Kubernetes and Docker Compose are container orchestration frameworks. Kubernetes runs containers across a network of physical or virtual computers. Docker Compose runs containers on a single host machine. In this blog post, we will compare Kubernetes and Docker-compose.
What exactly is Docker-compose?
Compose is a Docker application for defining and running multi-container Docker applications. Compose uses a YAML file to configure the services in your application. Then, you create and start all of the services specified in your configuration with a single command. Work in all environments, including production, staging, development, testing, and continuous integration workflows, to create work.
The orchestration is configured by Compose using the docker-compose.yml file. It specifies which images are required, which ports must be opened, whether they have access to the host filesystem, which commands must be executed upon startup, and other information. A docker-compose.yml file that incorporates a database into the stack while still using Dockerfile. The docker-compose.yml file looks like this:
version: ‘3’
services:
web:
build: .
ports:
– “8080:80”
db:
image: mysql
ports:
– “3306:3306”
environment:
– MYSQL_ROOT_PASSWORD=password
– MYSQL_USER=user
– MYSQL_PASSWORD=password
– MYSQL_DATABASE=demodb
The docker-compose.yml file will be written once and reused. Create a Dockerfile for a stack element with docker-compose.yml and reuse it for multiple stacks. Dockerfiles are simple text files containing the commands to assemble an image that will be used to deploy containers, whereas Docker-compose.yml files are used to define and run multi-container Docker applications.
As a result, the workflow will work as follows:
1) Create Dockerfiles to build images.
2) Using the Dockerfile images defined in docker-compose.yml, build complex stacks (consisting of individual containers).
3) Deploy the entire stack with the docker-compose command.
Common Docker Compose Use Cases
Docker Compose is a well-known tool for creating a microservice infrastructure environment that connects different services across a network. Docker Compose is used frequently in our test suites to create and destroy isolated testing environments. Furthermore, for scalability, we can look at Docker Swarm, a Docker project that works at the orchestration level, similar to Kubernetes.
In comparison, Docker Swarm has fewer features than Kubernetes.
What exactly is Kubernetes?
“Kubernetes” is a Greek word that means “helmsman” or “pilot,” which explains how the logo came to be. Let us now turn to the technical side of things. Due to the limitations of Docker, Kubernetes enters the picture to fill the gaps in the Docker containerization process. K8s is a containerization orchestration platform that allows you to run dynamically scaling containerized applications and manage them through an API.
The architecture of Kubernetes is straightforward: it consists of Master nodes and Worker nodes, with the Master communicating with the Worker via an API server. Multiple Master nodes may exist to provide High Availability, an important aspect of application deployment and a benefit of Kubernetes.
Kubernetes supports declarative and imperative approaches, allowing us to create, update, delete, or scale Objects using templates. As an example, consider the following deployment template:
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-deployment
labels:
app: nginx
spec:
replicas: 3
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
– name: nginx
image: nginx:1.14.2
ports:
– containerPort: 80
Differences between Kubernetes and Docker-compose
In a nutshell, Kubernetes and Docker are container orchestration frameworks. The primary distinction is that Kubernetes manages containers across multiple computers, virtual or physical, whereas Docker Compose manages containers on a single host machine.
Kubernetes has solved several significant application administration issues, including:
- resource optimization
- Self-healing containers
- Downtimes during application redeployment
- Auto-scaling
- Finally, Kubernetes orchestrates the deployment of multiple isolated containers so that resources are always available and can be distributed optimally.
On the other hand, Docker Compose can configure all of the application’s service dependencies to get started with, say, our automated tests. As a result, it is a potent tool for local development.
Which is better, Docker or Kubernetes?
Seriously, both! Docker can be used on your laptop to create container images, which can then be run on a Kubernetes cluster. Alternatively, instead of Kubernetes, you can use Docker Swarm to orchestrate your containers.
Should you start with Docker or Kubernetes?
If you intend to work with Kubernetes, you should first become acquainted with Docker. Docker will teach you the basics of containers, such as creating an image, running containers, and adding storage and environment variables.
Then connecting Kubernetes concepts like Pods and PersistentVolumes to your container knowledge will be much easier.
Docker allows you to do a variety of things, including:
- With a docker build and a Dockerfile, you can create container images (also known as Docker images) for your applications.
- Docker Engine can be used to run your own container images.
- Push images to a private image registry to share with coworkers or other teams.
- Push images to Docker Hub to share them on the internet (a public image registry)
- Use Docker Hub images to run third-party containers such as databases.
- Docker Compose allows you to run multi-container applications.
In addition to these useful developer features, Docker Swarm mode is a utility for managing a cluster of Docker instances. Swarm allows you to manage containers running on multiple servers.
What should you do with a Kubernetes cluster once it’s up and running? Why are people interested in Kubernetes?
- Create and deploy your own container-based applications.
- Deploy third-party container-based applications such as databases or web apps.
- Connect your apps to each other, for example, so that your back-end API can communicate with the database, or connect many containers into a microservices architecture.
- Stop existing containers and start new ones with the updated software to upgrade applications.
- Collect metrics on your apps, such as memory and CPU usage.
Learn more about Docker & Kubernetes
Conclusion
In this Blog, we looked at how Docker Compose and Kubernetes differ. Docker Compose can be useful when we need to define and run multi-container Docker applications. Suppose you want to learn how to build and run containers, and install Docker on your laptop. Then, use Kubernetes to orchestrate and run your containers in production! Kubernetes is a powerful but complex framework for managing clustered containerized applications.