docker-kubernetes

Goal:

To run dotnet Rest Apis in a kubernetes cluster and establish asynchronous commnuication between them by using RabbitMq. This project has two services

1. PlatformService - uses Sql Server database
2. CommandService - uses InMemory data

Both the services will be running in a kubernetes cluster in their individual pods. Sql server will also be running in a separate pod. Outside Interaction with platformservice will be enabled with help of ingress nginx API gateway which will route requests to services based on path values.

Following are the steps to get these running in a kubernetes cluster

1. Build docker images from dockerfile for both the services. Make sure that docker desktop is running with kubernetes enabled on the development machine.
   • Go the /PlatformService folder and run the following command (Dont forget the period in the below command. It provides the build context) This will a create a image <docker-hub-id>/platformservice

     docker build -t <docker-hub-id>/platformservice .
     

   • Go the /CommandService folder and run the following command (Dont forget the period in the below command. It provides the build context) This will a create a image <docker-hub-id>/commandservice

     docker build -t <docker-hub-id>/commandservice .
     

2. Now that we have images, we will create running containers by running the below command

   docker run -d -p 8080:80 <docker-hub-id>/platformservice
   docker run -d -p 8080:80 <docker-hub-id>/commandservice
   

   Test each service by hitting below endpoints by using Postman

   (platformservice)  GET http://localhost:8080/api/platforms
   (commandservice) POST http://localhost:8080/api/c/platforms
   

   If successful response is received, we have running conatiners in docker.
3. Push these docker images to hub.docker.com by running below commands. These images will be used by kubernetes cluster later.

   docker push <docker-hub-id>/platformservice
   docker push <docker-hub-id>/commandservice
   

4. Now we will run these images inside a kubernetes cluster. Go the /K8S folder and run the following commands. This will create pods for platformservice and commandservice and will create CLusterIp services to enable interaction for outside world.

   kubectl apply -f platforms-depl.yaml
   kubectl apply -f commands-depl.yaml 
   

   To see the deployments

   kubectl get deployments    
   

   To get the pods

   kubectl get pods    
   

   To get the services (clusterIp services)

   kubectl get services   
   

5. Pods are ephemeral in nature, so direct access to pods is not allowed that is why we created clusterIp services to enable their interaction to outside world. One way for us to interact with pod is to make use of nodeport service. To start this service, go to K8S folder and run the below command

   kubectl apply -f platforms-np-srv.yaml
   

   To get the port from which we can access platformservice run the below command and look for servicetype ClusterIp and take note of the externalPort.

   kubectl get services
   

   Test platformservice by hitting below endpoints by using Postman

   GET http://localhost:<30xxx>/api/platforms
   

   Successful reponse indicates that we are now able to interact with the platformservice pod through a nodeport service.