Pre-requisites: Kubernetes, Docker
Docker is a platform for containerization, while Kubernetes manages containers for numerous container runtimes. There are various container runtimes supported by Kubernetes. Some are
- Docker
- Containers
- CRI-O
- Mirantis Container Runtime
What are Containers?
Container package application software with their dependencies in order to abstract from the infrastructure it runs on. Now containers basically offer a logical packaging mechanism in which applications can be abstracted from the environment in which they actually run. Now, this decoupling allows container-based applications to be deployed easily and consistently regardless the target environment is a private data center, the public cloud even a developer’s personal laptop.
What is Kubernetes?
Kubernetes is a container management system developed in the Google platform(GO Language). It helps you to manage a containerized application in various types of physical, virtual, and cloud environments. Google Kubernetes is a highly flexible tool to deliver even complex applications consistently. Applications run on clusters of 100 to 1000 individual services.
Key Feature of Kubernetes
It has a tremendous amount of features which are as follows.
- Runs everywhere: It is an open-source tool and gives you the freedom to take advantage of on-premises, Public & hybrid cloud infrastructure letting you move your workload anywhere you want.
- Automation: For instance, Kubernetes will control for you with a servable host of the container that will be launched.
- Interaction: Kubernetes is able to manage more clusters at the same time. & It allows not only horizontal but even vertical scaling also.
- Additional services: It provides additional features as well as the management of containers, Kubernetes offers security networking & storage services.
- self-monitoring: It also gives you a provision of self-monitoring as it constantly checks the health of nodes and the container itself.
Kubernetes Advantages
- Automatic container schedule: Kubernetes may reschedule a container from one node to another to increase resource utilization. This means you get more work out of the same number of machines, which saves money.
- Service discovery: When you have a bunch of services that need to communicate with each other it’s critical that they are able to find each other first. This is especially true because containers are automatically scheduled and may potentially get moved around. Thankfully, Kubernetes makes it easy for containers to communicate with each other.
- Self-Healing: Kubernetes automatically monitors containers and reschedules them if they crash or are terminated when they shouldn’t. Kubernetes will also reschedule containers in the event that the node that they’re living on fails.
- Rolling Upgrades: Fortunately, Kubernetes has the ability to perform rolling updates. This is where old containers are judiciously swapped out of a new version of the same containers all without disrupting the service provided by the running application.
Kubernetes Disadvantages
- Steep learning curve: Kubernetes is not an easy platform to learn, even for the most experienced developers and DevOps engineers.
- Install & configure: Kubernetes consists of multiple no. of components that should be configured and installed separately to initialize the cluster. if you install Kubernetes manually you should also configure the security which includes creating a certificate authority & issuing the certificate
- No high availability: Kubernetes does not provide high availability mode by default to create a fault-tolerant cluster you have to manually configure HA for your ETCD cluster.
- Compatibility issues: Sometimes when you have containers you may need to use Docker with communities. But at that time communities were not compatible with existing Docker CLI and composing tools. And it requires more effort during the migration whenever you have to migrate to a stateless It actually requires many efforts.
What is Docker?
Docker is a platform used to containerize your software, using which you can easily build your application, the package with the dependencies required for your application into the container further, these containers are easily shipped to run on other machines. Docker is simplifying the DevOps methodology by allowing developers to create templates called images using which you can create a lightweight, virtual machine called a container.
Docker is making things easier for software industries giving them the capabilities to automate the infrastructure, isolate the application, maintain consistency, and improve resource utilization.
Key Feature of Docker
- Easy configuration: This is one of the key features of Docker in which you can easily deploy your code in less time & effort as you can use Docker in a wide variety of environments. The requirement of the infrastructure is no longer linked with the environment of the application helping in configuring the system easier and faster.
- You can use swarm: It is a clustering and scheduling tool for Docker containers, SO swarm used the Docker API as a frontend which helps us to use various tools to the controller, it also helps us to control clusters for Docker host as a single virtual host, it is a self-organizing group of engines that is used to enable, pluggable backbends.
- Manages security: Docker allows us to save secrets in the swarm itself. And then choose to give services access to certain secrets. It includes some important commands to the engine like secret inspection, secretly creating, etc.
- Services: Service is a list of tasks that lets us specify the state of a container inside of a cluster. Each task represents one instance of a container that should be running and Swan schedules them across the nodes.
- More Productivity: By easing technical configuration & rapid deployment of applications no doubt it has increased productivity, Docker not only helps to execute the application in an isolated environment but also reduces the resources also.
Docker Advantages
- Build app only once: An application inside a container can run on a system that has Docker installed. So there is no need to build and configure apps multiple times on different platforms.
- More sleep and less worry: With Docker, you test your application inside a container and ship it inside a container. This means the environment in which you test is identical to the one on which the app will run in production
- Portability: Docker containers can run on any platform. It can run on any local system, Amazon EC2, Google Cloud, Virtual Box, etc.
- Version control: Like git, Docker has a built version control system. Docker containers work just like GIT repositories, allowing you to commit changes to your Docker images and version control them.
Docker Disadvantages
- Missing feature: It has got Missing features. There are tons of features that are under progress like container self-registration, self-inspect copying files from host to container, and many more.
- Data in the container: When the container is going down after that it needs a backup and recovery strategy although we have several solutions for that they are not automated or not very scalable yet.
- Graphical app: Docker was designed as a solution for deploying server apps that do not require a graphical interface, while there are some creative strategies such as x11 video forwarding that u can use to run GUI apps inside the container.
- The benefit is few: Generally, only apps that are designed to run as a discrete set of microservices stand to gain the most from containers, otherwise, Docker’s only real benefit is that it can simplify application delivery by providing an easy package machinima.
Docker or Kubernetes: Which one is right for you?
When compared to Kubernetes, Docker takes less setup and configuration. For example, you may deploy your application using YAML files, automatically achieve the appropriate state, load balance amongst containers in the cluster, and provide security and access control for your services. If the burden is not heavy, choosing Docker Swarm instead of Kubernetes is a smart option.
The initial setup of Kubernetes is more difficult, but it has a lot of functionality. We can manage network ingress and observability with kubernetes. The majority of cloud platforms offer Kubernetes as services like EKS, AKS, and GKS, allowing Kubernetes to benefit from functions like autoscaling, load balancing, etc. The pods and containers that are deployed in Kubernetes can be segregated with the use of a namespace. If you want high security and excellent availability, Kubernetes is a fantastic option.
Using Kubernetes with Docker
Kubernetes will serve as a container orchestration tool when used with Docker, and Docker will assist us in creating the images needed to execute containers in Kubernetes. All container deployments, scaling, and scheduling to the correct node in the cluster may be handled by Kubernetes.
Kubernetes vs Docker
|
Kubernetes |
Docker |
|---|---|
| Kubernetes is an open-source platform used for maintaining and deploying a group of containers | Docker is a tool that is used to automate the deployment of applications in lightweight containers so that applications can work efficiently in different environments. |
| In practice, Kubernetes is most commonly used alongside Docker for better control and implantation of containerized applications. | With Docker, multiple containers run on the same hardware much more efficiently than the VM environment & productivity of Docker is extremely high. |
| Applications are deployed as a combination of pods, Deployment, and services. | Apps are deployed in the form of services. |
| It supports auto-scaling of the container in a cluster. | Docker does not support auto-scaling. |
| The health check is of two kinds: liveness and readiness. | Health checks are limited to service. |
| Hard to set up and configure. | Docker’s setup and installation are easy. |
| It does not have extensive documentation but is quite less than Docker. But it does include everything from installation to deployment. | Docker documentation is more effective, more extensive, and has even more capabilities & it includes everything from installation to deployment & quick-start instructions as well as a more detailed tutorial. |
| Kubernetes installation is provided to be quite difficult than Docker and even the command for Kubernetes is quite more complex than Docker. | Docker installation is quite easier, by using fewer commands you can install Docker in your virtual machine or even on the cloud. |
| Azure, buffer, intel, Evernote, and Shopify Using Kubernetes. | Google, Amazon, ADP, VISA, citizens bank, and MetLife companies using Docker. |
Master DevOps with industry experts to streamline your workflow and deliver high-quality software rapidly. Checkout: DevOps Engineering – Planning to Production