To be successful in cloud native development, developers must be familiar with Kubernetes and Docker. Here are some fundamentals about these two container technologies.
Containers and microservices have emerged as the most popular enterprise technology. This is especially true if your firm has implemented CI/CD and DevOps technologies or is striving to become more nimble in an increasingly competitive environment.
When it comes to containerization, Kubernetes and Docker are at the top of the list. Although these DevOps tools are on distinct paths, Kubernetes and Docker are at the forefront of the containerization trend, and you most likely have, are, or will use one or both.
Companies profit from containers because they offer:
- deploying and creating applications in an agile manner
- Software for CI/CD DevOps Observability
- OS portability and the cloud
- Management focused on applications
- the true isolation of resources
Which of these DevOps tools—Kubernetes or Docker—is most suitable to your company’s requirements and your DevOps workflow? Let’s investigate.
What is Kubernetes?
Your containerized apps and microservices may be managed, automated, and scaled using Kubernetes, an open-source container orchestration platform. The Cloud Native Computing Foundation is now in charge of maintaining Kubernetes, which was initially created by Google.
Not only single containers, but rather massive containerized deployments are what Kubernetes is all about. In order to manage the resources of the nodes connected to the cluster, Kubernetes can be installed on a cluster of bare metal servers in your data centre or on the clouds of other companies. Although it’s not optimised to manage more than 500 nodes per cluster, a cluster can be made up of a controller and one node or a controller and as many as 5,000 nodes.
Docker was once Kubernetes’ runtime engine of choice. This is no longer the case, and Kubernetes now supports runtime engines like Podman and containerd.
What is Docker?
A single container can be deployed using Docker to either a solitary server or a cluster known as a Docker Swarm. This is not to say that Docker cannot operate with larger deployments; the Swarm mode makes it feasible to set up a cluster of Docker nodes and scale the deployment of your containerized software and microservices.
The fact that Docker has a considerably more manageable learning curve than Kubernetes is a key feature. Start with Docker and move up to Kubernetes if you’re looking to dive into the realm of containers.
Comparison of Kubernetes vs Docker side by side
Container management and deployment are handled by Kubernetes and Docker. By default, Kubernetes functions as a node cluster where the containerized application can be scaled as necessary. A container runtime engine called Docker can deploy a single container to a single node and full-stack apps to a cluster as well (called a Docker Swarm).
While Kubernetes focuses on containerized applications at scale, Docker is primarily concerned with creating, sharing, and operating individual containers.
Controllers and nodes
Although the deployment of controllers and nodes is not necessary for the usage of Docker, it is necessary if you intend to use Docker Swarm.
The use of controllers and nodes is necessary for Kubernetes. AWS, Azure, Google Cloud, Rackspace, and Linode are just a few examples of third-party cloud providers that can host these controllers and nodes, but they can also be standard servers in your data centre.
You have access to all the tools you need to create containerized apps with Kubernetes and Docker. Both DevOps approaches layout portable, containerized apps using JSON-formatted manifests and rely on image registries (such those found on sites like Docker Hub). For development, Kubernetes and Docker include a number of third-party GUI tools in addition to command-line interface tools.
Your current development tools, such as your preferred IDEs and versioning systems like git, can be integrated with Kubernetes and Docker.
Clusters can be used by both Kubernetes and Docker, but Kubernetes requires a cluster whereas a Docker Swarm is optional. This also emphasises how Kubernetes scales much more easily and broadly than Docker, which is the biggest distinction between the two technologies.
The likelihood that a containerized application you deploy will rely on previously stored data is high. Thankfully, persistent volumes can be used with Kubernetes and Docker. These volumes store data externally so that, in the event that something were to happen to the running containers, the data would still be preserved in a persistent volume.
Data sharing between containers is also made possible via persistent volumes. For instance, you could use a persistent volume to launch a MySQL container, and then link different containers to the database.
Containers and pods
Applications and microservices that are containerized are deployed by Docker. Pods, a higher-level structure that can contain several containers sharing the same resources, are actually how Kubernetes wraps containers. A single pod shouldn’t have too many containers deployed on it because they must scale simultaneously, which could waste resources.
Although Docker doesn’t support pods, full-stack applications can still be deployed using separate but connected containers.
Networking is one area where Docker really excels. With Docker, deploying containers is simple, and they can be quickly and readily accessed over a network.
Pods are cut off from the outside world by Kubernetes. To access such containerized applications from outside the cluster, you must add an Ingress controller or load balancer.
Docker and Kubernetes feature comparison
|Monitoring||Built-in||Third-party tools are required.|
|Runtime engine||Requires third-party tools||Built-in|
|Clustering||Built-in||Cluster mode deployment is required (Docker Swarm)|
|Recommended node size||500 maximum nodes||Maximum of seven manager nodes are advised for a swarm.|
Choosing Kubernetes vs. Docker
If you want to get started with containerized applications and microservices, Docker is a great place to start. And, once again, if you only want to deploy a single container to a single node or a tiny cluster, Docker is your best bet. If you’re a larger company looking to deploy containerized applications at scale, Kubernetes is the way to go.