Kubernetes vs Docker: What are the Differences?

Date: 20-03-2024

Kubernetes vs Docker are two of the most popular containerization platforms developers use today. While Docker allows teams to package an application, its dependencies, and configuration together as a container image, Kubernetes enables the coordination and scheduling of multiple containers across numerous servers. 

The introduction of Docker in 2013 revolutionized computing by providing a modern containerization model based on microservices. However, as the complexity of applications increased with distributed containers, new challenges emerged that Kubernetes was designed to solve. 

Rather than focusing on which platform is better, it’s crucial to understand how you can leverage both Docker and Kubernetes to your advantage. By using Docker to package your application into a container and Kubernetes to manage and orchestrate those containers across multiple servers, you can achieve a scalable, loosely coupled architecture that facilitates the development of microservices.

Kubernetes vs Docker: What are they?

Docker is a commercial platform that facilitates containerization and runtime processes, which, in turn, assists developers in building, deploying, and running containers. The platform utilizes a client-server architecture that leverages simple commands and automation to enable users to interact with the system through a single API.

Docker further provides a toolkit that is widely used to package applications into immutable container images. This involves writing a Dockerfile and executing the necessary commands to build the image using the Docker server. While developers can create containers without Docker, the platform simplifies the process.

Container images generated via Docker can be deployed and executed on any platform that supports containers, including Kubernetes, Docker Swarm, Mesos, or HashiCorp Nomad. However, running and managing containers at scale can be challenging with Docker alone. Managing container coordination and scheduling across multiple servers/clusters, deploying or upgrading applications with zero downtime, and monitoring container health are some of the considerations that need to be addressed.

To address these concerns, solutions such as Kubernetes, Docker Swarm, Mesos, HashiCorp Nomad, and others emerged to orchestrate containers. These solutions enable organizations to manage numerous containers and users, balance loads efficiently, offer authentication and security, support multi-platform deployment, and more.

Kubernetes

Kubernetes, also known as K8s, is an open-source platform that manages container runtime systems across a network of resources. It is a highly popular tool that can be used with or without Docker. Initially, Google developed Kubernetes to run billions of containers at scale. The platform was released as open-source in 2014 and has become the industry standard tool for containers and application deployment. 

Kubernetes is designed to simplify the deployment and management of complicated distributed systems while taking advantage of the benefits of containerization. It groups containers running on the same machine to minimize network overhead and increase resource utilization efficiency. For instance, an app server, Redis cache, and SQL database can be bundled as one container set. 

Kubernetes is particularly useful for DevOps teams. It offers features such as service discovery, load balancing within the cluster, automated rollouts and rollbacks, self-healing of failed containers, and configuration management. It is an essential tool for building robust DevOps CI/CD pipelines. 

While Kubernetes is not a complete platform as a service (PaaS), it is a complex management tool. Many customers prefer using managed Kubernetes services from cloud vendors to handle the complexity of building and managing Kubernetes clusters.

Kubernetes Benefits

Kubernetes is a widely popular container orchestration platform that has been dubbed as the “Linux of the cloud”. Its powerful features and capabilities have gained immense popularity among developers and DevOps engineers. 

Automated operations

One of the primary reasons for its popularity is its ability to automate operations through a powerful API and command-line tool, called Kubectl, which makes container management a breeze. Kubernetes follows the controller pattern to ensure that applications and containers run precisely as specified.

Abstract infrastructure

Another significant advantage of Kubernetes is its ability to abstract infrastructure. It manages the resources available on your behalf, allowing developers to focus on writing application code instead of the underlying computing, networking, or storage infrastructure. This abstraction makes deploying applications in any environment easy, whether on-premises or in the cloud.

Service health monitoring

Kubernetes also excels at service health monitoring. It continuously monitors the running environment and compares it against the desired state. It performs automated health checks on services and restarts failed or stopped containers. Kubernetes ensures that services are only available when they are running and ready, ensuring maximum uptime and reliability.

Kubernetes vs Docker

Docker and Kubernetes are two of the most popular technologies in modern application development. While Docker is a container runtime, Kubernetes is a powerful platform for managing and running containers from multiple container runtimes. Kubernetes provides support for various container runtimes, including Docker, containers, CRI-O, and any implementation of the Kubernetes CRI (Container Runtime Interface). To put it simply, Kubernetes can be likened to an “operating system,” while Docker containers are the “apps” that run on the “operating system.”

Docker is a highly beneficial technology for modern application development, as it solves the classic problem of “works on my machine” but then nowhere else. Docker Swarm, a container orchestration tool, can handle the production container workload deployment of a few containers. However, standalone Docker can face some growing pains when the system needs to add many containers networked to each other, which is where Kubernetes comes in handy.

When comparing the two, it’s better to compare Kubernetes with Docker Swarm. Docker Swarm, or Docker swarm mode, is a container orchestration tool like Kubernetes and allows the management of multiple containers deployed across multiple hosts running the Docker server. However, Swarm mode is disabled by default and needs to be set up and configured by a DevOps team.

On the other hand, Kubernetes orchestrates clusters of machines to work together and schedules containers to run on those machines based on their available resources. Containers are grouped into pods, the basic unit of Kubernetes, through declarative definition. Kubernetes automatically manages things like service discovery, load balancing, resource allocation, isolation, and scaling your pods vertically or horizontally. The open-source community has embraced it and is now part of the Cloud Native Computing Foundation. Major cloud computing platforms such as Amazon, Microsoft, and Google offer managed Kubernetes services, significantly reducing the operational burden of running and maintaining Kubernetes clusters and their containerized workloads.

Read Also: Jenkins vs. Bamboo: Making the Right Choice for Your CI/CD Needs

Benefits of using Kubernetes and Docker

When used in conjunction, Kubernetes and Docker containers can provide organizations with many benefits in deploying and managing containerized applications at scale. 

Some of the key advantages of utilizing these tools include: 

Scalability

Kubernetes enables the scaling of containerized applications up or down as required, ensuring optimal performance resources are always available. This is particularly beneficial for applications that experience an upsurge in traffic or demand. 

High Availability

Kubernetes guarantees high availability of containerized applications by automatically restarting failed or terminated containers. This ensures smooth application operation and prevents downtime. 

Portability

Docker containers are portable and can be easily moved from one environment to another. This facilitates the seamless deployment of containerized applications across different infrastructures, including on-premises servers, public cloud providers, or hybrid environments. 

Security

Kubernetes secures containerized applications with role-based access control, network isolation, and container image scanning. This safeguards applications from unauthorized access, malicious attacks, and data breaches. 

Ease of Use

Kubernetes can automate the deployment, scaling, and management of containerized applications, saving organizations valuable time and resources while also reducing the risk of human error. 

Cost Reduction

Kubernetes and Docker can help organizations streamline IT operations costs by automating the deployment and management of containerized applications. 

Improved Agility

Kubernetes and Docker facilitate quicker deployment of new features and application updates, enabling organizations to be more agile. 

Increased Innovation

Kubernetes and Docker provide an easy-to-use and scalable platform to help organizations innovate more efficiently.

Kubernetes vs Docker: Which one is right for you?

Container orchestration platforms such as Docker Swarm and Kubernetes offer distinct advantages depending on the complexity of the infrastructure, the number of workloads running, and the desired features. Docker Swarm requires less setup and configuration than Kubernetes but offers similar benefits, such as declarative YAML file deployment, automatic scaling of services, load balancing, and security and access control over services. It is an excellent option for those who manage their infrastructure, have limited workloads, or do not require specific features offered by Kubernetes.

In contrast, Kubernetes is a more complex platform with a greater range of features and flexibility. It is supported by an active open-source community and provides various deployment strategies out of the box, network ingress management, and observability into containers. Major cloud vendors offer managed Kubernetes services that make it easier to get started and leverage cloud-native features, like auto-scaling. Kubernetes is suitable for organizations with multiple teams that require cloud-native interoperability, greater isolation of services, and many workloads to run efficiently.

Ultimately, the choice of container orchestration platform depends on the organization’s specific needs. By weighing the benefits and drawbacks of each platform, you can make an informed decision that meets your business goals and requirements.