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Translate a Docker Compose File to Kubernetes Resources

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.

More information about Kompose can be found on the official http://kompose.io site.

kompose is a convenience tool to go from local Docker development to managing your application with Kubernetes. Transformation of the Docker Compose format to Kubernetes resources manifest may not be exact, but it helps tremendously when first deploying an application on Kubernetes.

Use Case

If you have a Docker Compose docker-compose.yml or a Docker Distributed Application Bundle docker-compose-bundle.dab file, you can convert it into Kubernetes deployments and services like this:

$ kompose -f docker-compose.yml convert
WARN: Unsupported key networks - ignoring
file "redis-svc.yaml" created
file "web-svc.yaml" created
file "web-deployment.yaml" created
file "redis-deployment.yaml" created

Installation

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

GitHub release

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

The current release we use is 0.5.0.

# Linux 
curl -L https://github.com/kubernetes-incubator/kompose/releases/download/v0.5.0/kompose-linux-amd64 -o kompose

# macOS
curl -L https://github.com/kubernetes-incubator/kompose/releases/download/v0.5.0/kompose-darwin-amd64 -o kompose

# Windows
curl -L https://github.com/kubernetes-incubator/kompose/releases/download/v0.5.0/kompose-windows-amd64.exe -o kompose.exe

Make the binary executable and move it to your PATH (e.g. /usr/local/bin)

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

Kompose convert

Currently Kompose supports to transform either Docker Compose file (both of v1 and v2) and experimental Distributed Application Bundles into Kubernetes and OpenShift objects. There is a couple of sample files in the examples/ directory for testing. You will convert the compose or dab file to Kubernetes or OpenShift objects with kompose convert.

Kubernetes

$ cd examples/

$ ls
docker-compose.yml  docker-compose-bundle.dab  docker-gitlab.yml  docker-voting.yml

$ kompose -f docker-gitlab.yml convert
file "redisio-svc.yaml" created
file "gitlab-svc.yaml" created
file "postgresql-svc.yaml" created
file "gitlab-deployment.yaml" created
file "postgresql-deployment.yaml" created
file "redisio-deployment.yaml" created

$ ls *.yaml
gitlab-deployment.yaml  postgresql-deployment.yaml  redis-deployment.yaml    redisio-svc.yaml  web-deployment.yaml
gitlab-svc.yaml         postgresql-svc.yaml         redisio-deployment.yaml  redis-svc.yaml    web-svc.yaml

You can try with a Docker Compose version 2 like this:

$ kompose --file docker-voting.yml convert
WARN Unsupported key networks - ignoring
WARN Unsupported key build - ignoring
file "worker-svc.yaml" created
file "db-svc.yaml" created
file "redis-svc.yaml" created
file "result-svc.yaml" created
file "vote-svc.yaml" created
file "redis-deployment.yaml" created
file "result-deployment.yaml" created
file "vote-deployment.yaml" created
file "worker-deployment.yaml" created
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-compose-bundle.dab  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
file "frontend-service.yaml" created         
file "mlbparks-service.yaml" created         
file "mongodb-service.yaml" created          
file "redis-master-service.yaml" created     
file "redis-slave-service.yaml" created      
file "frontend-deployment.yaml" created      
file "mlbparks-deployment.yaml" created      
file "mongodb-deployment.yaml" created       
file "mongodb-claim0-persistentvolumeclaim.yaml" created 
file "redis-master-deployment.yaml" created  
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 over ridden by subsequent file.

Using --bundle, --dab to specify a DAB file as below:

$ kompose --bundle docker-compose-bundle.dab convert
WARN: Unsupported key networks - ignoring
file "redis-svc.yaml" created
file "web-svc.yaml" created
file "web-deployment.yaml" created
file "redis-deployment.yaml" created

OpenShift

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

In similar way you can convert DAB files to OpenShift. console $ kompose --bundle docker-compose-bundle.dab --provider openshift convert WARN: Unsupported key networks - ignoring INFO file "redis-svc.yaml" created INFO file "web-svc.yaml" created INFO file "web-deploymentconfig.yaml" created INFO file "web-imagestream.yaml" created INFO file "redis-deploymentconfig.yaml" created INFO file "redis-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 Buildconfig using git@github.com:rtnpro/kompose.git::master as source. 
INFO file "foo-deploymentconfig.yaml" created     
INFO file "foo-imagestream.yaml" created          
INFO file "foo-buildconfig.yaml" created

Note: If you are manually pushing the Openshift artifacts using oc create -f, you need to ensure that you push the imagestream artifact before the buildconfig artifact, to workaround this Openshift issue: https://github.com/openshift/origin/issues/4518 .

Kompose up

Kompose supports a straightforward way to deploy your “composed” application to Kubernetes or OpenShift via kompose up.

Kubernetes

$ kompose --file ./examples/docker-guestbook.yml up
We are going to create Kubernetes deployments and services for your Dockerized application.
If you need different kind of resources, use the 'kompose convert' and 'kubectl create -f' commands instead.

INFO Successfully created service: redis-master   
INFO Successfully created service: redis-slave    
INFO Successfully created service: frontend       
INFO Successfully created deployment: redis-master
INFO Successfully created deployment: redis-slave
INFO Successfully created deployment: frontend    

Your application has been deployed to Kubernetes. You can run 'kubectl get deployment,svc,pods' for details.

$ kubectl get deployment,svc,pods
NAME                               DESIRED       CURRENT       UP-TO-DATE   AVAILABLE   AGE
deploy/frontend                    1             1             1            1           4m
deploy/redis-master                1             1             1            1           4m
deploy/redis-slave                 1             1             1            1           4m

NAME                               CLUSTER-IP    EXTERNAL-IP   PORT(S)      AGE
svc/frontend                       10.0.174.12   <none>        80/TCP       4m
svc/kubernetes                     10.0.0.1      <none>        443/TCP      13d
svc/redis-master                   10.0.202.43   <none>        6379/TCP     4m
svc/redis-slave                    10.0.1.85     <none>        6379/TCP     4m

NAME                               READY         STATUS        RESTARTS     AGE
po/frontend-2768218532-cs5t5       1/1           Running       0            4m
po/redis-master-1432129712-63jn8   1/1           Running       0            4m
po/redis-slave-2504961300-nve7b    1/1           Running       0            4m

Note: - You must have a running Kubernetes cluster with a pre-configured kubectl context. - Only deployments and services are generated and deployed to Kubernetes. If you need different kind of resources, use the ‘kompose convert’ and ‘kubectl create -f’ commands instead.

OpenShift

$kompose --file ./examples/docker-guestbook.yml --provider openshift up
We are going to create OpenShift DeploymentConfigs and Services for your Dockerized application.
If you need different kind of resources, use the 'kompose convert' and 'oc create -f' commands instead.

INFO Successfully created service: redis-slave    
INFO Successfully created service: frontend       
INFO Successfully created service: redis-master   
INFO Successfully created deployment: redis-slave
INFO Successfully created ImageStream: redis-slave
INFO Successfully created deployment: frontend    
INFO Successfully created ImageStream: frontend   
INFO Successfully created deployment: redis-master
INFO Successfully created ImageStream: redis-master

Your application has been deployed to OpenShift. You can run 'oc get dc,svc,is' for details.

$ oc get dc,svc,is
NAME               REVISION                              DESIRED       CURRENT    TRIGGERED BY
dc/frontend        0                                     1             0          config,image(frontend:v4)
dc/redis-master    0                                     1             0          config,image(redis-master:e2e)
dc/redis-slave     0                                     1             0          config,image(redis-slave:v1)
NAME               CLUSTER-IP                            EXTERNAL-IP   PORT(S)    AGE
svc/frontend       172.30.46.64                          <none>        80/TCP     8s
svc/redis-master   172.30.144.56                         <none>        6379/TCP   8s
svc/redis-slave    172.30.75.245                         <none>        6379/TCP   8s
NAME               DOCKER REPO                           TAGS          UPDATED
is/frontend        172.30.12.200:5000/fff/frontend                     
is/redis-master    172.30.12.200:5000/fff/redis-master                 
is/redis-slave     172.30.12.200:5000/fff/redis-slave    v1

Note: - You must have a running OpenShift cluster with a pre-configured oc context (oc login)

Kompose down

Once you have deployed “composed” application to Kubernetes, kompose down will help you to take the application out by deleting its deployments and services. If you need to remove other resources, use the ‘kubectl’ command.

$ kompose --file docker-guestbook.yml down
INFO Successfully deleted service: redis-master   
INFO Successfully deleted deployment: redis-master
INFO Successfully deleted service: redis-slave    
INFO Successfully deleted deployment: redis-slave
INFO Successfully deleted service: frontend       
INFO Successfully deleted deployment: frontend

Note: - You must have a running Kubernetes cluster with a pre-configured kubectl context.

Alternate formats

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, Deamon Sets, or Helm charts.

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

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

$ kompose convert --rc 
file "redis-svc.yaml" created
file "web-svc.yaml" created
file "redis-rc.yaml" created
file "web-rc.yaml" created

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

$ kompose convert --ds 
file "redis-svc.yaml" created
file "web-svc.yaml" created
file "redis-daemonset.yaml" created
file "web-daemonset.yaml" created

The *-daemonset.yaml files contain the Daemon Set objects

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

$ kompose convert -c 
file "web-svc.yaml" created
file "redis-svc.yaml" created
file "web-deployment.yaml" created
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.

Unsupported docker-compose configuration options

Currently kompose does not support some Docker Compose options, which are listed on the conversion document.

For example:

$ cat nginx.yml
nginx:
  image: nginx
  dockerfile: foobar
  build: ./foobar
  cap_add:
    - ALL
  container_name: foobar

$ kompose -f nginx.yml convert
WARN Unsupported key build - ignoring             
WARN Unsupported key cap_add - ignoring           
WARN Unsupported key dockerfile - ignoring

Labels

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

For example:

version: "2"
services: 
  nginx:
    image: nginx
    dockerfile: foobar
    build: ./foobar
    cap_add:
      - ALL
    container_name: foobar
    labels: 
      kompose.service.type: nodeport

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 heppens 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

Note: controller object could be deployment or replicationcontroller, etc.

version: '2'

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

Warning about DeploymentConfig

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.

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