I like to use Docker compose files for a couple of reasons. First, I have spent more time that I have in my vacation balance to understand the format. Second, they are great for local development even when I only have a single container, obfuscating the environment variables into a separate file and so on.
Since moving to more and more Kubernetes development, and getting in tune with the file spec for deployments; converting the compose files by hand have been painful at times especially with the complicated ones where there are a ton of containers, networking and environment variables.
Kompose to the rescue!
Through a quick search and reading the docs at kubernetes.io, I came across kompose.
kompose is a tool to help users who are familiar with docker-compose move to Kubernetes. kompose takes a Docker Compose file and translates it into Kubernetes resources.
Take the following docker-compose file as an example which defines a web application container and redis container:
version: '3'
services:
web:
build: .
ports:
- "5000:5000"
redis:
image: "redis:alpine"
Using the kompose convert, the following files are created.
INFO Kubernetes file "redis-service.yaml" created
INFO Kubernetes file "web-service.yaml" created
INFO Kubernetes file "redis-deployment.yaml" created
INFO Kubernetes file "web-deployment.yaml" created
A deployment and service file is created for each container defined in the docker-compose.yml file.
Use the --out|-o option to output a single file, for example:
kompose convert -f docker-compose-simple.yml -o simple.yml
The output for the kubernetes format result in:
Kompose is a great tool, I use Docker compose for local development and spinning up the environments, and when I am ready to push to the K8s cluster the deployment files can be converted and then kubectl create -f simple.yml to publish.
