Kubernetes vs Docker: Which one to choose?

Tags: kubernetes, docker, appdevelopment
Published: 2020-04-14 07:23:38

Containers are critical to develop an application. They are expected to keep up consistency across platforms within the application development life cycle and hence, are gaining popularity among modern developers. Developers write code in local environments and then mode it to production. However, a code that worked fine on a developer’s machine probably won’t work the same way in production. The reasons are changed; it could be because of differences in operating systems, dependencies or libraries.

Here containers come into play. They simplify the portability of the code by allowing developers to separate it from the infrastructure it runs on. In other words, containers provide developers with more control over products compared with conventional means of virtualization. Because of their negligible footprint, they allow rapid development of applications and increased scalability. However, containers need to be coordinated and scheduled. The applications, of which they are a part, should be upgraded without problems or interferences. The strength of these applications should also be monitored. 

Hence Container orchestration is a significant procedure. In spite of the fact that the market has various solutions for the same, the most well known have been Kubernetes and Docker. The main difference is, Docker, behaves as a platform for containerization and Kubernetes a container orchestration system for Docker.

Here we will see a relative overview of the two seemingly different, but similar solutions and discover which is the best.

**What is Kubernetes?**


Kubernetes is an open-source container management software developed in the Google platform. It helps you to deal with a containerized application in different kinds of physical, virtual, and also cloud environments. It is a highly flexible tool to deliver complex applications. Applications ‘run on clusters of hundreds to thousands of individual servers.” It also allows you to deal with your containerized application all the more proficiently.

*Components of Kubernetes Clusters-*
**Pods:** Container groups placed on the same node, Pods in Kubernetes Clusters are created, scheduled and also deployed together.

**Services:** Used for Pod group nomenclature, Services in Kubernetes clusters act as load balancers for traffic to be directed to run containers.

**Replication Controllers:** Purpose intended to ensure a specific number of Pod replicas in Kubernetes clusters are scheduled and running, Replication Controllers are the basic framework in the system.

**Marks:** Key-value tags, labels are assigned to Pods, Services, and also Replication Controllers in Kubernetes clusters to identify the same.

**Features of Kubernetes–**
Kubernetes has been known to be a complicated containerization tool. However, the equivalent has been rendered simple and user friendly by means of various upgrades in recent times. The software isn’t equipped for version control, simpler application distribution and also deployment.

*Below are the Kubernetes features worth mentioning:*

1. Application-centric management
2. Self-Healing capabilities
3. Offers automated scheduling
4. Horizontal Scaling & Load Balancing
5. Automated rollouts & rollback
6. Provides a higher density of resource utilization
7. Offers enterprise-ready features
8. Auto-scalable infrastructure
9. You can create predictable infrastructure
10. Provides declarative configuration
11. Deploy and update software at scale
12. Offers environment consistency for development, testing, and production

**What are the Pros and Cons of Kubernetes?-**
Here are the top benefits and drawbacks of using Kubernetes container:

**Pros of Kubernetes:**
1. Open-source and customizable
2. Reliable, since developed by Google
3. Runs on any operating system
4. Simplified organization of Service using Pods
5. Container orchestration tool with the largest community
6. Multiple storage options including on-prem SANs and public clouds
7. Upholds immutable infrastructure principles

**Cons of Kubernetes:**
1. Migration to stateless is complicated
2. Functionality is limited and depends on Docker API availability
3. Installation and configuration is complicated
4. Incompatible with existing Docker tools
5. Cluster deployment is manual and complex
6. Set up of automatic horizontal scaling is complicated

**What is Docker?**

Docker is an open-source lightweight containerization technology. It has gained noticeable popularity in the cloud and also application packaging world. Docker allows you to automate the deployment of applications in lightweight and portable containers too. It is computer software used for Virtualization. It also allows you to run different Operating systems on a similar host. Virtualization in Docker is performed on the system-level in what is popularly called Docker containers.

The most important aspects to know about Docker are as follows:

*Docker Engine –* the runtime needed to build and run application containers.

*Docker File –* used to build a Docker container to be run using a Docker Engine. It has all the things expected to run a Docker Image including network specifications of the operating system and file locations.

*Docker Image –* a static and portable component built using a Docker File which runs on the Docker Engine

*Docker Hub –* a Docker service that allows you to store and share Docker Images

**Components of Docker Swarm–**
*Manager Nodes:* In a Docker Swarm, Manager Nodes incorporate Control Orchestration, Task Distribution, and Cluster Management.

*Worker Nodes:* Functions in a Worker Node in Docker Swarm include running the containers and services the Manager Node assigns.

*Services:* These components in a Docker Swarm include the blueprint description required by discrete containers to distribute themselves across nodes.

*Tasks:* Single containers in a Docker Swarm place their work on slots known as Tasks.

**Features of Docker–**
The software has been developed on these four cornerstones:

1. Docker Universal Control Panel that acts as a single interface to deliver powerful UX
2. A single failure point to form a resilient architecture
3. Existing components with backward compatibility
4. Auto-generated certificated for security

Based on its built-up, Docker comes with the following essential features:

Isolated environments for application management
Ease of modeling and version control
Placement and Affinity
Agility of applications
Productivity for developers
Operational efficiency
Pros and Cons of Docker–
Here are significant benefits and drawbacks of using Docker container:

**Pros of Docker:**
1. Open-source software
2. Initial set up easy and uncomplicated
3. Supports existing tools
4. Lightweight installation
5. The application life cycle can be described in detail
6. Easy container version tracking
7. Discrepancy identification between prior versions
8. Docker Compose for simple configuration
9. Quick booting of a virtual machine
10. Speedy running of app in a virtual environment
11. Documentation for detailed information
12. Isolated application

*Cons of Docker:*
1. No storage option
2. Basic infrastructure handling is complicated
3. Monitoring option is not up to mark
4. Automatic rescheduling of inactive nodes not possible
5. Automatic horizontal scaling set up is complicated
6. Every action needs to be performed in CLI
7. Production, monitoring, healing, and scaling requires support from other tools
8. Cluster deployment is manual and complicated
9. Health checks not supported
10. Critical components such as Docker Engine and Docker Desktop are not open-source


**Differences between Kubernetes and Docker-**
Both the container orchestration tools have been developed to confine hardware use and save resources. Both are immensely useful with regards to business resource management. However, Kubernetes and Docker show some differences that can’t be neglected. Let’s know them.

*Installation and Cluster Configuration-*
Kubernetes installation is relatively simple in a test bed. However, running it at scale would require some more effort. On the other hand, Docker use CLI to run programs. It tends to be configured using a single set of tools.

*Container Building and Running-*
Kubernetes accompanies its own API, YAML definitions and also client, which are way above their standard Docker equivalents. However, new containers can be built using a single command of one Docker CLI.

*Logging and Monitoring-*
Kubernetes accompanies built-in tools for logging and monitoring to analyze failures by past logs and keep an eye on the strength of containerized nodes. Docker doesn’t have this ability due to the lack of built-in tools. Rather, it uses a third-party for the same.

*Scalability-*
Kubernetes is a superior choice with regards to the strength maintenance of clusters. Yet, it is complex owing to the set of APIs it has. Nevertheless, it is great for auto-scaling as it can analyze server load and scale up or down as per requirements.

On the other hand, Docker allows higher scalability than Kubernetes. Deployment of containers is rapid through single update command, particularly for larger clusters. Also, auto-scaling is effective and hence, traffic handling is simpler.

*Load Balancing-*
Kubernetes needs to define Container Pods as Services to allow Load Balancing. Also, manual configuration of settings is required. Further, just certain Pod sets offer access to Services. Docker, accompanies built-in features for Load Balancing. This includes a common network where containers of the same cluster join, in this way allowing connections of all nodes to all containers.

*Graphical User Interface-*
Kubernetes is best for those who are fussy about dashboards. To control clusters, GUI can be used without limitations. This is particularly useful when you are not technically knowledgeable. On the other hand, Docker allows simple management of UI using third-party tools.

**Which is Better – Kubernetes or Docker?**
From this analysis, obviously Kubernetes is a superior container orchestration solution compared to Docker. The latter lags behind with regards to satisfying the demands of the open-source community. Kubernetes has nailed it and proceeds to rapidly develop with positive updates.

It isn’t only functionally better, but also technically more advanced than Docker. Kubernetes allows better strength checking at Pod level alongside more effective container scheduling and scaling. It offers Namespaces with role-based access controls. It’s network policies for ingress and egress traffic control makes it a favorite with users.