Kompose A tool to solve kubernetes docker deployments

Previous Blog regarding Docker and Kubernetes : Here

Have you ever faced the problem on deploying a custom docker image from your local docker to Kubernetes?

Actually, there are 2 ways that can solve this problem

1. Pushing your Docker Image to any Image repository

2. Somehow tell your kubernetes (In my case minikube) to use local docker images ( Because by default minikube does not search or use pre-pulled images for deploying)

the first way comes handy for most cases because it is easy.

But for development sometimes the scenario can occur that exposing the image to any public repository may be risky.

So in that case the first method becomes invalid .

The second method comes in place which is :

We have to somehow point a local docker build be automatically done in minikube space:

Step : 1
$ eval $(minikube docker-env)

window 1
$ minikube ssh
$ docker images

window 2
$ docker images

check the o/p of window 1 and window 2 are same or not if yes then the work is done:

Now any docker build will automatically create docker image under minikube spaceNow the Problem is

Now the problem with this method is though it is handy but, it is not kind of industry practice plus in real Kubernetes cluster, it may break the whole architecture.

What is the solution?

here comes the use of Kompose i.e Docker Compose + Kubernetes = Kompose.

What’s Kompose?

Kompose is a conversion tool for Docker Compose to container orchestrators such as Kubernetes (or OpenShift).

Why do developers love it?

• Simplify your development process with Docker Compose and then deploy your containers to a production cluster
• Convert your docker-compose.yaml with one simple command kompose convert
• Immediately bring up your cluster with kompose up
• Bring it back down with kompose down

Visit Their own website

Hands-on Kompose

Install Compose

Create a directory in your filesystem and name it kompose (for ease of identification)

$ cd kompose

For Linux :

Download Kompose:
$curl -L https://github.com/kubernetes/kompose/releases/download/v1.16.0/kompose-linux-amd64 -o kompose

After downloading

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

Now you are good to go.

Start minikube

$ minikube start
Starting local Kubernetes v1.10.0 cluster…
Starting VM…
Getting VM IP address…
Moving files into cluster…
Setting up certs…
Connecting to cluster…
Setting up kubeconfig…
Starting cluster components…
Kubectl is now configured to use the cluster.
Loading cached images from config file.

here I am working with a demo docker-compose.yaml

$ wget https://raw.githubusercontent.com/kubernetes/kompose/master/examples/docker-compose.yaml

Contents :

docker-compose.yaml

now converting this Kompose file we can get all required deployment and service yaml(s)from this.

$ kompose convert                           
INFO Kubernetes file "frontend-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 "redis-master-deployment.yaml" created  
INFO Kubernetes file "redis-slave-deployment.yaml" created

now do a ls to see all the yaml(s) are created or not.

$ ls -l
docker-compose.yaml
frontend-deployment.yaml
frontend-service.yaml
redis-master-deployment.yaml
redis-master-service.yaml
redis-slave-deployment.yaml
redis-slave-service.yaml

Now to create the deployments and services in kubernetes we can Kompose up

$ kompose up
We are going to create Kubernetes Deployments, Services and PersistentVolumeClaims 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          
INFO Successfully created Service: web            
INFO Successfully created Deployment: redis       
INFO Successfully created Deployment: web         

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

Now check whether your deployments are ready or not :

run :

$ kubectl get deployment,svc,pods,pvc

The output should contain the following images:

Deployments:

redis-master, redis-slave & frontend

Services :

redis-master, redis-slave & frontend

and redis-master and redis slave pods

check minikube dashboard

$ minikube dashboard

After the deployments and image pull is complete check for the url to view the output

$ minikube service frontend — url
http://192.168.99.100:31476

Visit the site and check whether it is working or not :

Output

Now we can easily view how this tool Kompose makes our life easy .

For The full Blog regarding Kubernetes and Docker please visit

docker and kubernetes The beginners introduction

Visit my medium profile for more such blogs:

Arani Mukherjee - Medium

Big Data Developer @ ThirdEyeData