111 lines
3.2 KiB
Markdown
111 lines
3.2 KiB
Markdown
# VPN
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Kilo enables peers outside of a Kubernetes cluster to connect to the created WireGuard network.
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This enables several use cases, for example:
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* giving cluster applications secure access to external services, e.g. services behind a corporate VPN;
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* improving the development flow of applications by running them locally and connecting them to the cluster;
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* allowing external services to access the cluster; and
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* enabling developers and support to securely debug cluster resources.
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In order to declare a peer, start by defining a Kilo Peer resource.
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See the following `peer.yaml`, where the `publicKey` field holds a [generated WireGuard public key](https://www.wireguard.com/quickstart/#key-generation):
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```yaml
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apiVersion: kilo.squat.ai/v1alpha1
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kind: Peer
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metadata:
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name: squat
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spec:
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allowedIPs:
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- 10.5.0.1/32 # Example IP address on the peer's interface.
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publicKey: GY5aT1N9dTR/nJnT1N2f4ClZWVj0jOAld0r8ysWLyjg=
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persistentKeepalive: 10
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```
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Then, apply the resource to the cluster:
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```shell
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kubectl apply -f peer.yaml
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```
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Now, the `kgctl` tool can be used to generate the WireGuard configuration for the newly defined peer:
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```shell
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PEER=squat
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kgctl showconf peer $PEER
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```
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This will produce some output like:
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```ini
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[Peer]
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PublicKey = 2/xU029dz/WtvMZAbnSzmhicl8U1/Y3NYmunRr8EJ0Q=
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AllowedIPs = 10.4.0.2/32, 10.2.3.0/24, 10.1.0.3/32
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Endpoint = 108.61.142.123:51820
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```
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The configuration can then be applied to a local WireGuard interface, e.g. `wg0`:
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```shell
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IFACE=wg0
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kgctl showconf peer $PEER > peer.ini
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sudo wg setconf $IFACE peer.ini
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```
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Finally, in order to access the cluster, the client will need appropriate routes for the new configuration.
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For example, on a Linux machine, the creation of these routes could be automated by running:
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```shell
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for ip in $(kgctl showconf peer $PEER | grep AllowedIPs | cut -f 3- -d ' ' | tr -d ','); do
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sudo ip route add $ip dev $IFACE
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done
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```
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Once the routes are in place, the connection to the cluster can be tested.
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For example, try connecting to the API server:
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```shell
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curl -k https://$(kubectl get endpoints kubernetes | tail -n +2 | tr , \\t | awk '{print $2}')
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```
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Likewise, the cluster now also has layer 3 access to the newly added peer.
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From any node or Pod on the cluster, one can now ping the peer:
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```shell
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ping 10.5.0.1
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```
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If the peer exposes a layer 4 service, for example an HTTP server listening on TCP port 80, then one could also make requests against that endpoint from the cluster:
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```shell
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curl http://10.5.0.1
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```
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Kubernetes Services can be created to provide better discoverability to cluster workloads for services exposed by peers, for example:
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```shell
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cat <<'EOF' | kubectl apply -f -
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apiVersion: v1
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kind: Service
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metadata:
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name: important-service
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spec:
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ports:
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- port: 80
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---
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apiVersion: v1
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kind: Endpoints
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metadata:
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name: important-service
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subsets:
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- addresses:
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- ip: 10.5.0.1
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ports:
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- port: 80
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EOF
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```
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[See the multi-cluster services docs for more details on connecting clusters to external services](./multi-cluster-services.md).
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Although it is not a primary goal of the project, the VPN created by Kilo can also be [used by peers as a gateway to the Internet; for more details, see the VPN server docs](./vpn-server.md).
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