How to Convert a docker-compose file to K8S manifest

#kubernetes #tutorial #docker #devops

How to Convert a Docker Compose File to Kubernetes Manifests Using Kompose

Many of us use Docker for local development, but when it’s time to run containers on Kubernetes, converting your setup can seem daunting. Kompose makes this transition easy by converting your docker-compose.yml into Kubernetes manifests.

Below are the latest steps to get your services running on Kubernetes:

1. Install Kompose (Latest Version)

On Mac (using Homebrew):

brew install kompose

Or download the latest release manually:

curl -L https://github.com/kubernetes/kompose/releases/latest/download/kompose-darwin-amd64 -o kompose
chmod +x kompose
sudo mv ./kompose /usr/local/bin/kompose

2. Prepare Your Docker Compose File

Build and push your Docker images to a remote registry.
Update your docker-compose.yml so that each service uses the image URL from your registry (not a local build context).

Example docker-compose.yml:

version: "3"
services:
  mythical-requester:
    image: <REMOTE-IMAGE>
    ports:
      - "4001:4001"
    environment:
      - NAMESPACE=production
      - LOGS_TARGET=http://loki:3100/loki/api/v1/push
      - TRACING_COLLECTOR_HOST=agent
      - TRACING_COLLECTOR_PORT=4317
      - OTEL_EXPORTER_OTLP_TRACES_INSECURE=true
      - OTEL_RESOURCE_ATTRIBUTES=ip=1.2.3.4

  mythical-server:
    image: <REMOTE-IMAGE>
    ports:
      - "4000:4000"
      - "80:80"
    depends_on:
      - mythical-database
    environment:
      - NAMESPACE=production
      - LOGS_TARGET=http://loki:3100/loki/api/v1/push
      - TRACING_COLLECTOR_HOST=agent
      - TRACING_COLLECTOR_PORT=4317
      - OTEL_EXPORTER_OTLP_TRACES_INSECURE=true
      - OTEL_RESOURCE_ATTRIBUTES=ip=1.2.3.5

  mythical-recorder:
    image: <REMOTE-IMAGE>
    ports:
      - "4002:4002"
    environment:
      - NAMESPACE=production
      - LOGS_TARGET=http://loki:3100/loki/api/v1/push
      - TRACING_COLLECTOR_HOST=agent
      - TRACING_COLLECTOR_PORT=4317
      - OTEL_EXPORTER_OTLP_TRACES_INSECURE=true
      - OTEL_RESOURCE_ATTRIBUTES=ip=1.2.3.5

3. Convert Docker Compose to Kubernetes Manifests

Run the following command in the directory containing your docker-compose.yml:

kompose convert

Kompose will generate Kubernetes YAML files for each service, typically creating both a deployment and a service manifest per service.

4. Deploy to Kubernetes

Move all generated YAML files to a folder (e.g., deployment/):
```
mkdir deployment
mv *.yaml deployment/
```
Connect to your Kubernetes cluster (ensure kubectl is configured).
Apply all manifests:
```
kubectl apply -f deployment/
```
Check your pods:
```
kubectl get pods
```