The cluster may pull from dockerhub quite often and hit limits on pulls:
anonymous: 100 per 6 hours free: 200 per 6 hours paid: unlimited
Add your docker credentials to a cluster secret to improve your limits by running
./add-docker-secret.switch
Update each deployment that you want to use the creds with
spec:
...
template:
...
spec:
imagePullSecrets:
- name: regcred
You will need to redoply the secret into the same namespace as the deployment.