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“Kubernetes vs. Docker” is a phrase that you hear more and more these days as Kubernetes becomes ever more popular as a container orchestration solution.
However, “Kubernetes vs. Docker” is also a somewhat misleading phrase. When you break it down, these words don’t mean what many people intend them to mean, because Docker and Kubernetes aren’t direct competitors. Docker is a containerization platform, and Kubernetes is a container orchestrator for container platforms like Docker.
This post aims to clear up some common confusion surrounding Kubernetes and Docker, and explain what people really mean when they talk about “Docker vs. Kubernetes.”
Kubernetes vs Docker: The Rise of Containerization and Docker
It is impossible to talk about Docker without first exploring containers. Containers solve a critical issue in the life of application development. When developers are writing code they are working on their own local development environment. When they are ready to move that code to production this is where problems arise. The code that worked perfectly on their machine doesn’t work in production. The reasons for this are varied; different operating system, different dependencies, different libraries.
Containers solved this critical issue of portability allowing you to separate code from the underlying infrastructure it is running on. Developers could package up their application, including all of the bins and libraries it needs to run correctly, into a small container image. In production that container can be run on any computer that has a containerization platform.
Kubernetes vs Docker: Advantages of Containers
In addition to solving the major challenge of portability, containers and container platforms provide many advantages over traditional virtualization.
Containers have an extremely small footprint. The container just needs its application and a definition of all of the bins and libraries it requires to run. Unlike VMs which each have a complete copy of a guest operating system, container isolation is done on the kernel level without the need for a guest operating system. In addition, libraries can be across containers, so it eliminates the need to have 10 copies of the same library on a server, further saving space. If I have 3 apps all running node and express, I don’t have to have 3 instances of node and express, those apps can share those bins and libraries. Allowing for applications to become encapsulated in self-contained environments allows for quicker deployments, closer parity between development environments, and infinite scalability.
Docker vs Kubernetes: The Need for Orchestration Systems
While Docker provided an open standard for packaging and distributing containerized applications, there arose a new problem. How would all of these containers be coordinated and scheduled? How do you seamlessly upgrade an application without any interruption of service? How do you monitor the health of an application, know when something goes wrong and seamlessly restart it?
Solutions for orchestrating containers soon emerged.Kubernetes,Mesos And Docker Swarm are some of the more popular options for providing an abstraction to make a cluster of machines behave like one big machine, which is vital in a large-scale environment.
The truth is that containers are not easy to manage at volume in a real-world production environment. Containers at volume need an orchestration system.
What does an orchestration system need to do? Among other things, it must:
- Handle a large volume of containers and users, simultaneously. An application may have thousands of containers and users interacting with each other at the same time; managing and keeping track of these interactions requires a comprehensive overall system designed specifically for that purpose.
- Manage service discovery and communication between containers and users. How does a user find a container and stay in contact with it? Providing each microservice with its own, built-in functions for service discovery would be repetitive and highly inefficient at best; in practice, it would be likely to lead to intolerable slowdowns (or gridlock), at scale.
- Balance loads efficiently. In an ad-hoc, un-orchestrated environment, loads at the container level are likely to be based largely on user requirements at the moment, resulting in highly imbalanced loads at the server level, along with logjams resulting from the inefficient allocation and resulting limited availability of containers and system resources. Load-balancing replaces this semi-chaos with order and efficient resource allocation.
- Authentication and security. An orchestration system such as Kubernetes makes it easy to handle authentication and security at the infrastructure (rather than the application) level, and to apply consistent policies across all platforms.
- Multi-platform deployment. Orchestration manages the otherwise very complex task of coordinating container operation, microservice availability, and synchronization in a multi-platform, multi-cloud environment.
An orchestration system serves as a dynamic, comprehensive infrastructure for a container-based application, allowing it to operate in a protected, highly organized environment, while managing its interactions with the external world.
Kubernetes is well-suited to the task and is one of the reasons it has become so popular.
Kubernetes vs Docker Swarm
When most people talk about “Kubernetes vs. Docker,” what they really mean is “Kubernetes vs. Docker Swarm.” The latter is Docker’s own native clustering solution for Docker containers, which has the advantage of being tightly integrated into the ecosystem of Docker and uses its own API. Like most schedulers, Docker Swarm Provides a way to administer a large number of containers spread across clusters of servers. Its filtering and scheduling system enables the selection of optimal nodes in a cluster to deploy containers.
What is Kubernetes used for?
Kubernetes is the container orchestrator that was developed at Google which has been donated to the CNCF and is now open source. It has the advantage of leveraging Google’s years of expertise in container management. It is a comprehensive system for automating deployment, scheduling and scaling of containerized applications, and supports many containerization tools such as Docker.
For now, Kubernetes is the market leader and the standardized means of orchestrating containers and deploying distributed applications. Kubernetes can be run on a public cloud service or on-premises, is highly modular, open-source, and has a vibrant community. Companies of all sizes are investing in it, and many cloud providers offer Kubernetes as a service. Sumo Logic provides support for all orchestration technologies, including Kubernetes-powered applications.
