These are two important fundamental tools required in the deployment of apps. Docker is a containerization platform, whereas, Kubernetes is a container orchestration platform. These two are best when they work together in migrating the infrastructure of a business to cloud-native in containers.
What is Docker?
Docker is a platform which enables the delivery of softwares as a service product, using OS-level virtualization, in different packages which are known as containers. It runs applications in an isolated environment. It is because of the isolation, that several containers can run simultaneously with just one host. The virtual machines can also help the run time of the Docker machines. It works on a client-server architecture allowing the user to develop, collect, ship an application and control its execution in a safe environment.
Look at the components of the Docker engine:
- REST API
- Command Line Interface
- Docker Daemon
Running on one system only, Docker client and Docker Daemon (server) can possibly work together. Take a look at the architecture of Docker:
- Docker client: It is the first and the most important route that helps the users interact with the docker and can simultaneously communicate with a number of Daemons (servers). All a user has to do is to run the command, which transfers them to the server, taking the process further.
- Docker Daemon: This is the server that runs through the requests received on the APIs. This enables a Demon communicate with other Deamons and manage the objects listed under it such as networks, volumes, images and the containers as well.
- Docker registries: It is a system that stores the Docker images and does their distribution as well. Take a look at the functions performed by Docker registries:
- It is able to store various tags for a single image.
- It can store a large number of images, irrespective the size of the image.
- The push and pull functions of the registries is done through HTTP API on the Docker registries.
- It has a secured connection of TLS to avoid any sort of digital or manual attacks.
- Docker objects: These are basically the elements that can be created using Docker. The list of these elements includes the likes of plugins, containers, volumes, images, networks and more.
What is Kubernetes?
It is fundamentally an open-source container-orchestration for managing services that are in containers. It operates Linux container operations and gather the groups in an organized manner. It is also responsible to take care of the health of these containers.
An overview of the architecture of Kubernetes
There are two important fundamental concepts that bear an association with Kubernetes. One of the two concepts is the Pod and the other one is the Node. Node is the metal servers that is managed by Kubernetes along with other virtual machines. On the other hand, Pod is an amalgamation of associated Docker containers that have a coexistence.
Now, take a look at the architecture of Kubernetes:
- Kubernetes API server: Manageable by the humans these are API servers that divulge the levers and gears of the Kubernetes. It has a direct interaction with the clusters of Kubernetes.
- Kubernetes controller manager: The information on the current situation of the clusters is shared by the Kube-controller manager, which then retrieve this information and help in making important decisions on how to achieve the goal required.
- Kubernetes scheduler: One of the core components of the Kubernetes, this helps in exposing the container orchestration and the interfaces, which manage the life cycle of the containers. The events are arranged through the help of this function, which further depends upon the standards, convenience and permissions of the operator. It also helps in acquiring the cluster’s state of work with the help of Kube-Episerver.
- Etcd: It is a stack used for saving, used by the master node. App developers and software developers can use this feature to store work secrets, state of the cluster and policies of the organization.
Comparison between a Docker and Kubernetes
There are several topics that can help us differentiate between the two. Keep reading to get a better understanding of how they work:
- Scalability: With a total of 5000 node clusters and 1,50,000 pods, Kubernetes are a highly scalable. On the contrary Docker has more than 1,000 nodes and 30,000 pods.
- Installation and configuring the cluster: Kubernetes are more complex to install than Decker, but result delivered by the former is much stronger and vigorous than the latter.
- Availability: Kubernetes are highly available as their health check performance on the nods is direct. In the case of Docker, the function is restarted if it encounters a failure at the host level. It gets transferred to another host and performs the functions there.
- Balancing the load: The traffic between the various pods on Kubernetes sometimes need manual load balancing, however, Docker is enables to manage the load automatically without the involvement of humans.
- Container updates: The upgrades in Kubernetes are included with automated rollbacks, similarly Docker also has automatic rollbacks with Docker 17.4 or higher.
- Networking: Kubernetes do all the networking of the containers virtually with the help of flannel, while Docker brings consistency among containers on several nods by forming a multiple-host access network overlay.
- Data volumes: These enable data sharing in a particular pod in the case of Kubernetes, whereas, Docker can share directories of data between one particular pod of different pods.
There are several beliefs pertaining to the working of Kubernetes and Docker. These are both efficient, however, they are different in their fields and their services vary from one another. Let’s look at some myths that follow these two deployment platforms:
- Can Docker be used with Kubernetes?
Docker is mostly used without Kubernetes in the deployment stage as the latter becomes more expensive to use if the complexities increase during the development phase.
- Can Kubernetes be used without Docker?
Most of the people might know of this, but let us also inform you how this works. Kubernetes need container runtime essentially to orchestrate in the deployment phase, therefore it needs the work of Docker as well. However, Docker can be replaced by any other container runtime as well, such as Ruc C or cri-o.
Need to shift towards Kubernetes
Most software developing companies are moving towards cloud architectures using containers, one needs to have a platform that is more trustworthy and has passed through tests.
Take a look at the reasons why people are moving towards Kubernetes:
- It utilizes the resources well than the Virtual machines do the same, at the same time it is cost-effective as one does not have to incur a lot of expense on it.
- Any business that uses Kubernetes works faster as it is equipped with Platform-as-a-Service (PaaS).
- It can be run on multiple platforms including Amazon Web Services, Microsoft Azure and on Google Cloud.
Setbacks for Docker:
- There is not option for storing the data
- Health checks cannot be performed on Docker
- It uses the command line interface
- The monitoring capabilities are poor
- The deployment can only be monitored manually, and is usually complex
We have thrown light on the uses of Kubernetes and Docker in making an application and transferring it to the receiver before actually deploying it. The users are now well versed with the functioning of the two and the differences that have clearly stated the features that make them work in separate algorithms. This material is for those who are thinking of getting started with the two platforms. A better software can be made by mastering on the two platforms and understanding how they work. Comparing the two, it is easier for the software producers to start by working on Docker, to get a better understanding without much complexities. For individuals and firms who want a faster deployment, the simpler platform Docker should be used, than getting into the intricacies of Kubernetes.
Both the platforms are going to perform well in the long run, however, the pros and cons for both should be monitored well before making the final decision on which platform to use. Once should consider all the aspects before performing the deployment activities of their softwares. These are accompanies with a dozen of benefits.