Setup edge cluster local image registry for K3s

Note: Skip this section if using remote image registry.

Procedure

Create the K3s image registry service:

a. Set USE_EDGE_CLUSTER_REGISTRY environment variable to true. This env indicates agent-install.sh script to use local image registry:

export USE_EDGE_CLUSTER_REGISTRY=true

b. Download the configuration file for the persistent volume claim from the server:

curl -sSLO https://raw.githubusercontent.com/open-horizon/open-horizon.github.io/master/docs/installing/k3s-persistent-claim.yaml

c. Create the persistent volume claim:

kubectl apply -f k3s-persistent-claim.yaml

d. Verify that the persistent volume claim was created and it is in “Pending” status:

kubectl get pvc

e. Create a file called k3s-registry-deployment.yaml with this content:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: docker-registry
  labels:
    app: docker-registry
spec:
  replicas: 1
  selector:
    matchLabels:
      app: docker-registry
  template:
    metadata:
      labels:
        app: docker-registry
    spec:
      volumes:
        - name: registry-pvc-storage
          persistentVolumeClaim:
            claimName: docker-registry-pvc
      containers:
        - name: docker-registry
          image: registry
          ports:
            - containerPort: 5000
          volumeMounts:
            - name: registry-pvc-storage
              mountPath: /var/lib/registry
---
apiVersion: v1
kind: Service
metadata:
  name: docker-registry-service
spec:
  selector:
    app: docker-registry
  type: NodePort
  ports:
    - protocol: TCP
      port: 5000

Or download it from the server:

curl -sSLO https://raw.githubusercontent.com/open-horizon/open-horizon.github.io/master/docs/installing/k3s-registry-deployment.yaml

f. Create the registry deployment and service:

kubectl apply -f k3s-registry-deployment.yaml

g. Verify that the service was created:

kubectl get deployment
kubectl get service

h. Define the registry endpoint:

export REGISTRY_ENDPOINT=$(kubectl get service docker-registry-service | grep docker-registry-service | awk '{print $3;}'):5000
cat << EOF >> /etc/rancher/k3s/registries.yaml
mirrors:
  "$REGISTRY_ENDPOINT":
    endpoint:
      - "http://$REGISTRY_ENDPOINT"
EOF

i. Restart K3s to pick up the change to /etc/rancher/k3s/registries.yaml:

systemctl restart k3s

Define this registry to Docker as an insecure registry:
a. Install Docker (if not already installed, docker --version to check):
```
curl -fsSL get.docker.com | sh
```
b. Create or add to /etc/docker/daemon.json (replacing <registry-endpoint> with the value of the $REGISTRY_ENDPOINT environment variable you obtained in a previous step):
```
{
  "insecure-registries": [ "<registry-endpoint>" ]
}
```
c. Restart Docker to pick up the change:
```
systemctl restart docker
```
d. Install jq:
```
apt-get -y install jq
```

What’s next

Installing the agent on K3s and MicroK8s edge clusters