In order to pull private dockerhub hosted images using kubernetes yaml use:
DOCKER_REGISTRY_SERVER=docker.io
DOCKER_USER=Type your dockerhub username, same as when you `docker login`
DOCKER_EMAIL=Type your dockerhub email, same as when you `docker login`
DOCKER_PASSWORD=Type your dockerhub pw, same as when you `docker login`
kubectl create secret docker-registry myregistrykey \
  --docker-server=$DOCKER_REGISTRY_SERVER \
  --docker-username=$DOCKER_USER \
  --docker-password=$DOCKER_PASSWORD \
  --docker-email=$DOCKER_EMAIL
This is what your yaml file should look like:
apiVersion: v1
kind: Pod
metadata:
  name: whatever
spec:
  containers:
    - name: whatever
      image: DOCKER_USER/PRIVATE_REPO_NAME:latest
      imagePullPolicy: Always
      command: [ "echo", "SUCCESS" ]
  imagePullSecrets:
    - name: myregistrykey
Then execute:
kubectl create -f example.yaml