kompose
is a tool to help users, familiar with docker-compose
, move to Kubernetes. It takes a Docker Compose file and translates it into Kubernetes resources.
kompose
is a convenience tool to go from local Docker development to managing your application with Kubernetes. We don't assume that the transformation from docker compose format to Kubernetes API objects will be perfect, but it helps tremendously to start Kubernetizing your application.
In this example we will create OpenShift artifacts for guestbook app from the docker-compose file using kompose
.
This step will create the service.json, deploymentconfig.json and imagestream.json files for OpenShift.
$ kompose --provider=openshift convert
INFO[0000] file "frontend-service.json" created
INFO[0000] file "redis-master-service.json" created
INFO[0000] file "redis-slave-service.json" created
INFO[0000] file "frontend-deploymentconfig.json" created
INFO[0000] file "frontend-imagestream.json" created
INFO[0000] file "redis-master-deploymentconfig.json" created
INFO[0000] file "redis-master-imagestream.json" created
INFO[0000] file "redis-slave-deploymentconfig.json" created
INFO[0000] file "redis-slave-imagestream.json" created
Once generated, you can inspect the files and edit these files if you want to make some adddional changes as per your requirement.
{
"kind": "DeploymentConfig",
"apiVersion": "v1",
"metadata": {
"name": "redis-master",
"creationTimestamp": null,
"labels": {
"service": "redis-master"
}
},
"spec": {
"strategy": {
"resources": {}
},
"triggers": [
{
"type": "ConfigChange"
},
{
"type": "ImageChange",
"imageChangeParams": {
"automatic": true,
"containerNames": [
"redis-master"
],
"from": {
"kind": "ImageStreamTag",
"name": "redis-master:e2e"
}
}
}
],
"replicas": 1,
"test": false,
"selector": {
"service": "redis-master"
},
"template": {
"metadata": {
"creationTimestamp": null,
"labels": {
"service": "redis-master"
}
},
"spec": {
"containers": [
{
"name": "redis-master",
"image": " ",
"ports": [
{
"containerPort": 6379,
"protocol": "TCP"
}
],
"resources": {}
}
],
"restartPolicy": "Always"
}
}
},
"status": {}
}
If you prefer YAML
files instead of JSON
, you can do that using the -y
option like so :
$ kompose --provider=openshift convert -y
INFO[0000] file "redis-slave-service.yaml" created
INFO[0000] file "frontend-service.yaml" created
INFO[0000] file "redis-master-service.yaml" created
INFO[0000] file "redis-slave-deploymentconfig.yaml" created
INFO[0000] file "redis-slave-imagestream.yaml" created
INFO[0000] file "frontend-deploymentconfig.yaml" created
INFO[0000] file "frontend-imagestream.yaml" created
INFO[0000] file "redis-master-deploymentconfig.yaml" created
INFO[0000] file "redis-master-imagestream.yaml" created
You can inspect the file and make some additional changes, if required.
apiVersion: v1
kind: DeploymentConfig
metadata:
creationTimestamp: null
labels:
service: redis-slave
name: redis-slave
spec:
replicas: 1
selector:
service: redis-slave
strategy:
resources: {}
template:
metadata:
creationTimestamp: null
labels:
service: redis-slave
spec:
containers:
- env:
- name: GET_HOSTS_FROM
value: dns
image: ' '
name: redis-slave
ports:
- containerPort: 6379
protocol: TCP
resources: {}
restartPolicy: Always
test: false
triggers:
- type: ConfigChange
- imageChangeParams:
automatic: true
containerNames:
- redis-slave
from:
kind: ImageStreamTag
name: redis-slave:v1
type: ImageChange
status: {}
$ oc create -f <path/to/artifacts>
Parse a configuration file and create one or more OpenShift objects based on the file contents.
deploymentconfig "frontend" created
imagestream "frontend" created
service "frontend" created
deploymentconfig "redis-master" created
imagestream "redis-master" created
service "redis-master" created
deploymentconfig "redis-slave" created
imagestream "redis-slave" created
service "redis-slave" created
$ oc get svc
NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
frontend 172.30.99.116 <none> 80/TCP 2m
redis-master 172.30.94.229 <none> 6379/TCP 2m
redis-slave 172.30.43.20 <none> 6379/TCP 2m
$ oc get dc
NAME REVISION REPLICAS TRIGGERED BY
frontend 1 1 config,image(frontend:v4)
redis-master 1 1 config,image(redis-master:e2e)
redis-slave 0 1 config,image(redis-slave:v1)
$ oc get pods
NAME READY STATUS RESTARTS AGE
frontend-1-ojsux 1/1 Running 0 4m
redis-master-1-1ep72 1/1 Running 0 4m
$ curl <frontend-ip>:80
<html ng-app="redis">
<head>
<title>Guestbook</title>
<link rel="stylesheet" href="//netdna.bootstrapcdn.com/bootstrap/3.1.1/css/bootstrap.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.12/angular.min.js"></script>
<script src="controllers.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/angular-ui-bootstrap/0.13.0/ui-bootstrap-tpls.js"></script>
</head>
<body ng-controller="RedisCtrl">
<div style="width: 50%; margin-left: 20px">
<h2>Guestbook</h2>
<form>
<fieldset>
<input ng-model="msg" placeholder="Messages" class="form-control" type="text" name="input"><br>
<button type="button" class="btn btn-primary" ng-click="controller.onRedis()">Submit</button>
</fieldset>
</form>
<div>
<div ng-repeat="msg in messages track by $index">
{{msg}}
</div>
</div>
</div>
</body>
</html>
That's it! Your application has been deployed on OpenShift in just 2 simple steps.
Note: We can create route, that will expose the frontend service. But this has to be done manually by running oc expose frontend
because kompose doesn't support that yet.
Asciinema for the above steps.
There is one more way to deploy your aplication directly on OpenShift if you do not want to inspect the artifacts created by kompose. Hence you can completely skip step 1 mentioned in the previous method mentioned above
$ kompose --provider openshift up
This will crate the OpenShift artifacts and deploy it at the same time.
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[0000] Successfully created service: frontend
INFO[0000] Successfully created service: redis-master
INFO[0000] Successfully created service: redis-slave
INFO[0000] Successfully created deployment: frontend
INFO[0000] Successfully created ImageStream: frontend
INFO[0000] Successfully created deployment: redis-master
INFO[0000] Successfully created ImageStream: redis-master
INFO[0000] Successfully created deployment: redis-slave
INFO[0000] Successfully created ImageStream: redis-slave
Your application has been deployed to OpenShift. You can run 'oc get dc,svc,is' for details.
$ oc get svc
NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
frontend 172.30.152.108 <none> 80/TCP 3m
redis-master 172.30.31.110 <none> 6379/TCP 3m
redis-slave 172.30.220.107 <none> 6379/TCP 3m
$ oc get dc
NAME REVISION REPLICAS TRIGGERED BY
frontend 1 1 config,image(frontend:v4)
redis-master 1 1 config,image(redis-master:e2e)
redis-slave 0 1 config,image(redis-slave:v1)
$ oc get is
NAME DOCKER REPO TAGS UPDATED
frontend 172.30.78.228:5000/guestbook/frontend v4 5 minutes ago
redis-master 172.30.78.228:5000/guestbook/redis-master e2e 5 minutes ago
redis-slave 172.30.78.228:5000/guestbook/redis-slave v1
$ oc get pods
NAME READY STATUS RESTARTS AGE
frontend-1-3dx8l 1/1 Running 0 3m
redis-master-1-skbbu 1/1 Running 0 3m
$ curl <frontend-ip>:80
<html ng-app="redis">
<head>
<title>Guestbook</title>
<link rel="stylesheet" href="//netdna.bootstrapcdn.com/bootstrap/3.1.1/css/bootstrap.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.12/angular.min.js"></script>
<script src="controllers.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/angular-ui-bootstrap/0.13.0/ui-bootstrap-tpls.js"></script>
</head>
<body ng-controller="RedisCtrl">
<div style="width: 50%; margin-left: 20px">
<h2>Guestbook</h2>
<form>
<fieldset>
<input ng-model="msg" placeholder="Messages" class="form-control" type="text" name="input"><br>
<button type="button" class="btn btn-primary" ng-click="controller.onRedis()">Submit</button>
</fieldset>
</form>
<div>
<div ng-repeat="msg in messages track by $index">
{{msg}}
</div>
</div>
</div>
</body>
</html>
Your application has been deployed on OpenShift using one single command.
Note: We can create route, that will expose the frontend service. But this has to be done manually by running oc expose frontend
because kompose doesn't support that yet.
kompose
can do more. Feel free to explore it here.
kompose --help
to find out more options.
Use kompose convert --help
to find more about the convert sub command.