Docker compose is a great tool for easily deploying docker container without having to write lengthy docker run commands. But what if I want to deploy my docker-compose.yaml file into Kubernetes?

Kompose is a tool that can convert docker compose files so that they can be deployed to a Kubernetes cluster.

Here’s a typical docker-compose.yaml file I use: –

version: '3'
 
services:
    sqlserver1:
        image: mcr.microsoft.com/mssql/server:2019-CTP3.1-ubuntu
        ports:  
          - "15789:1433"
        environment:
          SA_PASSWORD: "Testing1122"
          ACCEPT_EULA: "Y"
          MSSQL_DATA_DIR: "/var/opt/sqlserver/data"
          MSSQL_LOG_DIR: "/var/opt/sqlserver/log"
          MSSQL_BACKUP_DIR: "/var/opt/sqlserver/backup"
        volumes: 
          - sqlsystem:/var/opt/mssql/
          - sqldata:/var/opt/sqlserver/data
          - sqllog:/var/opt/sqlserver/log
volumes:
  sqlsystem:
  sqldata:
  sqllog:

This will spin up one container running SQL Server 2019 CTP 3.1, accept the EULA, set the SA password, and set the default location for the database data/log/backup files using named volumes created on the fly.

Let’s convert this using Kompose and deploy to a Kubernetes cluster.

To get started with Kompose first install by following the instructions here. I installed on my Windows 10 laptop so I downloaded the binary and added to my PATH environment variable.

Before running Kompose I had to make a slight change to the docker-compose.yaml file because when I deploy SQL Server to Kubernetes I want to create a LoadBalanced service so that I can connect to the SQL instance remotely. To get Kompose to create a LoadBalanced service I had to add the following to my docker-compose.yaml file (under the first volumes section): –

        labels:
          kompose.service.type: LoadBalancer

Then I navigated to the location of my docker-compose.yaml file and ran: –

kompose convert -f docker-compose.yaml

Which created the corresponding yaml files!

Looking through the created files, they all look good! The PVCs will use the default storage class of the Kubernetes cluster that you’re deploying to and the deployment/service don’t need any adjustment either.

So now that I have the yaml files to deploy into Kubernetes, I simply run:-

kompose up

And the files will be deployed to my Kubernetes cluster!

OK, kubectl describe pods will show errors initially when the pod is first created as the PVCs haven’t been created but it will retry.

Once the pod is up and the service has an external IP address, the SQL instance can be connected to. Nice and easy!

Cleaning up is also a cinch, just run:-

kompose down

And the objects will be deleted from the cluster.

Thanks for reading!