Containers in a Kubernetes cluster don't seem to communicate

General Discussions
1

Cluster information:

Kubernetes version:1.25
Cloud being used:
Installation method:
Host OS: Linux
CNI and version:
CRI and version:

Hi guys, i’m new to the world of containerized apps with Docker and Kubernetes. Substantially i have to make a migration from Docker to Kubernetes of an already written application. I converted the docker-compose.yaml file with :
$ kompose convert -f docker-compose.yaml
and i got my deployments, persistenVolume and service yaml files. I also have to use a localhost registry, and i successfully created once as the official docker documentation suggest at https://docs.docker.com/registry/deploying/:

docker run -d -p 5000:5000 --restart=always --name registry registry:2

I tagged and pushed my images correctly to localhost:5000 and my pods are running correctly.
However i can’t make them communicate correctly, i guess it’s a problem with ports from the Docker environment to the Kubernetes one, and i think it’s mainly for the clusterIP service that Kubernetes uses. In specific words, i have a pod that runs a container with a Postgres db on it, and another one that runs the backend logic and needs to access the db.
Here are the ports specified in the db-service.yaml :

spec:
ports:
- name: “8543”
port: 8543
targetPort: 5432
selector:
io.kompose.service: db

the container port in the db-deployment.yaml :

ports:
- containerPort: 5432

the ports in the api-service.yaml (relative to backend) :

ports:
- name: “8000”
port: 8000
targetPort: 8000
selector:
io.kompose.service: api

and the port in the api-deployment.yaml (relative to backend):
ports:
- containerPort: 8000

2

You didn’t say anything about networking or how your cluster was created, so it’s a wild guess.

Try this: Debug Services | Kubernetes

3

Ye sorry i am using docker desktop on windows and i manage the cluster from the WSL with the kubectl apply. Hope i understood what i was missing

4

I have no hands-on experience with Docker desktop or Windows, really, so I can’t help too much. That doc details steps to figure out why services might not work, but it presupposes that the pod-to-pod network is correct, which is what I don’t know in your context.

5

The services are all clusterIP and i think it’s the main problem to handle in port configuration. Maybe this additional info can say you somethinq? Anyway, thanks for the attention!

6

Run thru that doc. Nothing seems obviously wrong in your config (as long as your apps are actually listening on 5432 and 8000, respectively).