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Translate a Docker Compose File to Kubernetes Resources

What's Kompose? It's a conversion tool for all things compose (namely Docker Compose) to container orchestrators (Kubernetes or OpenShift).

More information can be found on the Kompose website at http://kompose.io.

Before you begin

You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. It is recommended to run this tutorial on a cluster with at least two nodes that are not acting as control plane hosts. If you do not already have a cluster, you can create one by using minikube or you can use one of these Kubernetes playgrounds:

To check the version, enter kubectl version.

Install Kompose

We have multiple ways to install Kompose. Our preferred method is downloading the binary from the latest GitHub release.

Kompose is released via GitHub on a three-week cycle, you can see all current releases on the GitHub release page.

# Linux
curl -L https://github.com/kubernetes/kompose/releases/download/v1.34.0/kompose-linux-amd64 -o kompose

# macOS
curl -L https://github.com/kubernetes/kompose/releases/download/v1.34.0/kompose-darwin-amd64 -o kompose

# Windows
curl -L https://github.com/kubernetes/kompose/releases/download/v1.34.0/kompose-windows-amd64.exe -o kompose.exe

chmod +x kompose
sudo mv ./kompose /usr/local/bin/kompose

Alternatively, you can download the tarball.

Installing using go get pulls from the master branch with the latest development changes.

go get -u github.com/kubernetes/kompose

Kompose is in EPEL CentOS repository. If you don't have EPEL repository already installed and enabled you can do it by running sudo yum install epel-release.

If you have EPEL enabled in your system, you can install Kompose like any other package.

sudo yum -y install kompose

Kompose is in Fedora 24, 25 and 26 repositories. You can install it like any other package.

sudo dnf -y install kompose

On macOS you can install the latest release via Homebrew:

brew install kompose

Use Kompose

In a few steps, we'll take you from Docker Compose to Kubernetes. All you need is an existing docker-compose.yml file.

  1. Go to the directory containing your docker-compose.yml file. If you don't have one, test using this one.

    
    services:
    
      redis-leader:
        container_name: redis-leader
        image: redis
        ports:
          - "6379"
    
      redis-replica:
        container_name: redis-replica
        image: redis
        ports:
          - "6379"
        command: redis-server --replicaof redis-leader 6379 --dir /tmp
    
      web:
        container_name: web
        image: quay.io/kompose/web
        ports:
          - "8080:8080"
        environment:
          - GET_HOSTS_FROM=dns
        labels:
          kompose.service.type: LoadBalancer
    
  2. To convert the docker-compose.yml file to files that you can use with kubectl, run kompose convert and then kubectl apply -f <output file>.

    kompose convert
    

    The output is similar to:

    INFO Kubernetes file "redis-leader-service.yaml" created
    INFO Kubernetes file "redis-replica-service.yaml" created
    INFO Kubernetes file "web-tcp-service.yaml" created
    INFO Kubernetes file "redis-leader-deployment.yaml" created
    INFO Kubernetes file "redis-replica-deployment.yaml" created
    INFO Kubernetes file "web-deployment.yaml" created
    
     kubectl apply -f web-tcp-service.yaml,redis-leader-service.yaml,redis-replica-service.yaml,web-deployment.yaml,redis-leader-deployment.yaml,redis-replica-deployment.yaml
    

    The output is similar to:

    deployment.apps/redis-leader created
    deployment.apps/redis-replica created
    deployment.apps/web created
    service/redis-leader created
    service/redis-replica created
    service/web-tcp created
    

    Your deployments are running in Kubernetes.

  3. Access your application.

    If you're already using minikube for your development process:

    minikube service web-tcp
    

    Otherwise, let's look up what IP your service is using!

    kubectl describe svc web-tcp
    
     Name:                     web-tcp
     Namespace:                default
     Labels:                   io.kompose.service=web-tcp
     Annotations:              kompose.cmd: kompose convert
                               kompose.service.type: LoadBalancer
                               kompose.version: 1.33.0 (3ce457399)
     Selector:                 io.kompose.service=web
     Type:                     LoadBalancer
     IP Family Policy:         SingleStack
     IP Families:              IPv4
     IP:                       10.102.30.3
     IPs:                      10.102.30.3
     Port:                     8080  8080/TCP
     TargetPort:               8080/TCP
     NodePort:                 8080  31624/TCP
     Endpoints:                10.244.0.5:8080
     Session Affinity:         None
     External Traffic Policy:  Cluster
     Events:                   <none>
    

    If you're using a cloud provider, your IP will be listed next to LoadBalancer Ingress.

    curl http://192.0.2.89
    
  4. Clean-up.

    After you are finished testing out the example application deployment, simply run the following command in your shell to delete the resources used.

    kubectl delete -f web-tcp-service.yaml,redis-leader-service.yaml,redis-replica-service.yaml,web-deployment.yaml,redis-leader-deployment.yaml,redis-replica-deployment.yaml
    

User Guide

Kompose has support for two providers: OpenShift and Kubernetes. You can choose a targeted provider using global option --provider. If no provider is specified, Kubernetes is set by default.

kompose convert

Kompose supports conversion of V1, V2, and V3 Docker Compose files into Kubernetes and OpenShift objects.

Kubernetes kompose convert example

kompose --file docker-voting.yml convert
WARN Unsupported key networks - ignoring
WARN Unsupported key build - ignoring
INFO Kubernetes file "worker-svc.yaml" created
INFO Kubernetes file "db-svc.yaml" created
INFO Kubernetes file "redis-svc.yaml" created
INFO Kubernetes file "result-svc.yaml" created
INFO Kubernetes file "vote-svc.yaml" created
INFO Kubernetes file "redis-deployment.yaml" created
INFO Kubernetes file "result-deployment.yaml" created
INFO Kubernetes file "vote-deployment.yaml" created
INFO Kubernetes file "worker-deployment.yaml" created
INFO Kubernetes file "db-deployment.yaml" created
ls
db-deployment.yaml  docker-compose.yml         docker-gitlab.yml  redis-deployment.yaml  result-deployment.yaml  vote-deployment.yaml  worker-deployment.yaml
db-svc.yaml         docker-voting.yml          redis-svc.yaml     result-svc.yaml        vote-svc.yaml           worker-svc.yaml

You can also provide multiple docker-compose files at the same time:

kompose -f docker-compose.yml -f docker-guestbook.yml convert
INFO Kubernetes file "frontend-service.yaml" created         
INFO Kubernetes file "mlbparks-service.yaml" created         
INFO Kubernetes file "mongodb-service.yaml" created          
INFO Kubernetes file "redis-master-service.yaml" created     
INFO Kubernetes file "redis-slave-service.yaml" created      
INFO Kubernetes file "frontend-deployment.yaml" created      
INFO Kubernetes file "mlbparks-deployment.yaml" created      
INFO Kubernetes file "mongodb-deployment.yaml" created       
INFO Kubernetes file "mongodb-claim0-persistentvolumeclaim.yaml" created
INFO Kubernetes file "redis-master-deployment.yaml" created  
INFO Kubernetes file "redis-slave-deployment.yaml" created   
ls
mlbparks-deployment.yaml  mongodb-service.yaml                       redis-slave-service.jsonmlbparks-service.yaml  
frontend-deployment.yaml  mongodb-claim0-persistentvolumeclaim.yaml  redis-master-service.yaml
frontend-service.yaml     mongodb-deployment.yaml                    redis-slave-deployment.yaml
redis-master-deployment.yaml

When multiple docker-compose files are provided the configuration is merged. Any configuration that is common will be overridden by subsequent file.

OpenShift kompose convert example

kompose --provider openshift --file docker-voting.yml convert
WARN [worker] Service cannot be created because of missing port.
INFO OpenShift file "vote-service.yaml" created             
INFO OpenShift file "db-service.yaml" created               
INFO OpenShift file "redis-service.yaml" created            
INFO OpenShift file "result-service.yaml" created           
INFO OpenShift file "vote-deploymentconfig.yaml" created    
INFO OpenShift file "vote-imagestream.yaml" created         
INFO OpenShift file "worker-deploymentconfig.yaml" created  
INFO OpenShift file "worker-imagestream.yaml" created       
INFO OpenShift file "db-deploymentconfig.yaml" created      
INFO OpenShift file "db-imagestream.yaml" created           
INFO OpenShift file "redis-deploymentconfig.yaml" created   
INFO OpenShift file "redis-imagestream.yaml" created        
INFO OpenShift file "result-deploymentconfig.yaml" created  
INFO OpenShift file "result-imagestream.yaml" created  

It also supports creating buildconfig for build directive in a service. By default, it uses the remote repo for the current git branch as the source repo, and the current branch as the source branch for the build. You can specify a different source repo and branch using --build-repo and --build-branch options respectively.

kompose --provider openshift --file buildconfig/docker-compose.yml convert
WARN [foo] Service cannot be created because of missing port.
INFO OpenShift Buildconfig using git@github.com:rtnpro/kompose.git::master as source.
INFO OpenShift file "foo-deploymentconfig.yaml" created     
INFO OpenShift file "foo-imagestream.yaml" created          
INFO OpenShift file "foo-buildconfig.yaml" created

Alternative Conversions

The default kompose transformation will generate Kubernetes Deployments and Services, in yaml format. You have alternative option to generate json with -j. Also, you can alternatively generate Replication Controllers objects, Daemon Sets, or Helm charts.

kompose convert -j
INFO Kubernetes file "redis-svc.json" created
INFO Kubernetes file "web-svc.json" created
INFO Kubernetes file "redis-deployment.json" created
INFO Kubernetes file "web-deployment.json" created

The *-deployment.json files contain the Deployment objects.

kompose convert --replication-controller
INFO Kubernetes file "redis-svc.yaml" created
INFO Kubernetes file "web-svc.yaml" created
INFO Kubernetes file "redis-replicationcontroller.yaml" created
INFO Kubernetes file "web-replicationcontroller.yaml" created

The *-replicationcontroller.yaml files contain the Replication Controller objects. If you want to specify replicas (default is 1), use --replicas flag: kompose convert --replication-controller --replicas 3.

kompose convert --daemon-set
INFO Kubernetes file "redis-svc.yaml" created
INFO Kubernetes file "web-svc.yaml" created
INFO Kubernetes file "redis-daemonset.yaml" created
INFO Kubernetes file "web-daemonset.yaml" created

The *-daemonset.yaml files contain the DaemonSet objects.

If you want to generate a Chart to be used with Helm run:

kompose convert -c
INFO Kubernetes file "web-svc.yaml" created
INFO Kubernetes file "redis-svc.yaml" created
INFO Kubernetes file "web-deployment.yaml" created
INFO Kubernetes file "redis-deployment.yaml" created
chart created in "./docker-compose/"
tree docker-compose/
docker-compose
├── Chart.yaml
├── README.md
└── templates
    ├── redis-deployment.yaml
    ├── redis-svc.yaml
    ├── web-deployment.yaml
    └── web-svc.yaml

The chart structure is aimed at providing a skeleton for building your Helm charts.

Labels

kompose supports Kompose-specific labels within the docker-compose.yml file in order to explicitly define a service's behavior upon conversion.

  • kompose.service.type defines the type of service to be created.

    For example:

    version: "2"
    services:
      nginx:
        image: nginx
        dockerfile: foobar
        build: ./foobar
        cap_add:
          - ALL
        container_name: foobar
        labels:
          kompose.service.type: nodeport
    
  • kompose.service.expose defines if the service needs to be made accessible from outside the cluster or not. If the value is set to "true", the provider sets the endpoint automatically, and for any other value, the value is set as the hostname. If multiple ports are defined in a service, the first one is chosen to be the exposed.

    • For the Kubernetes provider, an ingress resource is created and it is assumed that an ingress controller has already been configured.
    • For the OpenShift provider, a route is created.

    For example:

    version: "2"
    services:
      web:
        image: tuna/docker-counter23
        ports:
        - "5000:5000"
        links:
        - redis
        labels:
          kompose.service.expose: "counter.example.com"
      redis:
        image: redis:3.0
        ports:
        - "6379"
    

The currently supported options are:

Key Value
kompose.service.type nodeport / clusterip / loadbalancer
kompose.service.expose true / hostname

Restart

If you want to create normal pods without controllers you can use restart construct of docker-compose to define that. Follow table below to see what happens on the restart value.

docker-compose restart object created Pod restartPolicy
"" controller object Always
always controller object Always
on-failure Pod OnFailure
no Pod Never

For example, the pival service will become pod down here. This container calculated value of pi.

version: '2'

services:
  pival:
    image: perl
    command: ["perl",  "-Mbignum=bpi", "-wle", "print bpi(2000)"]
    restart: "on-failure"

Warning about Deployment Configurations

If the Docker Compose file has a volume specified for a service, the Deployment (Kubernetes) or DeploymentConfig (OpenShift) strategy is changed to "Recreate" instead of "RollingUpdate" (default). This is done to avoid multiple instances of a service from accessing a volume at the same time.

If the Docker Compose file has service name with _ in it (for example, web_service), then it will be replaced by - and the service name will be renamed accordingly (for example, web-service). Kompose does this because "Kubernetes" doesn't allow _ in object name.

Please note that changing service name might break some docker-compose files.

Docker Compose Versions

Kompose supports Docker Compose versions: 1, 2 and 3. We have limited support on versions 2.1 and 3.2 due to their experimental nature.

A full list on compatibility between all three versions is listed in our conversion document including a list of all incompatible Docker Compose keys.

Last modified June 21, 2024 at 10:11 AM PST: fix failing image pull and update commands and ouput (cca76d50c1)