How to migrate from Docker compose to Kubernetes?

– A guide. –

1. introduction to Docker Compose and Kubernetes

Docker Compose

Docker Compose is a tool that can be used to define and start container-based applications using a YAML file.
It is ideal for local development and testing, but only offers limited functions for large-scale production use.

Kubernetes

Kubernetes is an open source orchestration tool for container applications.
It offers extensive functions for the management, scaling and maintenance of container clusters, making it a preferred choice for productive use.

2. reasons for migration

The migration from Docker Compose to Kubernetes brings numerous advantages, including

• Scalability: Kubernetes enables the automatic scaling of applications based on demand.
• Reliability: Kubernetes ensures that applications continue to run even if individual components fail.
• Automation: Kubernetes offers extensive automation functions for deployment, rollbacks and updates.
• Flexibility: Kubernetes supports a wide range of infrastructure and platform integrations.

3. preparations for migration

Before you start the migration, you should make the following preparations:

• Analyze existing Docker Compose files: Understand the configuration and dependencies of your current containers.
• Create a plan: Define the steps and resources required for the migration.
• Set up your environment: Make sure you have access to a Kubernetes cluster, be it local (minikube) or in the cloud (e.g. Google Kubernetes Engine, AWS EKS).

4. step-by-step guide to migration

Creating the Kubernetes YAML files

In Docker Compose, you define your services in a docker-compose.yml file.
In Kubernetes, however, you need to create multiple YAML files for different objects such as deployments, services and ConfigMaps.

Example of a web service:

docker-compose.yml:

version: '3'
services:
web:
image: my-web-app
ports:
- "80:80"

Corresponding Kubernetes YAML files:deployment.yaml:

apiVersion: apps/v1
kind: Deployment
metadata:
name: web-deployment
spec:
replicas: 3
selector:
matchLabels:
app: web
template:
metadata:
labels:
app: web
spec:
containers:
- name: web
image: my-web-app
ports:
- containerPort: 80

service.yaml:

apiVersion: v1
kind: Service
metadata:
name: web-service
spec:
selector:
app: web
ports:
- protocol: TCP
port: 80
targetPort: 80
type: LoadBalancer


Configuration of Kubernetes objects

Make sure that you configure all necessary Kubernetes objects to replace the services defined in Docker Compose. These include:

• ConfigMaps and Secrets: For managing configuration data and sensitive information.
• Persistent volumes and persistent volume claims: For data persistence.

Network and storage configuration

Kubernetes offers extensive network and storage options.
Make sure you choose the right network configuration (e.g. Services, Ingress) and storage solutions (e.g. Persistent Volumes) that meet your requirements.

Review and tests

After creating and configuring the Kubernetes YAML files, you should deploy them to your Kubernetes cluster and test them thoroughly.
Check the logs and make sure that all services work as expected.

5. common challenges and solutions

Network problems

Network problems are a common problem during migration, especially if services cannot communicate as expected.
Make sure that all network rules and policies are configured correctly.

Resource management

Another problem can be the management of resources (CPU, RAM).
Use Kubernetes features such as resource quotas and limit ranges to optimize resource usage.

6. conclusion

Migrating from Docker Compose to Kubernetes requires careful planning and preparation, but can offer significant benefits in terms of scalability, resilience and automation.
With the steps and best practices described above, you can perform a successful migration and realize the full potential of Kubernetes.
If required, BITS GmbH is available with its expert knowledge to support you at every step of the migration process.
Contact us for comprehensive advice and support with your Docker compose to Kubernetes migration.