Why To Use Kubernetes When We Already Have Dockers in 2024?

Using Kubernetes and Docker offers several advantages, particularly for scaling, managing, and orchestrating containerised applications.

To know the answer to the question-“Why To Use Kubernetes When We Already Have Dockers?“, we need to know what exactly are Docker and Kubernetes so that we all are on the same page and can learn things efficiently.

What is a Docker?

Docker is a containerisation platform used to package applications, along with their dependencies, libraries, and everything else they need, into software containers. These containers can then be deployed consistently across various environments, regardless of the underlying operating system. This consistency is one of the key advantages of containerization.

In simple terms, a container is a lightweight, standalone, and executable package that includes everything needed to run a piece of software. It operates as an isolated process on the host operating system, utilizing kernel features to provide an environment that mimics a full operating system within a directory, rather than deploying a full-fledged OS.

Benefits of Containers

Containers do not contain an entire operating system, which offers several significant benefits:

• Faster Boot-Up Process: Containers start much faster than virtual machines because they do not need to boot an operating system.
• Less Resource Utilization: Containers share the host system’s kernel and resources, leading to more efficient use of system resources.
• Smaller Image Size: Without the need to include an entire operating system, container images are much smaller, making them quicker to transfer and deploy.

Docker’s containerization provides a consistent and efficient way to develop, deploy, and run applications, with the added benefits of faster startup times, reduced resource usage, and smaller application packages.

Now, let’s quickly talk about Kubernetes and its needs.

What is Kubernetes (K8)?

Kubernetes is an open-source container orchestration tool to orchestrate the deployment and management of containerized applications, handling tasks such as scaling, load balancing, and resource allocation.

Why To Use Kubernetes When We Already Have Dockers?

There were many challenges with Docker as stated below:

1. Single Host Nature: Docker operates on a single host, which can lead to resource contention. For example, if Container C1 consumes a large amount of memory, other containers may suffer and be killed by the Linux kernel due to resource constraints.
2. Lack of Auto-Healing: Docker does not provide automatic recovery mechanisms. If a container is killed or crashes, it must be manually restarted. Managing thousands of containers manually is impractical and can lead to downtime. Role-Based Access Control (RBAC): Kubernetes provides fine-grained control over access to resources, ensuring that users and applications have only the permissions they need.
3. No Auto-Scaling: Docker lacks built-in auto-scaling capabilities. When application demand spikes, such as during a popular movie release, manual intervention is required to scale up the number of containers to handle the increased load and to perform load balancing.
4. Enterprise-Level Features: Docker lacks enterprise-level features such as load balancing, advanced networking, security, auto-scaling, auto-healing, and API gateways. These features are essential for large-scale production environments.

Kubernetes (K8s) addresses these challenges by using YAML files to define configurations, making it easier to manage complex environments. K8s operates as a cluster, a group of nodes, which helps solve the single host nature issue by distributing containers (pods) across nodes.

Kubernetes Features:

1. Cluster concept. Since K8 is a cluster of nodes, there is not a single point of failure due to resource contention.
2. Auto-Healing: Kubernetes has an auto-healing feature that automatically replaces containers that fail or die, ensuring high availability without manual intervention.
3. Auto-Scaling: Kubernetes uses replica sets to automatically scale the number of containers based on demand, ensuring applications can handle increased loads.
4. Enterprise-Level Standards: Kubernetes provides enterprise-level features such as load balancing, advanced networking, security policies, auto-scaling, auto-healing, and API gateways, meeting the requirements of large-scale deployments.
5. Rolling Updates and Rollbacks: It supports seamless updates to your application with zero downtime and allows you to roll back to previous versions if something goes wrong.
6. Role-Based Access Control (RBAC): Kubernetes provides fine-grained control over access to resources, ensuring that users and applications have only the permissions they need.

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