# VPN Kilo enables peers outside of a Kubernetes cluster to connect to the created WireGuard network. This enables several use cases, for example: * giving cluster applications secure access to external services, e.g. services behind a corporate VPN; * allowing external services to access the cluster; and * enabling developers and support to securely debug cluster resources. In order to declare a peer, start by defining a Kilo Peer resource. See the following `peer.yaml`, where the `publicKey` field holds a [generated WireGuard public key](https://www.wireguard.com/quickstart/#key-generation): ```yaml apiVersion: kilo.squat.ai/v1alpha1 kind: Peer metadata: name: squat spec: allowedIPs: - 10.5.0.1/32 # Example IP address on the peer's interface. publicKey: GY5aT1N9dTR/nJnT1N2f4ClZWVj0jOAld0r8ysWLyjg= persistentKeepalive: 10 ``` Then, apply the resource to the cluster: ```shell kubectl apply -f peer.yaml ``` Now, the `kgctl` tool can be used to generate the WireGuard configuration for the newly defined peer: ```shell PEER=squat kgctl showconf peer $PEER ``` This will produce some output like: ```ini [Peer] PublicKey = 2/xU029dz/WtvMZAbnSzmhicl8U1/Y3NYmunRr8EJ0Q= AllowedIPs = 10.4.0.2/32, 10.2.3.0/24, 10.1.0.3/32 Endpoint = 108.61.142.123:51820 ``` The configuration can then be applied to a local WireGuard interface, e.g. `wg0`: ```shell IFACE=wg0 kgctl showconf peer $PEER > peer.ini sudo wg setconf $IFACE peer.ini ``` Finally, in order to access the cluster, the client will need appropriate routes for the new configuration. For example, on a Linux machine, the creation of these routes could be automated by running: ```shell for ip in $(kgctl showconf peer $PEER | grep AllowedIPs | cut -f 3- -d ' ' | tr -d ','); do sudo ip route add $ip dev $IFACE done ``` Once the routes are in place, the connection to the cluster can be tested. For example, try connecting to the API server: ```shell curl -k https://10.0.27.179:6443 ``` Likewise, the cluster now also has layer 3 access to the newly added peer. From any node or Pod on the cluster, one can now ping the peer: ```shell ping 10.5.0.1 ``` If the peer exposes a layer 4 service, for example an HTTP service, then one could also make requests against that endpoint from the cluster: ```shell curl http://10.5.0.1 ``` Kubernetes Services can be created to provide better discoverability to cluster workloads for services exposed by peers, for example: ```shell cat <<'EOF' | kubectl apply -f - apiVersion: v1 kind: Service metadata: name: important-service spec: ports: - port: 80 --- apiVersion: v1 kind: Endpoints metadata: name: important-service subsets: - addresses: - ip: 10.5.0.1 ports: - port: 80 EOF ``` [See the multi-cluster services docs for more details on connecting clusters to external services](./docs/multi-cluster-services.md).