of a container management system developed in the Google platform. The biggest advantage of using Kubernetes is that it can run on-premises OpenStack, public clouds Google, Azure, AWS, etc. Kubernetes offers automated Scheduling and Self-Healing Capabilities.

Docker vs Kubernetes:

A fundamental difference between Kubernetes and Docker is that Kubernetes is meant to run across a cluster while Docker runs on a single node. Kubernetes is more extensive than Docker Swarm and is meant to coordinate clusters of nodes at scale in production in an efficient manner.

Resource: https://docs.docker.com/

The bottom line:

Kubernetes and Docker are both industry standards in their respective core areas of expertise, and together they provide a well-integrated platform for container management, deployment, and orchestration at scale.

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