A straight forward way to do this independent from minikube would be to use a imagePullSecrets configuration. As documented in the Pulling an Image from a Private Registry guide, you can create a Secret and use that along with your image like this:

apiVersion: v1
kind: Pod
metadata:
  name: demo-pod
spec:
  containers:
    - name: private-container
      image: <your-private-image>
  imagePullSecrets:
    - name: the_secret

Where the the_secret could be created with:

kubectl create secret docker-registry the_secret --docker-server=xxx --docker-username=xxx --docker-password=xxx --docker-email=xxx

Or with:

kubectl create secret generic the_secret --from-file=.docker/config.json

Or with anything else which is related to kubectl create secret - see documentation for details.

Edit: Even in the official minikube documentation you'll find that they use Secrets along with the registry-creds addon.

You'll find the generic documentation here and the documentation for the addon here.

It burns down to:

minikube addons enable registry-creds

But technically it does the same as described above.

To address:

x509: certificate signed by unknown authority

Could you please try the following suggestion from Minikube repo?

copy the cert into the VM. The location should be:

/etc/docker/certs.d/

from here: https://docs.docker.com/engine/security/certificates/

ref

That thread also includes the following one-liner:

cat <certificatefile> \
  | minikube ssh "sudo mkdir -p /etc/docker/certs.d/<domain> && sudo tee /etc/docker/certs.d/<domain>/ca.crt"

The issue here is the CA Trust chain of the Linux host that needs to be updated. The easiest way is to reboot the Linux host after copying the certs into the VM, if rebooting is not an option - look for a way to update-ca-certificates.

Just restarting the Docker Daemon will most likely not solve this issue

Note: allowing the Docker daemon to use insecure registries means certificates aren't verified.. while this may help, it does not solve the question asked here