ERROR Unable to push image 'library/web:latest' to registry 'docker.io'. Error: denied: requested access to the resource is denied - Kompose up

Question

I have a simple docker-compose.yml file defined this way:

version: '3'
services:
  db:
    image: postgres:10.5-alpine
    ports:
      - 5432:5432
    volumes:
      - ./tmp/postgres_data:/var/lib/postgresql/data
  web:
    build:
      context: .
      dockerfile: Dockerfile
    command: /bin/bash -c "rm -f /tmp/server.pid && bundle exec rails server -b 0.0.0.0 -P /tmp/server.pid"
    ports:
      - 3000:3000
    depends_on:
      - db
    volumes:
      - .:/app 

I'm using [ Kompose ] ( https://kubernetes.io/docs/tasks/configure-pod-container/translate-compose-kubernetes/#kompose-up ) for converting my docker-compose.yml to Kubernetes

When I do kompose convert , everything looks fine.

This is the output:

 ✗ kompose convert  
    INFO Kubernetes file "db-service.yaml" created    
    INFO Kubernetes file "web-service.yaml" created   
    INFO Kubernetes file "db-deployment.yaml" created 
    INFO Kubernetes file "db-claim0-persistentvolumeclaim.yaml" created 
    INFO Kubernetes file "web-deployment.yaml" created 
    INFO Kubernetes file "web-claim0-persistentvolumeclaim.yaml" created 

My issue is when I do kompose up I get the following errors

✗ kompose up   
WARN Volume mount on the host "/Users/salo/Desktop/ibm-watson-ruby/tmp/postgres_data" isn't supported - ignoring path on the host 
INFO Build key detected. Attempting to build image 'web' 
INFO Building image 'web' from directory 'ibm-watson-ruby' 
INFO Image 'web' from directory 'ibm-watson-ruby' built successfully 
INFO Push image enabled. Attempting to push image 'web' 
INFO Pushing image 'library/web:latest' to registry 'docker.io' 
WARN Unable to retrieve .docker/config.json authentication details. Check that 'docker login' works successfully on the command line.: Failed to read authentication from dockercfg 
INFO Authentication credentials are not detected. Will try push without authentication. 
INFO Attempting authentication credentials 'docker.io 
ERRO Unable to push image 'library/web:latest' to registry 'docker.io'. Error: denied: requested access to the resource is denied 
FATA Error while deploying application: k.Transform failed: Unable to push Docker image for service web: unable to push docker image(s). Check that `docker login` works successfully on the command line 

As a note, I'm currently logged in to my Docker Hub account. I did docker login

Thanks in advance: :)

Answer 1

Kubernetes basically requires a Docker registry to be able to work; it cannot build local images. You mention you have a Docker Hub account, so you need to add a reference to that as the container's image: in the docker-compose.yml file.

version: '3'
services:
  web:
    build: .
    image: myname/web # <-- add this line
    ports:
      - 3000:3000
    depends_on:
      - db
    # command: is in the image
    # volumes: overwrite code in the image and don't work in k8s

When Kompose tries to push the image, it will use the image: name. You should be able to separately attempt to docker-compose push which will do the same thing.

Note that I deleted the volumes: that bind-mounts your application code into your container. This setup does not work in Kubernetes: it doesn't have access to your local system and you can't predict which node will actually be running your application. It's worth double-checking in plain Docker that your built image works the way you expect, without overwriting its code. (Debugging this in Docker will be easier than debugging it in Kubernetes.)