tl;dr k3s private docker registry

gistfile1.txt

sudo apt install apache2-utils
htpasswd -Bc registry.password registry

kubectl create namespace cert-manager
kubectl apply -f https://github.com/jetstack/cert-manager/releases/download/v1.1.1/cert-manager.yaml

kubectl apply -f kube-docker-registry.yaml


kubectl create secret docker-registry regcred \
    --docker-server=r.example.org \
    --docker-username=<Profile name> \
    --docker-password=<password>


Add to enable pulling 

imagePullSecrets:
 - regcred

kube-docker-registry.yaml

apiVersion: cert-manager.io/v1
kind: ClusterIssuer
metadata:
  name: letsencrypt-prod
spec:
  acme:
    email: email@email.com
    privateKeySecretRef:
      name: prod-issuer-account-key
    server: https://acme-v02.api.letsencrypt.org/directory
    solvers:
      - http01:
          ingress:
            class: traefik
        selector: {}
---
apiVersion: v1
kind: Service
metadata:
  name: registry-service
spec:
  selector:
    app: registry
  ports:
    - protocol: TCP
      port: 5000
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: ingress
  annotations:
    kubernetes.io/ingress.class: traefik
    cert-manager.io/cluster-issuer: letsencrypt-prod
spec:
  tls:
  - hosts:
    - r.example.org
    secretName: r-example-org-tls  
  rules:
  - host: r.example.org
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: registry-service
            port:
              number: 5000
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: registry-persistent-volume-claim
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 5Gi
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: registry
  labels:
    app: registry
    group: registry
spec:
  replicas: 1
  selector:
    matchLabels:
      app: registry   
  template:
    metadata:
      labels:
        app: registry
        group: registry
    spec:
      volumes:
        - name: registry
          persistentVolumeClaim: 
            claimName: registry-persistent-volume-claim
        - name: htpasswd
          secret:
            secretName: registry-htpasswd                            
      containers:
        - name: registry
          image: registry:2
          ports: 
            - containerPort: 5000
          volumeMounts:
            - name: registry
              mountPath: /var/lib/registry
            - name: htpasswd
              mountPath: /auth
              readOnly: true
          env:
            - name: REGISTRY_AUTH
              value: htpasswd
            - name: REGISTRY_AUTH_HTPASSWD_REALM
              value: "Registry Realm"
            - name: REGISTRY_AUTH_HTPASSWD_PATH
              value: /auth/htpasswd
            - name: REGISTRY_STORAGE_DELETE_ENABLED
              value: "true"